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By walrathrod2013
I’m trying to verify if a window regulator for a 1981 Chevy pick up will work on a 1973 Chevy pick up. Both with manual windows.
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By Counterman
Engine misfires are among the most common issues that a technician must diagnose. However, the biggest problem – from a diagnostic standpoint – is that it’s almost an automatic reaction to blame misfires on the ignition system. Understanding why this is a problem, and the reason it happens, can help you differentiate between ignition-related and non-ignition-related misfires.
There are a couple deep-seated reasons for the blame. To begin with, years ago, before fuel injection and distributorless ignition, the majority of all noticeable misfires were caused by an ignition problem – either a bad spark plug or plug wire. Note that I said noticeable misfires. On today’s vehicles, ignition problems indeed are a common cause of engine misfires … but also a common misdiagnosis. This is where it starts to get interesting.
Carburetors, distributors and plug wires got us through the first 80-plus years of the automobile, and did a great job at it. But the bottom line is that they were simply inefficient fuel and ignition systems. Compared to today’s vehicles, they ran terrible! Once you had a few miles on them, they idled rough, maybe had to warm up a little longer to avoid a stumble, and most cars had their own little idiosyncrasies for starting.
This was the type of performance we were used to, so nothing registered to us as a misfire until it was a “dead” miss. This is a term we as technicians use to refer to a misfire that renders a cylinder completely ineffective, or completely “dead.” These types of misfires shake the entire vehicle to the point where even the most absent-minded of vehicle owners knows something is wrong.
It Was Easy Once
Back in the day, spark plugs had relatively short service intervals – around 10,000 miles – and plug wires were wide-open to abuse and wear. So, not only were they the frequent cause of misfires, but it wasn’t uncommon to open the hood and see a spark jumping from a plug wire to ground, or between wires. This made it easy to diagnose, and if there was no visual cue such as this, a common trick was to use insulated spark plug wire pliers and pull off one wire at a time to see if it made a difference. If you got no change, you found the suspect cylinder. If you got the daylights knocked out of you, you needed a new set of insulated pliers!
This was a sloppy yet effective diagnosis, but by no means an insult; I’ve done it a “million” times. Now, let me get back to the diagnostic problems of a misfire. For complete and correct combustion to occur, you must have the proper amount of air, fuel and spark; you must have the correct amount of compression; and the ignition timing must be correct. So, the possible causes of incomplete combustion could be too much or too little air; too much or too little fuel; lack of or not a strong enough spark; spark at the wrong time; or a mechanical problem that causes insufficient compression.
On old cars, incomplete combustion was common (one reason emissions were so bad), but there was no computer, no electronics to tell us, and as I mentioned, we were used to engines that ran a little rough and didn’t have the best drivability. On today’s vehicles, complete combustion is critical for emissions and fuel economy. This is why the engine control module (ECM) continuously monitors for complete combustion, and while there’s a lot to that, we’ll just focus on the misfire monitor.
The operation of the misfire monitor is primarily based on crankshaft pulses. The ECM continuously monitors crankshaft speed via the crankshaft sensor, and if it sees even the slightest deviation, its logic deduces that some form of incomplete combustion (i.e., a misfire) has occurred. Since any type of incomplete combustion will cause an increase in emissions, a diagnostic trouble code (DTC) is stored, and the “Check Engine” light is illuminated.
While the driver of the vehicle might not have noticed anything wrong, the ECM did, and now there’s an annoying light glaring at the driver, enticing them to seek service. As a technician, when we pull the DTCs on a vehicle that seems to run fine, it’s not even a slight surprise to see misfire codes, which are always P0300 for random misfire, or P0301 and up (the last number indicating the cylinder from which the misfire occurred).
When You Assume …
With all of that said, now let’s focus on the diagnostic problem of assuming that a misfire is caused by ignition. Problems such as the slightest pinhole vacuum leak or the slightest loss of fuel delivery from an injector will be detected by the PCM, storing a misfire trouble code. If we allow ourselves to automatically blame it on ignition, a percentage of the time we will be wrong. However, since we know that ignition problems still are common, there are certain signs we look for and certain things we can do to determine if the problem is ignition-related.
To begin with, one telltale sign of an ignition misfire is the flashing “Check Engine” light. As part of emission control, all ECMs will store trouble codes when a misfire is detected. But, when the ECM determines there’s imminent danger of damage to the catalyst, it flashes the “Check Engine” light to get the immediate attention of the driver. This occurs when it picks up a “dead” misfire, with the logic that quite possibly there is excessive unburned fuel coming out of the dead cylinder, which will damage the catalyst.
These “dead” misfires again can be felt by the driver, so a shaking vehicle and a flashing “Check Engine” light go hand-in-hand. While not always, this is usually an ignition problem, and quite often the engine will idle smooth, but under acceleration begin to misfire and flash the light. Most misfire monitors are accurate with the reported cylinder, and a common practice for diagnosis is to swap the coil and plug from the suspect cylinder with those from another. More often than not, the misfire will move, and while it feels the same, the ECM will instantly report the misfire from the other cylinder.
Rolling back the clock again, even in the age of the carburetor, technicians knew that misfires could be caused by multiple factors aside from ignition, and if a car had a misfire that wasn’t blatantly obvious, we relied on an oscilloscope to be able to “look” at the operation of the ignition system on a screen, which allowed us to compare the efficiency of all cylinders and deduce whether the problem was ignition-related, or caused by another factor.
These tools and techniques still are relevant today, but there are more special-tool requirements for more vehicles, as opposed to one set of test leads that you could hook up to any make or model. As technicians, we always take into account all of the factors that can cause a misfire, so as not to misdiagnose it. However, we may not always have the required equipment to view ignition waveforms, so we continue our inspection with more signs that can indicate an ignition-related misfire.
Spark Plugs and Critters
Naturally, worn spark plugs can cause a misfire. If you know the mileage on them, it can help you decide whether it’s time for replacement. Once they’re removed, excessively worn electrodes are a good clue.
It’s always important to look for wiring damage. Coil wiring can be inviting for rodents, so a close inspection always is a good idea. Carbon tracking is another tell-tale sign of an ignition misfire. The high-voltage spark produced in the coil finds its path to ground by jumping across the gap of the spark plug. Electricity always takes the easiest path to ground, and if it finds an easier way than the spark plug gap, it’ll go there.
Spark plug wire or coil boots are designed to insulate the high voltage, but problems can cause the spark to travel under the boot and ground to the base of the spark plug. Carbon is a byproduct of an electrical spark, and a high-voltage spark traveling between the wire boot and plug will leave its “footprint” via a carbon track.
Carbon tracking also can be visible inside a distributor cap, and where you find it, you can be sure of an ignition misfire. A final visual indicator of an ignition misfire can be oil in the spark plug wells. Many of today’s cars are designed with spark plugs in the center of the combustion chamber. It’s common in these designs for the well seals to leak, and oil can work its way up underneath the coil boot and cause a misfire.
During any type of diagnosis, we always use sight, sound and smell as our most important tools. Even if you can’t see it, you get used to the sound of a jumping spark, and this can be an indicator of an ignition misfire. You also might smell excessive fuel at the tailpipe. There are other indicators with scan-tool data that can give you a clue as to whether you have an ignition misfire, but you have to be careful.
If you have an ignition misfire and excessive fuel is being introduced into the exhaust, the engine-management system will recognize this as well and make adjustments to fuel delivery, which can alter engine data and the smell from the exhaust.
As you can see, this is a really deep hole, and the bottom line is engine misfires can be difficult to diagnose at times due to the sensitivity of modern engine-management systems. However, a thorough inspection and careful mindset will allow you to head off an ignition misfire before getting too deep into additional diagnostics.
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By chevyguy
So I had some problems with slippage during some of the hot days. Bought this 2014 chevy equinox AWD used with about 90k on it and I guess the tranny was never serviced. Drained and refilled the fluid in the transmission, which was only about 4 quarts or so (need to flush to get it all) and it was black. Did it again in a week or so to mix in some good fluid. Car ran alright but instead of a slippage, it started to develop a hard shift. Next day, started to drive it and it would all of a sudden rev out like its in neutral. Coasted the car to the side of the road and moved the shifter, but would not engage into drive or reverse. i shut the car off and restarted and then it would go into drive (electronic control) but after a few feet it would pop back into a neutral state with the shift indicator in drive.
No codes, no lights.
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By Counterman
Performance Ride Technology (PRT) will be exhibiting its full line of shocks, struts and complete strut assemblies at AAPEX 2022.
The display will include a new product line and various first-to-market applications, according to the company. Some of the product launches apply to brand-new vehicles such as the 2022 Honda CR-V and 2022 Jeep Cherokee.
The new product line, PRT air shocks, is an OEM-quality replacement for air-suspension systems, “providing the luxury and comfort of a smooth ride at an affordable price,” the company said. The PRT air shocks and packaging also will be featured in the AAPEX Showcase.
In addition, the company will be presenting an extensive portfolio of heavy-duty applications. The PRT heavy-duty program offers coverage of more than 4,600 OEM references with 100% gas-charged shocks for trucks, trailers, buses, commercial vehicles, cement mixers, motorhomes and more.
PRT will be exhibiting in Booth A2261 at AAPEX, which is scheduled for Nov. 1-3 in Las Vegas.
PRT is a brand of ADD USA group, one of the largest manufacturers of shocks, struts and complete strut assemblies in the world.
“We are very excited to present the PRT air shocks and all these new applications to our clients,” said Bruno Bello, director of global category and marketing at PRT. “As an OEM supplier, we are continually investing in research and development of new products and technology, which allows us to bring the latest innovations to our clients at AAPEX.”
As a global presence brand, PRT also will exhibiting at Automechanika Dubai 2022.
For more information, call 770-238-1611 or visit
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By Counterman
When I hear the term diesel, the first thing I always picture in my mind is an 18-wheeler. Then my thoughts drift to gleaming chrome stacks, tons of load-hauling torque and the sounds of a semi-truck. The next thing you know I’m kicking back to watch the greatest trucking movie of all time, “Convoy,” for what’s probably the 10th time.
I’m sure it’s generational, because growing up, diesel engines were only popular in heavy-duty trucks. Whether the big rigs defined the persona of a diesel engine or vise-versa I’m not sure, but to me the term “diesel” always has been synonymous with power and strength. So, what’s a light diesel? It seems like a contradiction of terms to me.
A light diesel in the simplest way of thinking is anything diesel-powered that resides in someone’s driveway as daily transportation, including everything from cars to pickup trucks. The true definition gets a little muddy at a certain point because the federal standards have different weight cut-offs for their light-truck classifications.
Using these standards, most full-size pickup trucks are all considered light-duty, even when they’re equipped with torque-monster diesel engines. But, if it’s a dually crew-cab 1-ton, it just might make it into the heavy-duty classification. Either way, it really doesn’t matter. Parts are parts, and if they’re driving it and fixing it, they’ll look to you – the counter professional – for what they need.
Diesel Drill-Down
As with any subject, knowledge gives you the power to sell, so I’ll start with what’s different about a diesel. There are three things that diesels are typically known for: fuel economy; lots of power; and long life.
Why does a diesel engine get better fuel economy? Diesel fuel has a higher energy density than gasoline. This means that it takes less of it to produce the same amount of power resulting from combustion. Diesel engines also have much higher compression ratios than gasoline because the fuel is ignited by the heat of compression, and higher compression ratios in general lead to increased combustion efficiency.
Why do they produce more power? Although modern diesel engines have the ability to produce incredibly high horsepower numbers, the “power” normally associated with a diesel engine is actually high torque. Torque is low rpm power for pulling, and horsepower is the high rpm power for acceleration. Diesel trucks are designed for pulling, which is why torque is so important.
When the air/fuel mixture burns in a gasoline engine, it burns quickly, and the force of the expanding gasses drives the piston down in the cylinder. This creates power. However, once the air/fuel mixture has burned and the piston is traveling downward, the further down it goes, the less force is exerted upon it.
Diesel fuel burns slowly. When the combustion process begins, the force of the expanding gasses pushes the piston downwards, but the air/fuel mixture continues to burn as the piston travels downward, exerting continuous force on the piston until it nears the bottom of the stroke. This continuous force on the piston is why diesel engines produce so much torque. Modern electronic control of diesel-fuel systems has allowed them to precisely control fuel-injection time to maximize this effect.
Do they really last longer? As long as they’re properly maintained, yes – and here’s why. Gasoline is a harsh solvent with no lubricity. It wreaks havoc on everything it comes into contact with, including the inside of the cylinders in an engine. Diesel fuel, on the other hand, has a high level of lubricity, drastically reducing cylinder wear.
Another reason for increased longevity also has to do with the slower speed in which the diesel fuel burns. The combustion of gasoline is a violent process that applies incredible stresses on the rotating assembly, whereas the diesel-fuel combustion process is less violent, applying a steady, continuous downward force on the piston.
Then there’s temperature. Diesel fuel ignites at a lower temperature than gasoline, so combustion temperatures, as well as exhaust temperatures, are lower. And finally, there’s construction. Because of the higher compression ratios, diesel engines are built stronger and sturdier from the block and heads to the rotating assembly, often with increased oil capacity and improved oiling systems.
Sales Opportunities
In recent years, there’s been turmoil and scandal related to diesel-powered vehicles, and now there’s plenty of speculation that the end of the diesel isn’t too far off. But diesel owners aren’t ready to give up – meaning parts opportunities abound. With fewer diesel vehicles available, there will be a stronger push to keep the current ones on the road.
Some areas of repair – such as timing belts, water pumps and hoses – ultimately don’t differ from a gasoline vehicle. However, an area where you can capitalize is maintenance. Diesel engines can last a long time, and that longer service life extends the opportunity to sell maintenance items.
Fuel Treatment
An immediate area to take advantage of is fuel treatment. The fuel system is the heart of a diesel. Fuel quantity controls engine speed. There’s no ignition system, and there’s no air-volume control or throttle plates like those on a gasoline vehicle. (In case a customer decides to call you out, there are some diesels with throttle plates, but they don’t have anything to do with controlling engine speed – they only smooth out engine shutdown and increase exhaust-gas recirculation.)
Diesels have complex and expensive injection pumps and injectors. Not only does diesel fuel extend cylinder life with its lubricity, but it also preserves the life of the fuel system itself.
The problem is that in order to reduce air pollution, ultra-low-sulfur diesel fuel was introduced in 2006. By losing the sulfur, diesel fuel also lost the majority of its lubricity. This can be, will be and has been a big problem. Diesel-fuel treatments add back this lubricity, and while they may seem expensive to a customer, a small bottle treats many gallons, and if it’s properly measured, it ultimately only results in a minor fuel-cost increase.
Cold-weather performance is another problem. Diesel fuel has always had a tendency to gel in extremely cold temperatures, and the loss of sulfur has made it worse. Diesel-fuel additives will combat this problem as well. Additives also battle cylinder deposits, and on a diesel engine these deposits soak up diesel fuel and effect fuel economy. Fuel additives should be recommended for continuous use.
Filters
Next on the easy-sell list is filters. Air filters fall under standard replacement guidelines that you’re used to, but fuel filters are an area to concentrate on. Contaminants can be very damaging to diesel-fuel pumps and injectors, and water accumulation in diesel fuel is a common problem. Diesel fuel often is stored for longer periods of time than gasoline, and the water accumulation is a result of condensation from temperature change.
For this reason, almost every piece of heavy equipment has an individual water separator, and even many small diesel cars have water-drain valves in the bottom of their fuel filters. Generally, water accumulation isn’t a problem at larger-volume gas stations, but there’s no way of knowing for sure, so it’s better to err on the side of caution. Diesel-fuel filters should be replaced at least once a year.
Performance
Performance upgrades are common among diesel enthusiasts – especially intake and exhaust systems – but it can be a difficult market to get into since there are so many different options and applications. The best opportunities lie with accessories and upgrades that fit all models, such as gauges, lighting and interior accessories.
Oil Changes
When diesel fuel burns, it leaves behind black soot. This soot finds its way past the piston rings into the crankcase and turns the engine oil black. Even when changing the oil, there’s almost always enough residual oil in the pan and throughout the engine that the new oil is black almost immediately. The soot doesn’t harm the properties and performance of the oil, but think of it like any dirt particles: If there’s too much of it, the oil performance will degrade.
It’s easy to see oil condition on the dipstick of a gasoline engine, but on a diesel there’s no way of telling. It’s critical for vehicle owners to document oil-change mileage so they don’t go over. It’s best to follow manufacturer recommendations for oil type, and it’s a good idea to recommend a high-quality oil filter. While diesel-powered cars typically have standard oil capacities, many pickup trucks have much higher capacities – sometimes 10 quarts or more. If your customer isn’t sure, take the extra step of looking it up so they don’t get home and end up short.
Cleanup
If your customer is doing an oil change, this is the perfect time to sell latex gloves, disposable rags and other cleaning supplies. Diesel oil will stain your hands for an entire day, and it doesn’t help the look of your garage floor either. We always should wear gloves to protect our skin during an oil change, but admittedly I don’t always do that on a gasoline vehicle. Diesel is a different story.
Diesel Exhaust Fluid
For the 2010 model year, the EPA mandated that diesel engines reduce the production of nitrogen oxides (NOx), which is linked to the formation of acid rain and smog. Diesel exhaust fluid (DEF) is what allowed manufacturers to meet these requirements. DEF is a solution of urea and deionized water that’s injected into the exhaust system before the catalytic converter. The chemical reaction forms ammonia, which then works in conjunction with the catalyst to convert NOx into nitrogen and water.
It’s ultimately a simple solution, but diesel owners need to keep the DEF reservoirs full. If the DEF runs out, the vehicle will not start. If they’re running, they won’t quit, but often go into a low-power mode.
Block Heaters
Historically, diesel engines were known for difficult cold-weather starting, since the heat of compression ignites the fuel. Modern combustion-chamber design and technology have greatly improved this problem, but in the far northern regions of the United States and in Canada, diesel owners often don’t have a choice but to install a block heater. Even in areas where starting isn’t a problem, block heaters are popular in the winter since diesel engines take a long time to warm up.
There are two different types of heaters. Most factory-style heaters are designed to fit directly into the engine block in place of a casting plug, which places a heating element directly into the engine coolant. This is generally the preferred method, as it’s the most effective.
The second type of block heater is designed to mount flat on the bottom of an oil pan. The heat travels up through the pan and warms the engine oil. These are effective, but only given that they fit the pan properly and are out of harm’s way. Some factory applications are designed like this, but aftermarket designs are intended to be “universal,” and they don’t always work as well. Familiarize yourself with the heaters you have in stock, and what they fit, or where you can locate an application chart. Most people shopping for a block heater will know they want one – it’ll be an easy sale – but getting the correct one for the application is the hardest part.
Tips for Your Customers
The best advice you can give your customers is explaining the importance of diesel maintenance. A critical tip, however, involves replacement of a diesel-fuel filter. When a diesel runs out of fuel, air is drawn into the lines, and they simply won’t start until the air is bled out. Cranking the engine won’t do anything except overheat the starter.
Some diesel trucks and heavy equipment are equipped with primers, such as those you may be familiar with on small engines. They’re designed to draw fuel from the tank and fill the filter and pump. Some newer vehicles have electronic primers that do this when the key is cycled on, but many diesel-powered cars don’t have either of these features. When the fuel filter is replaced, it needs to be filled with diesel fuel before connecting the lines. It often requires a small funnel, and it can take a few minutes to get it done, but it’s mandatory.
Seasoned diesel owners should be familiar with fuel-filter replacement, but it never hurts to ask and make sure they are. You can save your customer a lot of trouble.
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