Although a bit of a sensationalist, Keith is not completely out of line and he isn’t the only Internet auto expert touting the effects of the industry required ZDDP (zinc dialkyl dithiophosphate) decrease in motor oil.

Twelve years ago, the maximum ZDDP level in passenger car motor oil was 1600ppm. Over the years, the EPA has slowly decreased the allowed amount to today’s range of 600-800ppm. ZDDP’s primary purpose is to prevent wear in high friction areas of the engine such as camshafts, connecting rods and lifters, which is probably why Keith is so concerned about its decline.

Less ZDDP = More engine wear?

The reduction of ZDDP in motor oils has caused many issues in flat tappet engines and a big stir in the classic car forum. Most V-8 engines in the muscle car era (cars built before 1975) came standard with a flat tappet camshaft and no catalytic converter. The flat tappet is, for the most part, flat on the bottom. Flat tappet cams are under a lot of pressure and require an extra oil additive for tight tolerances. Oil is the only thing between the lifter and camshaft lobe preventing them from welding each other together. Without sufficient lubrication during break-in and over long-term use, cams can suffer pitting, uneven lobes and severe wear patterns. So, in high performance or classic cars, opt for heavy-duty, performance or racing oils with higher levels of ZDDP that will provide flat tappet cams with anti-scuffing, anti-wear and oxidation inhibition.

Ok, so what about your basic passenger car? In the last decade or so, car manufacturers switched to more reliable, efficient roller camshafts for mass production. Because roller cams don’t require the same level of zinc protection as flat tappet cams, passenger car engines can afford a decrease in ZDDP. In fact, less ZDDP could actually be a good thing. Phosphorous—one of the main ingredients—is a poison to catalytic converters (fitted in most passenger cars since the mid-70s). Excessive ZDDP content will bond to the metal catalyst beads inside the converter rendering it useless as a pollution control device. See why the EPA wants to regulate the life requirement of the catalyst?

In order to meet API SM specifications, oil manufacturers must decrease ZDDP. Today’s modern passenger car oils contain other dedicated antioxidants to make up for the loss of ZDDP and resulting in a better overall product for consumers.

To sum up, less ZDDP is suitable for vehicles with roller cams and catalytic converters and bad for vehicles with flat tappet cams and no cat.

How can BG help?

BG MOA® uses a combination of additives that improve oil’s ability to withstand breakdown due to combustion byproducts, increased temperatures and loads, and frictional wear. And unlike many other oil additives, BG MOA® does not fully rely on ZDDP as its sole anti-wear additive and antioxidant. BG MOA® relies on its proprietary additives for extra wear protection and oxidation stability under severe condition—like that of engines with flat tappet cams. For cars with catalytic converters, BG MOA® only contains ZDDP to a similar concentration as a typical base engine oil, which is not enough to ruffle a cat’s fur.

If the cat already stinks, it doesn’t necessarily mean it’s poisoned by ZDDP. Chances are hydrocarbon deposits from combustion have plugged it up. And a dirty cat can pump noxious gases into the air and reduce engine performance. For extra protection of the catalytic converter and oxygen sensor, pour in a can of BG 44K® in the fuel tank every 7,500 miles. BG 44K® is proven to restore converter efficiency and remove deposits from the oxygen sensor ultimately restoring power and performance.

So the next time you hear someone like Keith yelling, “Oil is killing our cars!” recommend BG MOA® for superior lubrication and wear protection of the engine’s moving parts—even flat tappet cams.

This article has been reprinted from the Spring 2010 issue of the BG Blend’r newsletter, visit BGprod.com to learn more about BG Products, Inc.

Photo 1

When we’re attempting to diagnose a charging system failure, it helps to think of the battery’s state of charge (SOC) as a type of checking account. If we overdraw our account by writing one huge check (i.e. leaving the headlamps on overnight), we wake up the next morning with an engine that won’t crank. Or, if we overdraw our account by writing many small checks (i.e. short-trip driving, key-on, engine off accessory use) and not balancing our account at the end of the day, we again are greeted with a slow-cranking engine and an overdrawn charging system account.

A battery with a “balanced” checking account will maintain 12.6 volts across its terminals with the surface charge removed (See Photo 1). Surface charge is any terminal voltage higher than 12.6 volts. Turning on the headlamps for a few minutes is the quickest way to remove surface charge. If the voltage dips below 12.6 volts with the surface charge removed, a fully charged battery in good condition will quickly recuperate and return to 12.6 volts. For the sake of simplicity, I’m going to illustrate basic alternator testing tips throughout the following text using a 1997 Nissan Maxima with a conventional integral alternator/voltage regulator assembly.

Photo 2

Failure Patterns

The most common alternator failure is the glaring red “bat” light indicating a catastrophic alternator failure. Catastrophic failures are usually due to an alternator malfunction, but can also be caused by a faulty drive belt or blown fuse. A related alternator failure is the battery warning light illuminating on a random or intermittent basis because the alternator’s carbon brushes are sticking in their holders or are worn out.

Another common failure is the alternator bearings becoming dry or pitted, which causes a rough, growling sound to emanate from the alternator case. ­Although the noise might be intermittent at first, it will worsen with mileage. In most cases, bearing noise can be detected by using a common shop stethoscope to pinpoint the source of the sound.

A relatively rare failure is when one or more of the alternator’s three pairs of positive and negative voltage diodes develop a short or open-circuit failure. Because the diode’s job is to rectify alternating current (AC) into direct current (DC) that can be stored in a lead-acid battery, AC voltage begins to “leak” into the vehicle’s electrical system when a diode fails. See Photo 2.

Photo 3

This AC leakage causes an electrical “ripple” effect that can cause unpredictable problems with the operation of the vehicle’s on-board electronic systems. In this case also, the alternator generally loses about one-third of its charging capacity. Alternating current generally can be detected at the battery by connecting a multimeter set to the AC voltage position.

Battery Testing

Charging systems diagnostics is not for the untrained technician. Always remember that a charging battery produces explosive hydrogen gas. Shorting the battery terminals together with a wrench or other metallic object, or exposing a battery to a source of ignitions such as a flame or spark, can produce a catastrophic explosion.

Because the alternator’s charging rate is governed by the battery’s state-of-charge (SOC), it’s important that the battery condition is tested before the alternator is replaced (See Photo 3). In general, most conventional alternator systems produce about 14.2 volts at the terminals on a fully-charged battery at 70° F ambient temperature. Keep in mind that charging voltage increases at colder temperatures and decreases at warmer temperatures.

Photo 4

Because normal charging voltage can’t be achieved on a battery with a bad cell, the alternator will over-charge the remaining cells and boil the electrolyte. At the other extreme, a battery that is sulfated due to being under-charged or not seeing constant use will maintain normal charging voltages. The symptoms of a sulfated battery are that it charges very quickly and produces a very low amperage discharge rate. See Photo 4.

Two diagnostic methods are currently used to measure battery condition. Modern conductance testers measure electrical resistance in the battery by applying a mild alternating current to the battery ­terminals. See Photo 5.

Photo 5

A more conventional method of determining ­battery condition is to use an adjustable carbon pile load tester to discharge the battery at one-half of its rated cold-cranking amperage capacity (CCA). The battery should maintain at least 9.6 volts at its terminals after being discharged for no more than 15 seconds. See Photo 6.

Because new batteries typically test as much as 25% higher than their rated capacities, a new battery with a bad cell can occasionally pass both a conductance and a load test. A specific gravity tester can be used to detect a bad cell if the battery has removable cell caps. If in doubt, always substitute a known-good battery for accurate alternator testing.

Charging System Configurations

Photo 6

Early configurations generally located the voltage regulator on the firewall or fender well. Because corrosion usually increases the electrical resistance of the ground circuit through the body panels, the voltage regulator senses less than actual B+ voltage, which causes an overcharge at the battery.

To eliminate this possibility, many veteran technicians install an auxiliary ground wire from the regulator base to an alternator or engine ground. Alternator condition can generally be tested in these systems by disconnecting the voltage regulator and “full-fielding” the alternator. ­Always consult an ­applicable service manual before attempting a full-field test.

The most common charging system configuration is like the one on our 1997 Maxima, which integrates the voltage regulator with the alternator. Alternators with integral voltage regulators can often be full-fielded by inserting a metal pin through the ­alternator case to ground the B-brush on the alternator. Because it’s generally not cost-effective to replace integral voltage regulators, most shops replace the ­alternator as an assembly.

Photo 7

The latest configuration of charging systems use the vehicle’s Powertrain Control Module (PCM) to control the alternator’s charging rate. To achieve maximum fuel economy and minimum exhaust emissions, the PCMs in some configurations may charge the battery only during specific operating conditions. Remember that, because these systems are constantly measuring the battery’s state-of-charge (SOC), the battery should always be in good condition and fully charged. See Photo 7.

The best practice in diagnosing alternators on late-model imports is to connect a professional scan tool to measure charging voltage and to retrieve any possible charging system trouble codes. In many cases, the scan tool can be used to activate or control the field current to help evaluate the alternator’s output. When diagnosing these systems, always follow the auto manufacturer’s recommended test procedures.

Photo 8

Always keep in mind when diagnosing alternators that, to prevent damaging on-board electronics, the maximum allowable charging voltage in most systems is 17 volts. For that reason, I personally prefer not to “full-field” an alternator, even when that ­option is available.

Instead, I use a DVOM to measure available voltage at the alternator. If, for example, battery voltage isn’t available at the B+ terminal of the alternator, check the condition of the fusible link connecting the alternator to the battery. If the fusible link stretches when pulled or has no continuity, it should be replaced. Similarly, always use a DVOM to test the continuity of the alternator’s field fuse or to check for the presence of key-on field current at the alternator field connector. See Photo 8.

Load-Testing Alternators

Photo 9

Unless otherwise specified, the best method for testing conventional charging systems is to use an ­adjustable carbon pile tester to measure battery discharge rate and alternator charging rate.

Although load-testing an alternator provides a quick way to test for drive belt slippage, keep in mind that an alternator can easily be overheated when testing for maximum output during low-speed operation (See Photo 9).

Photo 10

The rated output for our ’97 Maxima equipped with the LR 1100-709 alternator is 35 amps at 1,300 rpm, 85 amps at 2,500 rpm and 105 amps at 5,000 rpm. Because carbon piles are designed only for 15 seconds of operation without overheating, keep the duration of load-testing as short as possible.

Summary

The most important issue in modern alternator testing is to identify and fully understand the operation of the charging system in question. Never jump to conclusions and never skip steps in the diagnostic process (See Photo 10). And, always remember that the heart of our charging system “checking account” is the battery itself.

Gary Goms is an author for autocarepro news. You can email Gary at goms@chaffee.net.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

Despite the slew of automotive recalls over the past year, a new survey conducted by Atlanta-based Speedemissions, Inc. indicates that 79% of the more than 1,300 people surveyed feel as safe or safer in their vehicles than they did a year ago.

However, a new iPhone application that analyzes an automobile’s computer system emphasizes that consumers may not be as knowledgeable about their automobiles as they think.

CARbonga is an iPhone app (also runs on the iPod touch and iPad) designed to address both broader vehicle safety systems, such as its anti-lock brakes, air bags, safety-restraint systems and tire pressure monitoring systems, as well as On-Board Diagnostic (OBD) codes for vehicle emissions and other engine problems.

“Our survey shows that 80% of consumers know something could be amiss with their vehicles, even though the warning lights do not indicate a problem. Still, 81% said they trust their automobile manufacturer and/or their auto’s electronic system to warn them of problems,” said Rich Parlontieri, president and CEO of Speedemissions, Inc. and founder of CARbonga, who added, “That’s a potentially dangerous gamble.”

One version of CARbonga allows car owners to receive notices from the vehicle manufacturer about possible warranty work and notice of issued TSBs through their iPhone.

From April 2008 to April 2009, more than 6,300 Technical Service Bulletins (TSBs) were issued to dealers by automobile manufacturers. Parlontieri said this is a key issue, given that 38% of car owners surveyed did not know dealers and automotive repair shops routinely received these TSBs.

Numbers Up

According to the National Highway Transportation Safety Association (NHTSA), 16.4 million vehicles were recalled in 2009, an increase of 56% over the previous year. The trend toward increases in recalls each year could create anxiety among vehicle owners.

However, a rise in auto recalls may not necessarily be due to poor OE workmanship, says one auto information provider.

Rather, it’s just the outcome of more vigilant drivers.

While new car recalls have been among the biggest news stories of the year, an analysis by Edmunds.com, assures consumers that despite these recent headlines, recalls were much more of a concern in decades past.

“Recall numbers have been remarkably high since the mid-’90s when car technology really began getting complicated, but this year they’ve been far more publicized,” asserted Edmunds.com senior analyst Ray Zhou, PhD.

“Thanks to recent headlines this year, drivers are more alert to any potential safety issues and more likely to report any potential flaws and perhaps even pay closer attention to recall news,” he said.

Through early June, Edmunds.com contends that the industry has issued 81 recalls, which is in line with the recent average of 164 per year.

The number of vehicles affected by the recalls this year – just over 10 million to date – suggests that the year-end total may be slightly higher than the 10-year average of 18.1 million vehicles per year.

“The level of vehicle recall activity simply doesn’t suggest any greater reasons for concern by consumers,” said Dan Edmunds, Director of Vehicle Testing at Edmunds.com.

“In fact, automakers as a whole have become increasingly diligent, not only about safety and reliability, but also about reporting problems with their vehicles and, in many cases, recalling them more quickly than in the past.”

As drivers become more attentive about vehicle problems and TSBs — either through new technology applications or through the news — it will be interesting to see if this translates into more scheduled shop visits by your customers.

Ed Sunkin is an author for autocarepro news. You can email Ed at esunkin@babcox.com.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

Does the use of ethanol reduce fuel economy relative to conventional gasoline?

Yes. The consumption of fuel relative to miles/kilometers traveled is directly related to the energy content. Conventional gasoline has an average energy content of 114,000 BTU/gallon. But, energy content of conventional gasoline can vary up to 7 percent from one fill up to the next!

Ethanol alone has a value of 76,100 BTU/gallon. So, E10 fuel—conventional gasoline blended with 10 percent Ethanol—will give a value of about 111,000 BTU/gallon, or a 2.6 percent reduction from conventional values. That’s low enough that the average driver may not see a decrease in fuel economy.

E85 fuel

Conventional gasoline blended with 85 percent ethanol—is a different story. E85 has an average energy content of 81,800 BTU/gallon. A vehicle using E85 would require 1.39 gallons to go the same distance as one gallon of conventional gasoline. In other words, the average driver will notice a difference in the thickness of his wallet after switching from conventional to E85 fuel.

But it’s not the worst; other alternatives such as compressed natural gas (CNG) have a value of only 75,000 BTU/gallon. That means it would burn 1.52 gallons to go the same distance as one gallon of conventional gasoline!

Can any vehicle use ethanol-containing fuel?

No. Older vehicles have fuel systems containing plastics, elastomers and metal alloys that may not be compatible with ethanol. In order to be compatible with ethanol-containing fuel, special fuel system hardware, sensing mechanisms and algorithms in the on-board computer are necessary to make adjustments to the fuel/air ratio.

But, every gasoline-powered vehicle manufactured since the early 1980s can use up to E10. However, above 20–30 percent ethanol, the computer in non-flex fuel vehicles cannot make the adjustment and a lean fuel/air mixture will result.

E85 fuel can only be used with flex fuel vehicles specifically designed for operation on fuel with high levels of ethanol.

Can ethanol-containing fuel affect cold starting?

Yes. For example, on a cold winter morning in Minnesota, an E70 fuel will start a vehicle only because 30 percent of the fuel is a volatile fuel fraction. But, E85 fuel may cause significant starting problems and a vehicle with E100 in the fuel tank may not start on a cold winter morning in Northern climates.

Does ethanol-containing fuel dry the fuel system?

Yes. Ethanol used for fuel blending is anhydrous—contains no water. Refineries typically do not mix ethanol with fuel because pipelines contain a significant amount of water.

E10 fuel can hold a limited amount of water, which is highly temperature dependent, before the fuel experiences phase separation (turns cloudy) and a large percentage of ethanol and water settle to the bottom of the vehicle’s gas tank. If this happens, the vehicle will run very poorly.

One solution is to add a relatively large amount of BG Fuel System Drier, Part No. 280, to the tank. Raise the temperature of the fuel to around 70°F in a warm garage. Slosh the fuel in the tank to promote mixing. And, hope the temperature remains warm enough so the fuel can be used before the next cold spell.

Or…drain the water/ethanol mixture from the bottom of the tank.

Can ethanol-containing fuel cause fuel-filter plugging?

Yes. If a fuel supply system is switched from conventional gasoline to E10 or E85, much of the sediment, oxidation residue and other contaminants in the storage tanks and lines are dissolved or suspended in the new fuel. These contaminants may find their way to the filter until a sufficient amount of the ethanol-containing fuel has been turned over. Ethanol-containing fuel also contains water, which carries dissolved salts and contaminants, and can cause premature filter plugging and injector fouling.

But, if the fuel storage and delivery system are clean and well maintained, no additional filter plugging should occur—outside of what is typical for conventional gasoline.

Can ethanol-containing fuel cause engine deposits?

Yes. E10 fuel is the worst blend in terms of deposit formation. It can create significantly more deposits than conventional gasoline. Oddly, E85 fuel is generally considered better than conventional gasoline in terms of deposit formation. But solubility problems have been linked to the type of detergent additive used in E85 fuel. These detergents would be the types typically found in conventional gasoline (e.g., polybutene amine). Polyether amine, such as that found in BG 44K,® have been shown to be stable in ethanol-blended gasoline.

Can ethanol-containing fuel corrode the fuel system?

Yes. Ethanol is a mildly acidic molecule. Acids accelerate the corrosion process, particularly in iron-based alloys. But it can accelerate corrosion to aluminum, brass, bronze, silver, lead and other alloys found in the fuel system.

Protect the fuel system by neutralizing acids in the fuel with an amine-based dispersant, such as polyether amine, and adding corrosion inhibitors—BG CF5® and BG Supercharge® II.

Does ethanol-containing fuel help reduce emissions?

Yes. Denver was one of the first cities to mandate the use of E10 fuel to improve air quality in 1988, and the program was very successful. As a result of this study, many cities have adopted E10 gasoline, some mandated by the Clean Air Act.

The EPA mandates that states and/or municipalities maintain monitoring stations in the containment areas and specify an upper limit of 35-ppm carbon monoxide for a one-hour period and 9-ppm carbon monoxide for an eight-hour period. Monitoring stations are allowed only one exceedance of the air quality standard per year.

Are fuel retailers required to label pumps that contain ethanol?

Yes and no. The federal government is not involved unless the concentration of ethanol is above 10 percent by volume. But, many states require labeling.

Are boats, small engines and recreational vehicles prone to problems with ethanol-containing fuel?

Yes. Many vehicles and engines in this category were not engineered to use ethanol-containing fuel until after 1990. Problems are not inevitable but there’s a much greater chance of issues such as corrosion of fuel system components and deterioration of fuel lines and gaskets.

Fiberglass tanks on boats manufactured before 1991 are particularly vulnerable to deterioration with the use of E10 fuel. Recreational vehicles typically go unused for extended periods of time and can draw water into the fuel tank, which will significantly aggravate the problem. Ethanol-containing fuel can also be significantly more oxidatively unstable compared to conventional gasoline. With the vehicle sitting over the winter months, ‘sour’ fuel can result in gummy deposits and an engine that will be very difficult to start the following spring.

Naturally, the marine industry and small engine manufacturers are mostly against raising the limit on the maximum allowable concentration of ethanol and would prefer laws mandating the labeling of ethanol concentration at the retail pump.

What can BG do to help?

BG Products can help prevent the negative aspects of renewable fuels such as ethanol. BG Supercharge® II and BG CF5® have effective multi-metal corrosion inhibitors, anti-oxidants and polyether amine technology to prevent the kinds of problems described above. Both products are highly recommended for the marine, small engine and recreational vehicle market.

Add BG 44K® to quickly remove the deposit formations caused by the use of E10 fuel. BG MOA® helps neutralize the combustion acids and corrosive effects of ethanol in the crankcase and upper cylinder area plus provides excellent anti-oxidation protection.

E10 fuel accelerates deposit formation on rings. And, stuck rings not only cause excessive oil consumption, but also allow oil to enter the combustion chamber and soil spark plugs and sensors. Use BG Compression Performance Restoration, Part No. 109, at oil changes to prevent ring sticking and improve effectiveness of emission control systems.

This article has been reprinted from the Fall 2009 issue of the BG Blend’r newsletter, visit BGprod.com to learn more about BG Products, Inc.

Communicating with a vehicle’s on-board diagnostic system is essential when trying to diagnose transmission problems. And the way to do that is with a scan tool, a device that gives the eyes needed to determine the appropriate diagnostic approach. Although the tool may provide both information and bidirectional control, the data retrieved still needs to be processed and interpreted.

To make full use of a scan tool, one must understand all the abilities and options it has to offer. No one should expect a generic scan tool to be equivalent to a factory scan tool. The former offers coverage over a broader range of manufacturers, while the latter is designed with a focus on the needs of a single manufacturer. The trade-off is obvious: The manufacturer’s specialized scan tool can do more but covers only that manufacturer’s vehicles, while the generic scan tool may have fewer functions but covers more vehicles. Since most shops work on a slew of different makes, a generic scan tool becomes a necessity.

One of the challenges for a scan tool manufacturer is…

To continue reading, check out the original article from Motor Magazine at www.motor.com.

Have you ever had a problem properly diagnosing vehicle transmission related issues due to constantly varied scan tool parameters and procedures? Check out AVI’s Automatic Transmissions Diagnostics class with Wayne Colonna and get answers to some of the most difficult transmission related problems, giving you solutions and demonstrations on how to properly diagnose these issues utilizing aftermarket scan tools.

Nearly every time I look at an alternator it conjures up fond memories of growing up in a family-owned auto electric shop. In the 1980s, Chrysler pioneered voltage regulation with an engine control computer on its first EFI systems. Chrysler still uses a similar method of voltage regulation today. Quite a few years later, Ford followed with a powertrain control module (PCM) connection to the alternator. Not to be outdone, GM and others joined the ranks of OEMs using some form of strategy to tie engine management and voltage regulation together.

Although the image of a full field test with a pocket screwdriver making sparks in the D hole of a Delcotron is outdated, simple tests for outsmarting today’s socalled smart charging systems are out there for the tech who’s willing to learn what makes these latest systems tick.

To keep this smart charging system visit manageable, we’ll focus on GM passenger cars and light-duty trucks. Before we venture too far out into the deep water on the latest charging systems, let’s do a bit of review. Not a bad idea considering that many techs reading this have never seen the inside of an alternator, as the art of rebuilding has becomes a thing of the past for most shops.

The primary missions for any alternator are to maintain a charge on the battery and keep up with the vehicle’s electrical accessory demand. To accomplish these tasks, a rotating electromagnetic field called a rotor induces an electrical charge into three windings that are 120° out-of-phase. These windings (the stator) create alternating current that in turn is rectified into direct current by a set of diodes in the back of the alternator. Pretty basic stuff, right?

The job of the voltage regulator has always been to control the amount of electrical energy (field current) in the rotor via electrical power supplied to the brushes on the rotor’s slip rings. The greater the current supplied to the slip rings, the more voltage (and current) the alternator puts out. As electrical loads such as the headlights, blower motor or rear defogger are added, the regulator senses a reduced voltage and applies more power to the rotor, allowing the alternator to keep up with the electrical demand. When the regulator fails, it usually causes one of two problems: Either the rotor does not receive power and there is no charging output, or the regulator gives full power to the rotor and the alternator puts out too much voltage, boiling the battery dry and burning out light bulb filaments.

Then and Now

To understand where we are now, it’s important to know where we’ve been. Historically speaking, the description just given is pretty much the way it’s been since voltage regulators moved off the firewall and into the back of the alternator in the 1970s. These fundamentals have changed very little until the last five years for GM. One change with voltage regulation did take place in the mid-’80s. It was found that as engines became smaller and developed less torque, the sudden reaction to an increased load on the accessory drive belt sometimes caused a rough idle/vibration, or even engine stalling. Power steering pressure switches and a/c compressor request/control circuits all helped with idle quality, but there was nothing to tip off the engine management computer that an increased load was occurring from the alternator’s varying field current.

Every tech has heard an engine bog down when the alternator’s output ramped up in response to increased electrical load. Faraday’s law of induction tells us why this occurs, but that doesn’t help the PCM with engine management. Engineers came up with the solution and the four-terminal voltage regulator was born in the late ’80s. This change caused confusion that has lasted until the present day, due to the variations of systems using one or more of those four-terminal regulators. The letters P, L, F and S were stamped on these regulators to identify the terminals.

Unlike SI (series integral) alternators with the older two-wire regulators, the newer design CS series alternators eliminated unmanaged load dump (fast field ramp-up) that caused the rough idle and stalling issues when the electrical loads were suddenly turned on. These CS series machines gradually ramped up their fields with a 400Hz pulse-width modulated (PWM) output from the regulator to the rotor’s brushes. No more stalling and no more vibration when the accessories were all turned on.

Of the four terminals, the P terminal was seldom used with the exception of some diesel applications. The P stands for “Phase” and is the output of one leg of the three stator windings, giving a tach signal to a diesel engine controller. The L stands for “Lamp” and goes exactly to where you might think it would—to the charge lamp indicator. The F stands for “Field” and provides a square wave to the PCM, allowing it to know the field strength (torque demand) of the alternator. On some models the third terminal is marked I for “Ignition” and acts as a backup for regulator turn-on voltage should the bulb in the cluster fail to provide voltage to the L terminal. The S stands for “Sense” and is connected to a location in the wiring harness where accessory current draw is high, such as a fusible link at the starter or a bussed electrical center. While many vehicles used only one wire (the L terminal), there were quite a few that populated the regulator’s connector with two or three circuits, and this led to a major source of confusion that still exists today! Which of these circuits is really needed when performing simple diagnostics? The answer is, in almost all cases, the L terminal.

Test Light or Lab Scope?

That’s enough theory; now on to something practical! If you’re working on a GM product, whether it’s a 1989 or 2004 model, you can determine with a simple test whether a charge problem is due to a defective alternator or a problem with one of those four wires going to the regulator. With a voltmeter connected to the battery, simply disconnect the voltage regulator, then start the engine. Next, connect the alligator clip of a conventional test light (not the newer LED style) to a nearby source of battery positive. Finally, touch the test light probe to the L terminal of the voltage regulator, as shown in the photo at left. Your test light will do the job of the cluster’s charge light.

When the alternator is not charging, that L terminal will be grounded (the test light will glow), and when it is charging, the light will go off. The reduced voltage provided by the test light will provide the necessary excitation signal for the regulator to come to life. Note: If the regulator connector is in a difficult location, use a short jumper lead to do the job. If the alternator “sings” and your voltmeter jumps up to show charging voltage, the alternator is likely good and you must move your focus to the wiring leading to the regulator connection. If it doesn’t start charging, the alternator is definitely bad and it’s time to sell a new or reman unit to the customer.

I said the alternator is “likely good” if you touched the test light probe to the L terminal and it began to charge. I left some wiggle room here because not all four-wire GM voltage regulators are created equal. Some aftermarket alternator rebuilders try a little too hard to reduce their part numbers to a leaner inventory, creating alternators that charge but may not charge properly. Without going too deep into that, I’ll just say that GM had good reasons to use one, two, three or all four of those regulator terminals, so the one-size-fits all reman part may give you grief.

During the late ’90s, we started seeing the L terminal on the CS series four-wire regulators connected to the PCM, as well as the F terminal. This led many techs to assume that the PCM controlled the field current, as it does with Chrysler. It does not. It does provide a signal to the L terminal for exciting the regulator and does receive a ground on that circuit when the engine is stopped or the alternator has failed, just as before when the circuit was connected to the charge lamp in the cluster. The difference now is this PCM connection to the regulator’s L terminal can inhibit sending the excitation signal to that circuit, which would prevent the alternator from charging.

Why would it do that? It does so to delay the introduction of field current into the rotor during engine start-up. Remember Faraday’s law? Improved starts occur when an engine doesn’t have to deal with an alternator load on its drive belt. After the engine starts, the PCM uses the circuit leading to the regulator’s L terminal as an input. If it sees a ground on that circuit, such as when the alternator senses a problem internally, the PCM then sends a serial bus message to the cluster requesting the charging indicator to come on. Most scan tools can read the PCM PIDs for the L terminal status and the percent of duty cycle the PCM sees coming from the F terminal. You can also scope the F and L terminals to watch the regulator ground the voltage pulled up by the PCM on the L terminal and observe the 400Hz signal on the F terminal displaying the duty cycle that the rotor winding is receiving (see Fig. 1).

Now We’re Getting Complicated

If the CS series of GM alternators weren’t smart enough for you, we have the latest systems called Regulated Voltage Control (RVC) showing up on the scene in the mid 2000s. Why a new system? Batteries are sensitive to temperature. The lower the battery’s temperature, the lower its chemical and electrical reactivity. This means the battery puts out less voltage in cold temperatures and needs more voltage to charge. Conversely, a battery puts out more voltage and needs less voltage from the alternator in warm weather.

While Chrysler did indeed use an external temperature sensor to sense battery temperature for its PCM-controlled voltage regulation, GM always used a thermistor built into the voltage regulator to sense underhood temperatures for charge rate compensation. These days, with battery locations spread out everywhere from the engine compartment to the trunk to the back seat, a better way of detecting and compensating for battery temperature had to be developed to replace the temperature sensing that traditionally occurred within the voltage regulator. Keeping batteries charged with just the right voltage and maintaining greater than 80% state of charge (SOC) helps them last longer.

Shedding Some of the Load

Helping the battery achieve the SOC goal has been the job of another smart charge feature called load shedding that has actually been around for well over a decade. The alternator’s pulley turns slower when the engine is idling, causing less output. When idling with a heavy electrical accessory load applied, the alternator may not be able to keep up, and the voltage to the battery drops below 12 volts. If this continues for very long, the battery can drop below the desired 80% SOC. Load shedding has been a function of the body control module (BCM) in both the older CS series alternators (four-terminal regulator) and the newer Regulated Voltage Control (two-terminal regulator) systems.

Load shedding basically is a function of the BCM or another module on the serial bus (Power Mode Master) watching battery voltage and doing something about it if it gets too low. The process involves first requesting the PCM to boost idle speed to raise the alternator’s output enough to keep up with the heavy accessory demand and still trickle a charge into the battery. If the first idle boost doesn’t do the trick, subsequent idle boosts are commanded before a more aggressive action is enabled—reducing power to certain power-consuming accessories, such as the rear window defogger grid.

Regulated Voltage Control Explained

Regulated Voltage Control uses information from the battery current sensor, calculated battery temperature and system voltage to determine what the perfect voltage to supply the battery with is. In addition to nurturing the battery into longer life by maintaining proper state of charge, RVC allows the charging voltage to drop below the 13.8 to 14.8 volts to which we’re all accustomed. If the battery can maintain an 80% SOC with 13 volts at a particular temperature, why would we want to charge it at 14.8 volts? Higher voltage comes at a price of increased drive belt load. Every bit counts with today’s fuel economy goals. Additionally, light bulb life is increased with a slightly lower charge voltage. Depending on the model and year, the newer GM RVC charging systems may include up to nine different charging rates strategies, among them:

Battery Sulfation Mode. No sense hammering a battery that has given up the ghost!
Start-Up Mode. Gets the battery back up to greater than an 80% SOC quicker.
Fuel Economy Mode. Alternators that put out less voltage help engines use less fuel.
Headlamp Mode. Okay, it’s time for a little more voltage now that the lights are on.

Referring to the RVC graph in Fig. 2, you can see how much thought has gone into tailoring the alternator’s charge output to suit various scenarios. An interesting sidebar note would be the ramp-up in field current that the RVC systems sometimes introduce on deceleration. When you’re cruising in Fuel Economy Mode (lower charge voltage), you can charge harder during a brief period of deceleration without sacrificing fuel economy or overcharging the battery. In fact, when there’s a greater alternator load on the engine during deceleration, that load contributes to engine braking—something that’s good for brake pad life as well. Think of this as a mild form of what hybrid vehicles do with regenerative braking.

Speaking of hybrid vehicles, DC-to-DC converters (high voltage in, conventional 14 volts out) come online whenever hybrid systems are powered up. This may occur with the key on and the engine off. The DC-to-DC converter receives serial bus messages from a BCM or PCM on the vehicle responsible for the equivalent of RVC functions. This allows a hybrid vehicle’s DC-to-DC converter to tailor a perfect charge rate into the vehicle’s 12-volt battery.

RVC Operation & Diagnostics

To be clear, GM’s RVC systems use alternators with field currents that truly are controlled by logic external to the alternator. You’ll see two things right off the bat on RVC vehicles tipping you to the presence of this latest technology: First, you’ll see a two-wire voltage regulator connection instead of the familiar four-wire connection. Second, you’ll notice a funny-looking sensor or module wrapped around either the negative or positive battery cable. It may remind you of an inductive current probe, because that’s what it is.

There are two types of these systems—stand-alone RVC (SARVC) and RVC. The former was used for a few years (mid-2000s) on light-duty trucks and SUVs. The current sensor in the SARVC system is built into a full-fledged electronic module complete with a Class 2 serial bus circuit to receive and transmit information. You probably won’t find the data PIDs for this system in the PCM. The SARVC module is also known as a generator battery control module (GBCM) and is located within a list of body modules on the scan tool. Not all aftermarket scan tools can read this module, but they will display PIDs like Battery Voltage, Battery State of Charge, Regulated Voltage Control Current and Generator L Terminal Signal as a percentage.

The RVC systems use a Hall effect type current sensor that sends a PWM signal at 128Hz to the BCM. This sensor stays powered up long after the ignition switch is turned off. The reason is that this sensor also reports to the BCM any news of excessive parasitic current draw. This is also a scan tool PID—nice to know when diagnosing a battery rundown problem on a RVC-equipped GM vehicle. And speaking of PIDs, since the BCM is the module in charge of logic for this system, you’ll find up to 20 PIDs under a heading titled Charging Info when searching for charging system PIDs within the BCM. Although the BCM is the “brains” for the non-stand-alone RVC system, it’s the PCM that actually carries out the commands to control the L terminal with a PWM output to control the alternator’s charge rate. To find output PIDs, go into the Powertrain section on your scan tool. You may encounter output PIDs in the section of the PCM titled Electrical/Theft. As with earlier non-RVC, four-terminal CS series alternators, the L terminal can be commanded on and off by going into the PCM and selecting output control.

On RVC vehicles, you’ll see the charge voltage fluctuate while driving or even while running the engine in the bay. The changes will be subtle, as the rate of change varies from 10 to 20mV per minute. Charging rates as high as 15 volts are observable on some vehicles, depending on current demand and battery SOC, along with values as low as 12.9 volts. The PWM signal from the PCM to the L terminal on these twowire regulators varies from 10% to 90%, with the latter being the higher voltage command (15.5 volts). If this circuit goes open, the default charge rate from the alternator is 13.8 volts.

One way to outsmart the smart charging system is to disconnect the current sensor or SARVC module. On some systems you’ll see 15.5 volts with the engine running and a light electrical load applied. This should tell you if you’re dealing with a good, old-fashioned alternator problem or a vehicle wiring or module problem. Naturally, DTCs will be set that will have to be cleared. Don’t forget to look in the Body Controls section of your scan tool when clearing codes, in addition to the PCM.

But no matter how complex these systems seem, it all really comes down to a battery, an alternator and some modules monitoring and controlling voltage regulation. By knowing how these new systems work, you can keep outsmarting the latest smart charging systems that show up in your bays!

This article can be found online at www.motormagazine.com.

There are some obvious questions that you may ask. Should I get involved with TPMS? Should I invest in the tools and training? What will it mean to my business? For the purpose of this article, we are going to assume that you have dealt with many of these questions and you are at the point of taking on this opportunity and now question whether or not you need a TPMS Tool.

Before I answer that question, let’s consider three important points. First, know that there nearly a quarter of a billion TPMS Sensors currently in use. Better than a third of those are at least 3 years old. Even more there are a large number of sensors that are on wheels that are ready to have the tires changed. There is a growing population that very soon will have battery issues. The bottom line is, if you haven’t already, you will soon have TPMS vehicles in your garage or repair facility.

Secondly, you need to understand the types of re-learn procedures that you face. 25% of the vehicles have a Stationary method. The Stationary re-learn requires an activation tool and the car to be in a special re-learn mode. A series of key cycles or button pushes will put these cars into learn mode so you can then use an activation tool to trigger the sensors and program the sensor ID’s into the control module. The challenge this method presents is the need to know all the different methods to get the car into learn mode.

Some vehicles can “auto-learn” or “self learn” new sensor ID’s. Essentially by driving the car after replacing the sensor, the car will assume a new ID is present after a pre-determined number of consistent transmissions from the sensor. The big issue here is time and driving. You can either drive your customer’s car until the light turns off or send your customer away with the light on, without knowing for certain that the light has gone off.

The last method requires an OBD Connection. Theses re-learns require that the sensor ID’s be programmed to or “written to” the TPMS control module directly. This is typically done with a Scan Tool or a COMBINATION Activation/Scan Tool. This method closely resembles the process used at the auto assembly line. Sensor ID’s are captured directly by activation (TPMS tool) and then connected to the OBDII port to write them (scan tool). This is the preferred method of re-learn as it is accurate and fast!

Finally, you need to know that your competitors are buying into this technology. Whether your competition is an OE dealer or another automotive service facility, they have the necessary tools to properly service TPMS vehicles. You can ill afford to let your competitors have the “leg up” on this emerging service. Having the ability to “turn out the TPMS light” will not only give you the ability to keep your customers happy but more importantly keep them from going to your competition.

So the answer to the question on whether or not you need a TPMS tool is simply yes. The majority of cars and trucks with TPMS require at a minimum an activation tool. A growing number of vehicles need a combination tool to get the ID’s programmed to the car. The best solution is a combination tool that handles all three types of re-learn situations, using the same process. A Bartec sales rep can tell you more about such tools.

Scot Holloway is the General Manager of Bartec USA, LLC. Bartec USA and the Bartec Group of companies have long been experts in TPMS. With over 80 TPMS installations worldwide, Bartec programs the TPMS of all varieties of makes and models. Currently, Bartec brings this level of expertise and understanding to the complete range of aftermarket TPMS tools. Please visit www.bartecusa.com for more information on Bartec USA and Bartec Auto ID.

Just like your cable TV, as a signal is sent down the wire from one communication device, there needs to be another at the other end that can “descramble” that information and turn it into readable information. These “lines” are generally referred to as BUS lines, or Data lines. 

Most of the time they are in pairs of two wires that are twisted together (less radio frequency (RF) interference). Some manufacturers use a two-speed CAN.

One line is for low priority information, such as radio, windows, etc. A second, faster speed line is for things like transmission, theft, etc. Both systems move along the same wires at the same time.

What each of the “modules” that are on the BUS line do is use the information that they are programmed to read, any other information on the BUS is ignored and not read by that particular module.

What to Expect

These CAN systems are not going to go away. They’re with us for now and most likely will be even more complicated in the future.

Scanning is the key to working with these systems. A proper scanner, and not just a “code reader,” is the necessary tool to see these “TV” channels on your little screen (your scanner). A dealer-equivalent scanner is the best way to “look” at these systems. Mode $06 is another option, but one thing you don’t want to do any more is stab a wire with a test light looking for current or ground… it’s not there.

Imagine stabbing your test light into your cable TV line. What do you think you would find there? You wouldn’t find anything that a test light would help with. Also, I don’t advise sending voltage or a solid ground down a data line. Would you try that with that coaxial cable coming into your house? I think not!

My advice when it comes to diagnosing power windows, gauges, or for that matter just about anything these days, is to get your scanner out and look for codes, look for a class 2 serial data line on your GM, read the mode $06 information, or whatever that particular manufacturer is calling their CAN line information.

These data information screens will give you the clues as to what to be looking for. The next stop is to go to your PC and look up the wiring diagrams. Codes are only a starting point. Remember, you still have to diagnose the cause of that code and what it means.

Example: 2003 Cadillac DTS

The problem with this car was with the window circuits. If the driver’s side window switch was pushed, the driver’s window and the passenger front window would go down simultaneously and would go up the same way. If you tried the front passenger window switch, nothing happened at all. Using the driver’s side rear window switch from the driver’s door switch would operate both the rear windows up and down together exactly like the front set. The car was clean, well kept and had no signs of any recent damage. As far as the owner knew, there was nothing out of the ordinary that might be a hint to possibly explain this strange window fiasco.

Scanning the car led to several history codes that could be related and some codes that couldn’t be related to the problem, that is until I went to the Class 2 serial data line information. It listed where the trouble was at… corrupted information and loss of communication on the BUS. Looking at the four door modules showed that the scanner couldn’t communicate with either passenger side modules. Using the scanner to operate the windows without having to move the switches showed no difference between the scanner and the actual window switch operation from the driver’s door.

Pulling the wiring diagram, it showed that the serial data lines ran from door to door and back to the BCM. There were no obvious wiring issues to be concerned with, but I did notice several slight whitish droplets dried onto the inside of the door. It looked to me like “Bondo” or sanding dust mixed with water. But, the owner knew nothing of anybody work ever done to the car. Opening the FPDM and examining the circuit board showed no water damage. With the data lines showing no communication with the modules and the wiring looking perfect, the next best thing was to change the FPDM and RRDM (Front Passenger Door Module, Right Rear Door Module).

It worked like a charm. After replacing the modules, I went back into the scanner to see if the communication had been restored. Sure enough it was, another job out the door.

I never picked up a test light like I would have on an older car and I didn’t have to pull out the old trusty tap hammer and start banging around till something moved. Using the scanner and the CAN lines showed where to go to make the repair.

History Lesson

In 1983, Bosch Corporation introduced the CAN system to the world as a preparation to what they saw as an increase in the automotive electrical system advancements. In 1987, the first CAN system was officially called “CAN,” but it wasn’t till 1992 Mercedes Benz that a CAN system was accepted as the true first CAN system. Early GMs had a system that could have been called CAN back in 1987, but the only references were to call the lines “data lines.” It still worked about the same way but wasn’t diagnosed the same way as we do today.

In 1995, GM introduced Class 2 serial data lines which run at a speed of 10.4 kbps. In 2004, GM went to their next generation system called GMLAN (local area network) which had a two-speed system: low 33.3 Kbps and a high at 500 Kbps. Mercedes Benz uses several BUS lines; on one car I counted 5 different CAN speeds.

With the speed and flexibility of these electronic systems the manufacturers can create in today’s cars, I can only imagine how far all this information is going to go. At some point in time, that wiring will be a thing of the past too. Everything in the car could someday go completely wireless; modules will get smaller, faster and less likely to fail. Scanning could be done without even seeing the car in a repair shop. Just dial your cell phone to your shop of choice and a complete diagnostics could be done right then. I know it sounds a little “out there,” but just imagine what a mechanic from the 50’s would think of today’s cars.

Scott “Gonzo” Weaver is the owner of Superior Auto Electric in Tulsa, Okla. and has owned the shop for 27 years. He was given his trademark nickname “Gonzo” while serving in the USMC. He is the author of the book “Hey Look! I Found the Loose Nut,” that can be purchased online at Amazon.com or at www.gonzostoolbox.com. Email him at Gonzosae@aol.com.

CAN BUS Tech Tip: Diagnosing Malfunctioning Jeep Instrument Cluster

The same two-wire CCD BUS that Chrysler has been using for years on its cars is now being used on Jeeps and trucks, giving today’s Jeep Wrangler a new level of sophistication.

On these vehicles, the BUS bias voltage is produced by the printed circuit board or instrument cluster. As with all CCD BUS circuits, the wires are twisted together in the wiring harness with 2.5 volts on each wire. Some manuals show BUS + or BUS – for each wire, but both wires have 2.5+ volts on them, so be sure to check each wire individually to ground with a DVOM. A range of 2.3 to 2.6 volts is normal, though it may vary a bit when the system is awake.

If the instrument cluster doesn’t work, first determine which gauges don’t operate or if the whole cluster is down. I like to start testing with the printed circuit board self test.

Check your manual for the proper procedure, as they may vary somewhat

1. Put the key in the unlock position — the next position up from lock. (Lock is where you can remove the key.)
2. Depress and hold the trip reset button and turn the key to the on position, but do not start the engine.
3. Release the trip reset button and the tests should start.
4. All the gauges and related lights will operate through their paces in two-second intervals. If none of the gauges operate, check the powers and grounds at the instrument cluster. You’ll need to rerun the test if you missed any gauges. If any of the gauges don’t actuate, then the instrument cluster is defective.

If all the gauges appear to work normally with the self-test, move on to the BUS operation from the data link connector (DLC) under the dash. Check for the 2.5 volts on each wire. If the voltage is off on one or both wires, unhook modules on the BUS one at a time while monitoring BUS voltage. When the voltage returns to normal, you’ve found your culprit. If all the modules are unplugged and the BUS voltage is still off, separate the connector near the instrument cluster to test the BUS voltage straight out of the printed circuit board. If the voltage returns to normal, there’s a problem with the wiring harness. If it doesn’t, a bad instrument cluster is the problem.

Written by Michael Brown, IDENTIFIX DaimlerChrysler, Mitsubishi, Hyundai Specialist. He is certified ASE Master + L1. He has 22 years of diagnostic and repair experience.

For more information, visit www.identifix.com.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

What many motorists don’t know is that their A/C system works year round, not just during the hot summer months. On most late-model vehicles with automatic climate control systems, the A/C system ­cycles on and off as needed to dehumidify air entering the passenger compartment. This helps clear the windshield and prevents the other windows from steaming over, as well during cold weather.

One clue that something may be amiss with the A/C system, therefore, is poor ­defroster performance. If air is blowing out of the defroster ducts on top of the instrument panel but the defrosters are slow to clear the windshield, the A/C system may not be dehumidifying the air. The problem could be low refrigerant due to a leak, a weak compressor that is not developing normal system pressure, or a control problem with a switch or sensor.

A/C problems can occur any time of year, not just during the hottest days of summer — though that’s when motorists are most likely to notice poor cooling performance from an A/C system. Many will put off needed repairs as long as the weather is tolerable. But give them a few hot days of sweltering heat, and their resistance will melt like butter in the hot sun.

A/C RECHARGING

The DIY market for A/C parts still exists, but mostly for simple tasks such as recharging a leaky A/C system with additional refrigerant. More ambitious jobs include replacing leaky hoses or seals, or a bad compressor. Diagnosis is often the biggest challenge, especially if the cause of a no-cooling problem is not obvious. Is it the refrigeration circuit, an electrical problem or a control issue? Difficult cooling problems and repairs are best left to an A/C professional.

Adding refrigerant to an A/C system is fairly simple. First, you locate the low-pressure service port, which is typically on a hose or the accumulator ­toward the back of the engine compartment. You then connect a service hose and valve to a can of ­refrigerant. The valve is turned to puncture the top of can, which allows refrigerant to flow into the hose (this is necessary to displace air inside the hose).

The service hose is then attached to the quick-connect fitting on the low-pressure service port.

To get the refrigerant to flow into the system, the engine must be started and the A/C turned on. The compressor will then pull refrigerant through the service connection into the system. After several minutes, all of the refrigerant should have been pulled from the can into the system. At this point, the service hose can be disconnected and another can of ­refrigerant can be added to the system if it still needs more refrigerant.

The amount of refrigerant in an A/C system is critical for proper operation. An overcharged system will not cool efficiently, nor will a system that is low on refrigerant. Many late-model A/C systems have very small refrigerant capacities (only a can or two), so one has to be very careful not to overcharge the system.

A gauge set that connects to the high- and low-pressure A/C service ports is essential for accurate charging. A professional gauge set or a recharging station weighs the refrigerant as it is added to the system.

LEAK REPAIRS

Adding refrigerant to an A/C system will often ­restore normal cooling, provided the compressor, control valves, sensors, switches and condenser fan are all working properly. But if the A/C system has a leak — and the leak is not found and repaired — sooner or later the new refrigerant will leak out and the system will stop blowing cold air again.

R-134a contains no chlorofluorocarbons (CFCs) so it won’t harm the ozone layer as R-12 did. However, ­R-134a is a greenhouse gas that can contribute to global warming. R-134a retains heat 1,300 times more than carbon dioxide, which is currently a hot environmental topic as governments look for ways to minimize CO2 emissions.

There is still considerable debate over the impact manmade CO2 and other gases are having on average global temperatures and weather. A pound or two of refrigerant leaking out of a car’s A/C system over a period of several months isn’t going to bring about the end of civilization as we know it. But the combined effects of zillions of ounces of refrigerant leaking from ­zillions of vehicles all over the planet could have a measurable impact on global warming.

The point here is that anyone who is buying R-134a refrigerant in small cans probably has a leaky A/C system. A late-model vehicle should not leak more than a few fractions of an ounce of refrigerant a year. If it can’t hold a charge from one cooling season to the next, it has a major leak that needs to be diagnosed and repaired.

Refrigerant leaks can be found in one of three ways. A visual inspection of the A/C compressor and system hoses should be made to look for “wet spots” left by compressor oil that has leaked out with the refrigerant. If a system is leaking refrigerant, it will also be leaking compressor oil. The most likely places to look for leaks are at the hose and pipe connections, and the A/C compressor shaft seal.

Another method for finding leaks is to look for telltale dye stains on system hoses, the compressor and condenser. Many late-model vehicles are factory-filled with refrigerant that contains colored dye. The dye is typically yellow or green, and gives off a fluorescent glow when illuminated by an ultraviolet (UV) light.

If the A/C system does not contain dye, a small dose of dye can be added to the system when it is recharged. Or, refrigerant that already contains dye can be used to recharge the system. It may take a few days of operation before the leak shows up, but sooner or later it usually will — unless the leak is in the evaporator inside the HVAC unit under the dash. Leaks here are essentially invisible because the evaporator is buried and can’t be inspected directly. For these types of leaks, an electronic leak detector is often needed to sniff out the escaping refrigerant.

Some motorists are of the mindset that it’s cheaper to keep adding refrigerant than to fix the leak. This approach may get them though the hottest days of summer, but as was explained earlier, you need A/C year round for dehumidification and defrosting. What’s more, a leak that isn’t fixed can cause bigger problems down the road — such as a possible compressor failure or internal corrosion that ruins other expensive parts such as the condenser or evaporator.

The way to permanently fix a refrigerant leak is to replace the hose, seal or other part that is leaking. The other option is to add some type of A/C sealer product to the system to plug the leak. A/C sealer products contain various ingredients that can seal small pinholes in metal tubes, the evaporator or condenser, or cause hose seals and compressor shaft seals to swell to slow down a leak.

Such products can provide an easy and cheap fix for a small leak. But if overused, too much sealer in the system may gum up the compressor or orifice tube. Chemicals in sealer products can also plug up refrigerant recovery and recycling equipment.

COMPRESSOR OIL

Compressors require a certain amount of PAG oil to keep their innards lubricated and turning freely. The amount of oil used in a late-model A/C system isn’t much — only a few ounces in some cases — so it doesn’t take much of a leak to significantly raise the risk of compressor failure. What’s more, the type of PAG oil in the system must be the exact type specified by the vehicle manufacturer. PAG oil comes in various viscosities, and using the wrong one can also cause compressor failure.

A dose of compressor oil can be easily added to an A/C system when it is premixed with refrigerant. The problem with this approach is that the motorist has no way of knowing how much oil is in the system, and how much additional oil is needed. Too much compressor oil can also cause cooling problems by interfering with the flow of refrigerant through the condenser. It can also cause compressor failure if the compressor injects a big gulp of liquid and hydrolocks.

CONTAMINATION ISSUES

Another fact to keep in mind is that as refrigerant leaks out, air and moisture seep into the system. Air displaces refrigerant, making the system work harder and harder to provide cooling. Air contamination will reduce cooling performance and can also cause compressor noise. Moisture can freeze and block the orifice tube or expansion valve, which controls the flow of refrigerant through the evaporator, and it can react with the refrigerant to form acids and sludge that gum up the compressor and control valves.

The only way to get rid of air and moisture in an A/C system is to vacuum purge it with a special A/C vacuum pump. This is something else few do-it-yourselfers know anything about. If they’ve replaced a hose, a compressor or other A/C component themselves, the A/C system will be full of air and moisture. It won’t accept refrigerant very well when they attempt to recharge the system, and the A/C won’t cool well because it’s contaminated with air.

The correct way to complete an A/C repair, after a faulty component or leaky hose has been replaced, is to vacuum-purge the system for 30 minutes, and to make sure it holds vacuum before any refrigerant or oil are added. If the system holds vacuum, then it can be easily recharged with the specified amount of ­refrigerant and oil as needed.

If an A/C system has suffered a compressor failure, or it is found to be full of black gunk when a hose or other part is replaced, it should be flushed with an approved A/C cleaning chemical to remove the contaminants. If this is not done, any debris that remains in the system may cause the orifice tube to plug, or the compressor to fail.

Some types of condensers cannot be flushed ­because of their design (those with parallel flow tubes or extruded tubes with very small openings). The condenser acts like a trash collector and will catch any debris that comes out of the compressor. So if it can’t be flushed, it will have to be replaced. ­Following a compressor failure, both a new orifice tube and an in-line filter should be installed.

Larry Carley is an author for autocarepro news. You can email Larry at LCarley256@aol.com.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

The cause is microbial growth taking place due to moisture building up in the evaporator housing. You look for the usual suspects of a missing, pinched or restricted evap drain, but it’s not the case this time. Convention says use one of those products (such as AirSept’s Cooling Coil Coating) that clean the evaporator. Then, maybe add an afterblow module that will run the blower motor a few minutes after the key is turned off, to dry off the evaporator core to prevent the return of the nasty odor. You consider making that phone call to your favorite parts supplier when it occurs to you to check TSBs (Technical Service Bulletins). After all, you’ve performed the first two preliminary steps in any diagnostic process – you’ve verified the customer complaint and done a quick inspection. The next stop is your trusty ESI (Electronic Service Information) system.

Turns out there is a TSB for a musty smelling A/C. You’ve seen GM’s and other OEMs’ TSBs for cleaning evaporator cores and adding afterblow fan motor modules, but today is different. TSB 05-01-39-002A describes a musty odor from the HVAC being repaired with a reprogram of the HVAC control module by enabling its afterblow function with new software.

Welcome To The World Of Flashing!

Flashing (as it’s commonly called) or reprogramming EEPROMs (as you might more formally call it) has been around for years. In the late 80s and 90s, most of this work was performed with factory scan tools. Don’t own factory scan tool? Then you guess it may have to go back to the dealer. But you’re too short handed today to take the vehicle to the dealer yourself, so you may have to send your customer to the dealer. You hate doing that. The dealer might just lure your customer away permanently. This whole scenario with the 2003 Chevy may not be a problem at all, if you are willing to invest in something called a J2534 Universal Reprogrammer and get some training on how to use it. Intrigued? Read on!

Is There a Business Case?

Many of today’s service fixes, including the HVAC odor TSB just mentioned, are accomplished with software updates. Improvements to drivability, false DTCs, even making parts last longer, are often done with software. Years ago, modules were either changed via part number supersessions, or a pluggable EPROM was removed and replaced by the tech. This was not efficient for the OEMs to do under warranty, so they migrated toward modules that could be reprogrammed electronically. For years, new car dealers have enjoyed the ability to simply program new software into an existing module with a CD/DVD-ROM, or over the Internet using their factory scan tools. This gave them an advantage over the independent garage that had to work on several makes of vehicles and couldn’t afford all the factory scan tools required to keep modules up to date with the latest software. The EPA wants independent garages to keep cars running clean with the latest software, because that’s where most cars go when out of warranty.

While some OEMs only allow for mandatory powertrain module reflash ability, other OEMs have bumper to bumper J2534 compliant modules. Everything from engine and transmission, to HVAC and suspension systems, can be flashed on some vehicles (including, of course, the HVAC module in need of new software on the 2003 Trailblazer). Conservatively speaking, 1 out of 10 vehicles (’96 and newer) have an ECM/PCM software update available. Some studies say the number is as high as 7 out of 10. And some 2008 Chrysler vehicles have 40 processors, while BMW 7 series vehicles have over 100 processors. However you slice it, that’s a lot of potential business for anyone’s shop. It’s one job on a vehicle that does not require you to open your tool box, set the lift, or even require a service bay. No parts need to be stocked, so space and inventory tax are not factors.

What is the ROI (return on investment)? By seizing that one in 10 opportunity, a typical shop that works on three cars per day should gain back its investment in a few months, and a net profit within the first year. Other shops that are reluctant to send their customers to the dealer may want to sublet out the labor for flashing to a J2534 equipped shop. And the best part – no factory scan tools are required for J2534 flashing. Don’t get me wrong, I love factory scan tools and own several myself, but I simply can’t afford them all. So for those occasions when I need to flash a Ford or Toyota, I have a J2534 universal pass thru reprogrammer. I train aftermarket techs every week, averaging about 30 techs per class. When I ask for a show of hands of shops that own at least one factory scan tool, I usually get one or two hands. When I ask the same question about J2534 programming equipment, no more than one hand goes up. What does that mean to you? It means there is opportunity and very little competition in this area. What are you waiting for?

So What Exactly Is J2534?

J2534 is an SAE (Society of Automotive Engineers) standard for pass thru programming of computers on passenger cars and light trucks. J2534 was established for 2004 and later vehicles. The SAE document provides a framework for the interface between a tool and the vehicle. The OEM can decide the scope and method of module calibration downloads from the Internet or a CD/DVD-ROM, and the tool manufacturers can decide the interface between their tool and the PC (USB, RS232, wireless, etc.), which means there are going to be some variations on how each vehicle and each J2534 device on the market works out the flashing process (Figure 1).

For powertrain related modules, it is mandatory that OEM’s provide access to their software calibrations. It’s not mandatory for non emission related devices, so it will be hit and miss on whether you’ll be able to reflash an HVAC module or BCM on some models. GM is one of the OEMs that allows for bumper-to-bumper reflash, some even going back into the 90s, while Chrysler allows only for powertrain module reflashes. J2534 is also an evolving standard, as it changed to J2354-1 in April of 2004, and then again in March of 2006, when it became J2534-2 (to allow for more serial data bus protocols to be added). When shopping for a J2534 reflash tool, look for the latest standard, to ensure better coverage of vehicles.

Flashing, Configuring/Coding and Relearning

Not every one of those 1s and 0s inside a module’s head gets there the same way. In the case of J2534, there are some types or memory that aren’t completely erased and reprogrammed. Due to the small amount of data involved, there are “mini” programming procedures (that often involve only one block of memory data) which are completed without access to the Internet or a calibration disc. A scan tool is all you need for these cases. What are these procedures? European OEMs often use the term “coding,” while other OEMs may use the terms “configuring” or “module setup.” With the European car market, many aftermarket scan tools with the ability to code modules are coming along side the OEM factory scanners (as is the case concerning configuration procedures with many non-European OEMs’ modules).

An example of configuration would be the familiar adding of factory accessories. Let’s say you want to add a set of factory fog lights and your customer ’s vehicle utilizes the BCM in the process of controlling the fog lights. If you just bolt them on and plug into the factory wiring harness, the BCM still doesn’t know they are there, because the vehicle was built without fog lights. Using a scan tool (many times, only a factory scan tool will do the job), you connect and communicate with the BCM. Then select the appropriate RPO code and activate the option (Figure 2).

Relearning is similar to configuring and coding, in that it doesn’t require an Internet download or CD/DVD-ROM file. Examples would be idle learn, cam crank variation relearn, and fuel trim reset – procedures that most drivability techs have performed numerous times. Most aftermarket scan tools are capable of these relearning duties. Certain models, you may or may not be able to relearn, reset, or reconfigure with an aftermarket scan tool or the J2534 reflashing tool, so once in a while, a trip to the dealer is still going to be inevitable. The same is true for vehicles with certain immobilizer systems. An example would be Dodge Ram Cummins diesels – when programmed with a J2534 pass thru device, they will have to have their vehicle theft deterrent system (SKIM) programmed with a factory scan tool, unless a person at the local dealer decides to help you obtain the security code via the VIN. Everyone will agree that no matter how universal a tool is, there are always going to be exceptions where it doesn’t work. In most cases however, J2534 really works!

What Do I Need To Buy?

Since J2534 requires no factory scan tool, but rather a PC and an Internet connection or a file from a CD/DVD-ROM, you’re going to need the J2534 tool, a PC with a DVD-ROM, high speed Internet access, an e-mail account, and access to factory calibration software.

First, investigate the various J2534 programmers on the market (Figures 3, 4). You will want to see if they are compliant with the latest standard (J2534-2) and whether (or not) they are able to do off-board reprogramming. What’s off-board programming? It means a Pass thru tool has available a set of connectors that fit the most popular ECMs/PCMs, allowing for serial data, power, and grounds to be connected to the module while it’s outside of the vehicle.

To get modules as near as “plug and play ready” as possible, most parts stores that carry remanufactured ECMs/PCMs have a J2534 tool with an off-board programming cable set. There are some cases where off-board programming is beneficial, and some where it won’t work due to the manufacturer’s requirement to program the module in sequential order with other modules. Off-board programming cables don’t exist for non engine control modules, so the 2003 Trailblazer ’s HVAC head that was discussed earlier could not be flashed out of the vehicle. Take into consideration whether you might want to program engine control modules offboard. (Note: Not every J2534 tool has the option to buy off-board reprogramming cable sets.)

Once you’ve selected the J2534 tool, move your next focus to obtaining the right PC. A laptop PC is preferable to a desktop PC, due to the flexibility of where you can do flashing. Unless you purchase one of the more expensive ruggedized laptops (such as the Panasonic Toughbook®) you will need to admonish the techs in your shop to practice care with it. You can’t lay it on a filthy seat (the cooling fan will suck up dirt), you can’t pick it up by the screen (don’t ask me how I know this), and you can’t drop it.

Hardware requirements for the J2534 PC are not that demanding. A general rule of thumb is if it’s been built in the last two or three years, it’s probably good to go. Pick out the big volume OEM vehicle brands you see in your shop and visit their service website sections for J2534 hardware requirements before you start shopping for a PC. Both the OEMs’ PC requirements and J2534 tool makers’ requirements must be followed (Figure 5).

I also would recommend a “real” PC, not a mini net book or an Apple/Mac. I love my Mac and run a program on it that utilizes a virtual image operating system with Microsoft Windows XP and Windows Explorer, but I’ve never bothered to try to flash with it. I guess I’ve seen one too many Apple commercials where the PC guy and Mac guy are arguing about who’s better, and I don’t want that argument going on while I’m flashing a $500 control module. Just get a PC. If you have a PC that’s up to the task, make sure it gets reassigned to shop duty. Don’t try to dual purpose the laptop used by the bookkeeper as a flashing PC and office PC.

As important as the hardware is the software. However, as can be the case with PC based scan tool software, PC based flashing software from one vehicle manufacturer can have compatibility issues with that from another vehicle manufacturer. Operating system conflicts and PC terms like MS Java vs. Sun Micro Systems Java, cookies, pop up blockers, firewalls, spyware, antivirus programs, etc. are likely to be issues you’ll have to tackle. You may be thinking that these things are best understood by techs qualified to moonlight for the Geek Squad, so there’s no way you’re going to be able to do this flashing thing if this level of computer knowledge is required. But don’t stop reading – you CAN do it!

The details concerning what goes on inside your computer will typically be worked out when you perform the initial PC setup and installation of the various OEM software programs required to do flashing. It will kill a day or two of your time and will require persistence and good support from the J2534 tool supplier. It’s amazing what some J tool suppliers’ support teams can do these days. They can actually connect to your PC from offices several hundred (or thousand) miles away and see your frozen screen and control your mouse. That has been a lifesaver service for a computer challenged tech like me. In this day or two of setup, you’ll also be setting up a particular bay in your shop that can be utilized for flashing. Most OEMs require their calibrations for flashing to be downloaded from the Internet, so a high speed Internet connection is not just preferable, it’s an absolute. If you choose to go with a wireless connection, that will be fine, but make sure there’s nothing that will block the signal. I’ve heard of cases where there was a wireless router in the shop, but between the router and the bay used for flashing was a bay used for motor home repairs. A great big metal object like a Winnebago is not exactly conducive to the clear transmission of wireless Internet signals.

Next, you have to get the PC with the Internet connection linked to the vehicle via the J2534 pass through device. Most use a USB cable (Figure 6). Also, while it can be really handy to have a PC based scan tool communicating wirelessly from the DLC to the scan tool, I don’t advise doing that while flashing. Too many things can go wrong, and you really can’t afford to brain dead an expensive module.

In your flashing bay, you’ll need a battery charger that is kind to the electronic modules being flashed. If battery voltage gets below 12 volts while flashing, the module being flashed could be damaged, so you must keep system voltage levels up while programming. The average battery charger puts out voltage levels that can be too high, as well as far too much electrical noise. Snap-On and Midtronics produce battery chargers suitable for flashing. This rule for good clean uninterrupted power applies to the PC you use for flashing too. If you use a laptop, make sure it’s plugged in and not dependent on its own batteries. Disable screen savers too. You don’t want the PC taking a break in the middle of flashing.

Software Time

Now that you have the J2534 device, a suitable PC and a good Internet connection, and a way to keep the vehicle’s battery properly charged, let’s turn our focus to the software you’ll need to purchase. First off, you’ll install the software that either comes in the box with the J2534 device or is available for download from the J tool provider ’s website. Nothing super tricky here – just follow directions and have the tool provider ’s phone number handy.

Next are the files you’ll need to load in advance, prior to your first flashing task from the vehicle OEM. This isn’t the actual calibration file that will go into the vehicle’s module, but rather, important files required for accessing and managing that particular OEM’s calibrations once you do get a vehicle in for a reflash. I strongly recommend going to the handy clearing house website www.nastf.org, to visit each OEM’s site that you think you might be flashing in the future. If you only see a particular make of vehicle once in a blue moon, you might skip the information on them. But if you see a lot of Toyotas, Fords, Hondas, Chryslers and GMs in your bays, go to their websites, get registered with a login ID and password, then download any calibration management software that might be required (you’ll need to supply an e-mail address to do this too). The time consuming work of putting in your name, address and other business info, along with obtaining the calibration management software, will be done in advance. Preparation is the key to success in making each flashing job profitable.

Now, with the J2534 tool software in place, along with all the OEM-required file management software installed on your PC, you are ready to flash.

To Flash Or Not To Flash

So you’re ready to flash, but how do you know when to justify doing it? Obviously, if you are replacing an engine control related module, the new or remanufactured unit will require programming. Many new and remanufactured ECMs and PCMs are sold without engine start calibrations, so you really don’t have a choice here. If you or your customer opts for a salvage yard part, the same applies, even though it may start the engine. Fine details like engine RPO, VIN, tire size and axle ratio are contained in the end model calibrations inside the used engine controller ’s EEPROM. You’ll need to put the right stuff in it for your customer ’s vehicle.

Also, recall the smelly evaporator in the 2003 Trailblazer? Of course, that complaint was listed in a TSB indicating a calibration related solution. In a case like that (once again), its time to go flashing. But how do you obtain the actual calibration?

Most OEM websites are available with short term subscriptions. Typically, they range from very short terms (24-48 hours), monthly terms and yearly terms. Short terms typically cost $20-$30, while monthly are in the $100-300 range, and yearly, anywhere from $350 to $1500. Until recently, GM only allowed for yearly subscriptions, but they now sell a three-month subscription for $250 instead of a full year at $995. Tech 2 users who wish to flash and keep their Tech 2 scan tools up to date will have to subscribe for a year long term at $1395. The good news with the General is you can flash more than just engine controls, meaning our scenario with the HVAC controller flash to prevent return of the stinky evaporator can be accomplished with a three month subscription. If you get a lot of GM work in your shop, you’ll be getting you money’s worth after a few flashes.

Every manufacturer does things a little differently, so I’ll list a couple of examples.

Getting Chrysler Flash Ready

1. Subscribe to http://techauthority.com (Figure 7) and when inside the site click on “Flash.”
2. To download Chrysler’s file manager program, click where it says “Click Here,” then click on “Download Latest Application” and save to a location on your PC where you can find it easily. The download of a program called “DCX J2534 Update Manager” will take place first, then you will need to select “Run” for this program. This is the program which flashes Chryslers with the specific vehicle calibration software that you will obtain later (Figure 8). The first two steps are a one time only procedure and will not need to be redone on future jobs. Like many OEMs, Chrysler is one that only allows for the programming of engine controls with a J2534 tool. If you wish to program or reconfigure some other component, the factory scan tool will most likely be required.

The Actual Flash

1. Reopen Tech Authority and enter the part number you found on the ECM. Chrysler part numbers will always have eight digits with a two letter suffix. If there’s a calibration update, there will be a new two-letter suffix. Click on “Download” and click on “Agree” when a pop
   up window comes up next.
2. Close your Internet browser completely. The calibration is now on your PC, and you no longer need access to the Internet. Chrysler is somewhat unique compared to most other car makers in you don’t have to be online when the calibration is finally flashed into the vehicle.
3. Connect your J2534 pass through flasher tool to your PC and to the vehicle’s DLC.
4. Open the DCX 2534 Update Manager program. Click on “Select Pass-Thru” on the bottom left of the program and select the description of your J2534 tool and serial number (found on bottom of the J tool) to allow the DCX program to know which device you are using.
5. The rest of the procedure is to carefully follow the instructions that come up on your PC at the prompting of the DCX 2534 Update Manager program, as it performs its various procedures to flash the module in the vehicle (Figure 9).

Now you are pretty much done. Try to start the vehicle, and follow any other procedures recommended in the service manual, such as those related to theft deterrent or engine management relearns.

Getting Toyota Flash Ready

1. Toyota uses a DVD-ROM. Call 800-622-2033 to order from Toyota (Figure 10).
2. Install the program “Calibration Update Wizard” on your PC. A test screen will now come up. Read EVERYTHING – you must indicate that you have read it all before the DVD will allow you to advance. Most of “everything” is the usual advice and warnings we’ve already covered (Figure 11).

The Actual Flash

1. Check the vehicle to see if it already wears an “Authorized Modification Label.” If it does not, the ECU does not contain the latest calibration. Proceed with flash reprogramming.
2. Connect your J2534 flasher and open the tool’s program on your PC. Now click on “Analyze VIN/Current Software.” The flasher unit will basically run OBD II Mode 9 to obtain the VIN and calibration information.
3. Click on “Reprogram Controller.” Next, confirm the path for the software to move the calibration from the DVD to the vehicle via the J2534 device.
4. Carefully follow the Vehicle ECU Calibration Update Wizard instructions. If you fail to do so, the ECM may be damaged! You’ll be prompted to turn the key on and off at various times (Figures 12, 13).
5. Make sure you get a “Programming Successful” message when you’re done. Finally, install a dealer procured update label on the vehicle to let the next tech know the vehicle has the latest calibration.

These examples of Chrysler and Toyota show the differences and similarities between OEMs when it comes to using a universal pass thru J2534 flashing tool. After reading this, you’ll probably agree there are some come common threads when it comes to flashing:

1. You must be a technician who’s comfortable with computers.
2. You must be a technician who’s willing to carefully follow directions (oops, that leaves a few of us out)!
3. You must be a technician or shop owner willing to put in the time and monetary investments to carefully spec out, purchase and maintain a PC, J2534 tool, high speed Internet connection and most importantly, training for J2534 flashing.
4. Finally, you must be a technician or shop owner with a vision and sound business case for the growing future of module flashing.

Flashing is certainly not for everyone, and sometimes an article like this helps you determine that a particular service endeavor is not for you or your shop. If you’ve been reading this MACS Service Report and shaking your head no-no-no, we just saved you a chunk of money by convincing you to NOT purchase a J2534 flashing tool. On the other hand, if you are a visionary who wants to quit sending this fast growing segment of the service business to other shops and dealers, and you’re intrigued with the idea of making money selling parts (calibrations) that you never have to stock, then flashing may be for you. To help you even further, there will be two live training classes titled “Reflash/Reprogram/ Remobilize,” complete with flashing demonstrations, in Las Vegas next January at the MACS Convention. Hope to see you there!

Original article from MACS Service Reports, the official technical publication of the Mobile Air Conditioning Society Worldwide, Inc., P.O. Box 88, Lansdale, PA 19446. Click here to visit their website.

The latest SAE J2810 standards for refrigerant recovery machines, which replace the previous SAE J1732 standards, now require these machines to recover 95% of the refrigerant from an A/C system within 30 minutes.  Older recovery machines could take much longer, and sometimes left as much as 30% of the refrigerant charge in the system. Consequently, if the old refrigerant was dirty or contaminated, it would contaminate the new refrigerant when the A/C system was recharged.

The new J2810 standard does not require shops to replace existing refrigerant recovery machines. But if you are having refrigerant cross-contamination issues or comebacks because of refrigerant-related problems, the underlying cause might be your equipment. Replacing your old inefficient refrigerant recovery machine with a new one that meets the latest J2810 standards could be the answer to your dilemma.

A couple of years ago, SAE also released a new standard for recovery/recycling machines and recharging stations. The J2788 standard also requires 95% refrigerant recovery within 30 minutes, more accurate weighing of the refrigerant when recharging (plus or minus 0.5 oz.), an automatic purge cycle to vent air from refrigerant storage tanks, and a higher level of purity for recycled refrigerant.

Of course, meeting these specifications is not enough if you want the best equipment available. Many recovery/recycling/recharging machines now incorporate fully automatic controls that allow a technician to do something else once the unit has been connected to a vehicle and started. Automation combined with smart diagnostics that can detect faults (such as a leaky A/C system that won’t hold a vacuum) can boost shop productivity and eliminate mistakes that can cause comebacks.

Refrigerant Identifiers

Though R-12 is mostly history, cross-contamination issues persist in the field. People are recharging R-134a A/C systems with all kinds of concoctions. Consequently, if you don’t have a refrigerant identifier, you have no way of knowing what’s inside a vehicle’s A/C system. It could be good refrigerant or it could be junk.

Many recovery/recycling machines are now available with a built-in refrigerant identifier. Or, you can by a stand-alone identifier to use with existing equipment. Either way, it’s a must-have piece of equipment for anybody who services A/C systems today. Some identifiers give a “good” or “bad” indication based on the relative purity of the refrigerant (98% or higher is usually considered good). The more sophisticated identifiers display the percentages of various gases in the refrigerant, including air and hydrocarbons (flammable refrigerants). You can also use an identifier to check the quality and purity of refrigerant in a vehicle that is having cooling problems, to check your recovery and storage tanks, and to check the quality of the refrigerant you buy.

Something else you don’t want in your A/C service equipment is A/C sealer. Some of these products can gum up your equipment and cause all kinds of havoc. Using an identifier that can detect the bad chemicals and/or an in-line filter that stops the gunk before it can be pulled into your equipment is a wise investment that will reduce down time and maintenance costs.

Leak Detection

Some type of leak detection capability is also essential for finding refrigerant leaks. Fluorescent dye that glows yellow or green when illuminated with ultraviolet (UV) light is certainly useful for finding small leaks. But it takes time to find really small leaks using UV light, and may be no help whatsoever when searching for evaporator leaks. So you also need a good electronic leak detector that can sniff out leaks in places where dye can’t be seen or takes too long to find the leak.

If you are buying an electronic leak detector, make sure it meets the latest SAE J2791 standards, which require much greater sensitivity and accuracy than the former SAE J1627 standard. The latest detectors can find leaks as small as 4 grams per year, which is more than three times better than the previous generation of leak detectors. Additional settings allow the sensitivity to be adjusted to detect leaks of 7 or 14 grams per year. The new standard also requires the detectors to not trigger false alarms for extremely small leaks (2 grams a year or less) that are insignificant.

Diagnosis

Nothing beats a good high and low pressure gauge set for diagnosing A/C problems — if a technician knows how to use them. Like any skill, it takes training and experience to learn how to use a gauge set. An easier alternative for many is to buy equipment that takes much of the guess-work out of diagnosing common problems in the refrigeration circuit. These diagnostic units are not cheap, but they essentially do the job of an experienced A/C technician with the press of a button. These units typically look at the high and low side pressure readings to detect problems that affect cooling performance. The units are not fool-proof, but they do provide a relatively quick and easy way to verify A/C system performance — and they don’t require the skills of a master technician to operate.

Another tool that has become a necessity for troubleshooting late-model automatic climate control systems is a scan tool. A scan tool can access fault codes, check sensor inputs and run various self-diagnostic tests to test the operation of the A/C system. On many vehicles, a scan tool is also required for various A/C system reset and relearn procedures. So if you don’t have a scan tool that can access the body computer or climate control module, you’ll be sending a lot of your work back to the new car dealer for diagnosis and repairs.

A good digital volt ohm meter (DVOM) is also essential for troubleshooting electrical circuits, relays and other electronic components in the A/C system.

Flushing Equipment

Moisture contamination causes acids and sludge to form inside A/C systems. If not removed, the sludge may gum up the orifice valve or expansion valve, and/or cause the compressor to fail. Condensers can also be contaminated with metallic debris if a compressor fails.

Though many condensers cannot be flushed to remove sludge or contaminants, some can. The same goes for hoses and lines. A good flushing machine and the right kind of solvent can give you the flexibility to do this kind of work if the situation warrants it.

Line Repair Tools

Having the ability to fabricate and repair damaged or leaking A/C lines and hoses is certainly a plus for any shop. To do this kind of work, you need a kit for forming end fittings on lines to accept compression fittings and crimping tools for installing various types of hose fittings.

New Equipment Requirements Down the Road?

The debate over the future of R-134a still remains uncertain. In Europe, the automakers are moving toward R-744 (carbon dioxide) as the next generation refrigerant. But R-744 requires extremely high operating pressures and is totally incompatible with today’s A/C systems and service equipment.

HFO-1234yf, which is DuPont’s latest refrigerant, is being touted as the best alternative to R-134a. It has very similar operating characteristics (same temperature and pressure curves as R-134a), pressures and cooling performance; there are no materials compatibility issues; and it appears to have lower flammability than R-152a (another potential successor to R-134a). The main attraction with HFO-1234yf is its low Global Warming Potential rating — only 4 versus 1,200 for R-134a. Politics and economics will ultimately decide whether automakers replace R-134a with something else or continue using the same refrigerant they have used since 1995. Any such change is still years away, so don’t let that influence your A/C service equipment buying decisions today.

Larry Carley is an author for autocarepro news. You can email Larry at LCarley256@aol.com.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

By Ed Sunkin.

Recent news has been the industry’s move toward a new refrigerant — HFO-1234yf — for mobile air conditioning systems. The move is expected to begin in European vehicles and eventually become common in domestic vehicles.  (See Directions, March 2010 issue.)

While we discussed the reasons why the change was being implemented, what the product will accomplish, who is part of the new refrigerant movement and where and when it will occur, this month, we’ll take a look at how all that can effect your shop, technicians and bottom line.

What It Means for Shops and Techs

In a presentation with MACS and DuPont officials in January in France, it was explained that shops should expect some potential service differences with HFO-1234yf.

The most obvious is the need for service shops to purchase and operate new recovery, recycling and system recharging equipment. Shops will not be able to use the same R-134a refrigerant equipment when servicing the new HFO-1234yf systems.

Equipment manufacturers we spoke to said they are currently in development of new equipment to handle the HFO-1234yf systems and adhere to updated SAE guidelines for such equipment.

It also was noted that refrigerant identifiers and updated leak detection equipment would be necessary for shops to service these systems.

Safety Issues

According to the new refrigerant’s developers, there are chemical differences between HFO-1234yf and the current R-134a system.

For example, HFO-1234yf is mildly flammable, so technicians and shop staff would need training to understand the precautions that need to be followed when used with other flammables (i.e. gasoline, oil).

Also, since the new refrigerant is heavier than air, care must be taken in the shop in low-lying areas (such as workshop/oil drain pits, shafts or cellar exits), which may cause released refrigerant to pool. Service technicians should not smoke or have any open flame present while working on these refrigerant systems or in the low-lying areas where HFO-1234yf could accumulate.

One of the proposals is to require work areas to be adequately ventilated and fans available if needed.

Be Mindful of Mix-Ups

Cross contamination is also expected to be an issue in the early stages of HFO-1234yf use in vehicles, as DIYers may charge non-approved refrigerants into these A/C systems.

The outcome of cross-contamination could be system failure or system misdiagnoses if the technician isn’t informed of the mixed refrigerants in a vehicle’s A/C system.

Product manufacturers also will take precautions to reduce cross-contamination at the shop. Currently, packaging for R-134a refrigerant is in light blue, 30-lb. returnable containers.

Packaging color for HFO-1234yf containers (also offered in 30-lb. returnable containers) will be white with red band around it.

And, don’t expect to perform any R-134a to HFO-1234yf retrofits. While R-12 to R-134a
retrofit jobs at service shops were a “hot topic” in the mid-1990s, the EPA said R-134a product would remain available to service existing systems.

That concept may work better this time around. While retrofits in the 1990s did provide shops additional revenue and service opportunities, many customers felt the new systems didn’t cool their vehicle cabins efficiently. This is because those vehicles were designed to use the (better cooling) R-12 systems, rather than a less-efficient R-134a system.

And, let’s not forget the “mystery refrigerant” fiasco of the late ’90s, as DIYers never really knew for certain what was in that container of bootlegged R-12 that they used to charge their system. Incidents like that were tough on shop owners when they found out their recovery equipment became contaminated or they had to dispose of a flammable “cocktail” of refrigerant recovered later from that vehicle’s system.

Since manufacturers will continue to produce R-134a with no interruptions until these systems slowly phase themselves out, the issues of bootlegged and unknown refrigerants should diminish.

SAE and the EPA also explained that HFO-1234yf systems will also use specific fittings that are different from R-134a units in an effort to minimize accidental cross-contamination.

And, the EPA also stressed that HFO-1234yf refrigerant system components should not be replaced with ones removed from a system that uses another type of refrigerant (R-134a) or from a salvaged vehicle.

Charging Costs

Finally, customer feedback is going to be something you will need to deal with. According to manufacturers, the new refrigerant will cost more to produce. While no pricing has been introduced until the market dictates mass production of the refrigerant, it is estimated by some that HFO-1234yf could cost anywhere from $35-$60 a pound.

So, you can pretty much expect some customers who have their HF0-1234yf systems serviced down the road will give you an earful when they get a service repair estimate. When dealing with such customers, just remember to “keep your cool.”

Ed Sunkin is an author for autocarepro news. You can email Ed at esunkin@babcox.com.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

Due to its high cost, few automakers adopted GDI to be used in mass-market cars. GDI sort of disappeared from the automotive scene until its comeback in late ’90s models of Mitsubishi, Toyota, Nissan and Renault. Through the 2000s, many automakers such as Ford, Volkswagen, GM and BMW began trending toward the direct injection engine due to its significant design advantages.

What about today’s GDI engine? Soup it up with a flex fuel capacity, super high output (SHO), 3.5L twin turbocharged EcoBoost™ V6 engine and you’ve got Ford’s 2009 Taurus GDI model.

GDI vs indirect injection

Today, most fuel-injected engines use indirect fuel injection that premixes the fuel and air in the intake manifold. With direct injection, however, the air still flows into the cylinder from the intake manifold but the fuel is sprayed into the cylinder separately.

GDI is known to be a more expensive system, so what is the value over indirect injection? Take a look at these advantages.

• Advantages over indirect injection:
  • Better MPG
  • Leaner fuel mixtures
  • High power output
  • Accurately controlled emissions levels
  • More aggressive ignition timing curves
  • Precise control over amount of fuel and injection timings
  • No throttling losses in engines without a throttle plate

The disadvantages for the GDI system are few but can be catastrophic if they’re not closely monitored.

• Disadvantages:
  • Dramatic efficiency losses due to deposits on the piston surface
  • More deposits on the intake ports and valves
  • Low mileage misfire codes

These disadvantages present opportunity for BG. We’ve found that regular maintenance using BG products can keep these problems to a minimum.

The future for GDI

For model year 2009, GM is offering direct injected engines in 10 models in North America, 18 worldwide. For the 2010 model year, GM will have direct injected engines in 38 vehicle models worldwide, with 18 models in North America alone. In the next five years, Ford plans to have at least 500,000 cars a year powered by GTDI engines – that is, Gasoline-turbocharged-direct-injection. CSM Worldwide, a global automotive forecasting and advisory firm, estimates GDI technology to be in 21 percent of new gasoline engines in European-built cars by 2013. CSM also projects sales of vehicles using direct-injection gas engines will jump to 5.1 million by 2014 from 585,000 in 2009.

It’s safe to say GDI engines will be around for a while… and BG will be there to help keep them clean. In fact, we’ve taken a proactive approach to solving GDI deposit problems by purchasing our own test vehicle: a 2010 3.5L Ford Taurus SHO with an EcoBoost™ engine.

Follow BG’s test vehicle and learn more about GDI technology at BGFuelTest.com.

Fuel System Voltage Drop Test

1. Address the negative side of the circuit first, then the positive side.

2. Connect one digital voltmeter test lead to the negative battery terminal and the other to the negative terminal at the fuel pump.

3. The fuel pump circuit must be energized to properly test. Energize the fuel pump relay and power the fuel pump circuit (see NOTE below).

4. If the negative circuit is in good condition, the voltage drop measured should be 0.5v DC or less. Larger voltage drop readings indicate a problem. Damaged or corroded vehicle wiring or harness connectors are likely sources of the problem.

5. Repeat the voltage drop test on the positive side of the circuit. Connect one digital voltmeter probe to the positive terminal on the battery and the other to the positive fuel pump terminal.

6. Energize the fuel pump relay and power the fuel pump circuit (see NOTE below).

7. As with the ground circuit, voltage drop readings larger than 0.5v DC indicate system wiring or connector issues.

NOTE: The majority of fuel pumps run for only a few seconds once the relay is energized (only long enough to prime the system) until an RPM signal is generated.

For information on products offered by Airtex and to view additional Tech Tips, visit www.airtexproducts.com.

Content provided courtesy of autocarepro: news; providing automotive shop owners, managers and technicians with a website and e-newsletter filled with products, tech tips and automotive news needed to be successful in the marketplace.

By Barry Gersten.

Test Exhaust Gases for

• Driveability Diagnosis
• Repair Verification
• Confirm Manufacturer’s Specifications

Which gasses should be measured and what would it reveal
HC – Raw, unburned fuel. Under 100 ppm is good.
O2 – Oxygen. Less is better, more indicates problems with A/F Ratio, intake leaks, misfires. Look for 1% or less.
CO – Fuel that has not been completely burned. Indicates fuel mixture, rich/lean. Usually, under 0.5% is good.
CO2 – Audit gas, how complete is combustion. More is better. Look for about 15% in a good running engine.
NOx – Oxides of nitrogen. Too much implies faulty egr, high engine temp, serious carbon build-up, over-advanced ignition timing or a failing catalytic converter. Expect zero NOx at idle, and less than 500 ppm under load.

Measurement of exhaust gasses will improve customer relations

• Customers appreciate the higher level of technology offered at a shop using Exhaust Gas Analysis.
• The nature of the driveability repair market makes the use of a 5 gas analyzer a very good idea.
• Very often diagnosis is made without raising the hood… very impressive.

The engineers in Emission Attainment areas know what they are doing.
For Driveability Testing Commit to Measuring all 5 Gasses. They ALL matter.

Quick Solutions to Driveability Concerns
We see it happen all the time. A driver complains about poor gas mileage. No codes are set. Is there a problem that can be fixed? Or, is the driver just hoping for a solution we can’t provide? Extensive testing of the engine, fuel system and ignition system may reveal that fuel injector service, a tune-up, or some engine repair is needed. However, it is much faster and easier and more professional to simply probe the tailpipe exhaust gas and know how to proceed without even raising the hood.

Ignition system problems resulting in a misfire always mean that a charge of air and fuel leave the cylinder unchanged. The Gas Analyzer will show high HC (unburned fuel) along with high O2 (air). When the other gasses are normal just find the cause of the ignition failure and don’t waste time looking for fuel problems.

Another example of “driver complains about poor gas mileage”. No codes are set. Same questions for us – Is there a problem we can fix? How do we start to figure out how to help? Extensive testing of the engine, fuel system and ignition system are not necessary. Simply probe the tailpipe exhaust gas and know for sure how to proceed without even raising the hood. In this case all the gasses are normal except CO, which is high at 3.5%. Normal CO is usually less than 0.5%. We can now proceed to solve a “Too much fuel” problem.

Other examples are very similar. Reading the exhaust gasses makes you the smartest technician in the neighborhood. The Best Driveability Pros make regular use of an exhaust gas analyzer.

For health reasons large cities with the potential for high levels of smog usually require automotive exhaust gas testing to minimize pollutants which contribute to ground level ozone. NOx is formed when engine combustion temperature gets excessively hot. In the presence of sunlight NOx will change to ground level ozone. Ozone is very reactive and even in very small amounts can cause eye and lung irritation

Informed Shopping…

Ask the Right Questions – What concerns are important enough to influence my decision?

1. Is the instrument really portable, will it fit comfortably in one hand
2. Is it necessary to connect the instrument to the vehicle battery or is it self-powered
3. How will exhaust gasses be removed from the vehicle interior
4. Will it be necessary to use Calibration Gas to calibrate the analyzer
5. Can the instrument show air/fuel ratio and Lambda
6. Does the instrument have “Memory” to save test data for comparison and analysis
7. Is the instrument able to read Propane and CNG for my fleet accounts using alternative fuels
8. Can the pump be turned off while the bench stays on so the analyzer won’t need a warm-up period each time it is used
9. Who makes the BENCH? The bench is the central measuring part of any automotive gas analyzer. It is best when one company is responsible for manufacture of the entire instrument
10. What about cost of ownership as well as initial cost. With fragile instruments expect a recommended “Maintenance Agreement”
11. Can the instrument be used for Diesel Exhaust Testing – New rules involving Diesel Exhaust are almost here
12. Are all 5 gasses really measured or is it really a 4 gas Calculating a fifth gas
13. Is the instrument Computer Compatible to Graph Gasses
14. What about Training and Reference Materials
15. Is Helpline Support included or charged for, or not even available
16. When the O2 Sensor wears out (normal maintenance) will the instrument still function showing the other gasses or will it shut down pending Sensor replacement

Automotive Scope Applications. Call them at 888/717-1333 or check out their website at www.labscopes.com.