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Starting Saturday, November 5, 2011
FAQ # 00
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Ever heard of "junk in = junk out"? That's true in the auto repair industry as well and VERY true here. I am only as good as the information you give me. In spite of the fact I can guess right with the best of them, I have limits. I cannot tell you where your oil leak or water leak is coming from. I cannot tell you what a smell, a vibration or a noise is. But I have written FAQs about those issues with the very best advice I can give you on how to find them, what to look for, and how to isolate the issue. PLEASE read on.
Before you start guessing or ask me to guess, it is important to know that guessing is generally a very bad idea. EVERY DAY I get an e-mail from someone who has spent hundreds of dollars trying to fix a miss or a surge and still has the problem. You should know that it will cost between $75 and $175 to have someone properly diagnose:
It is OK to tell the repair shop upfront, "I love to work on my car myself, but in this case I don't know what to fix. I want to hire you to find the problem and then decide if this is just a part or something I can repair on my own." At this point the shop knows they better be right on their diagnostics because once you replace what they said was wrong and the problem isn't gone, they know you will be coming back looking for your diagnostic money back or a recheck.
What is important, is to set the estimate parameters. It is OK to sign the repair order and after your name, write "OK to $75" or "For estimate only and up to $150". Heck I do that all the time. Ask them, "How long does it normally take you to find my oil leak?" They may say "We can do that well within an hour." You say, "Please put everything is dollars for me, how much is an hour? Then say, "What happens if they don't find it after spending $150 of my money, what are the chances that will happen?"
You have to understand that I can't help you or even guess on the repair until you can tell me if the problem you have is spark or fuel related. THE FIRST THING any tech has to do is determine if it is spark or fuel related. Here's some help:
You must find out if your problem is cause by the absence of spark (pickup or crank sensor, module, distributor, coil, wires, plugs) or the lack of fuel (lean) or the abundance of fuel (rich).
Until you do, you are spinning your wheels. I see repair orders all day that have a fuel pump, then a coil, then an injector, then a crank sensor. That tells me someone had no idea if the problem they are chasing is spark or fuel. Here are some clues:
The classic symptoms for this problem is where the demand for fuel exceeds the vehicles ability to provide fuel. Otherwise you are asking for more fuel that can be delivered. So cruising down the street at 30 mph and having the engine die is most likely a spark problem IF the car can then immediately start and go 55 to 75 mph. Common sense says that if enough fuel can be delivered at 75 mph, then going 30 mph should be possible.
If you have a fuel related problem, 90% of the time it is the LACK of fuel that causes your problem. If you suspect you have a fuel problem, change the fuel filter first and before you install the new one, blow through the new one and the old one and compare the two. That small amount of gas on your lips is worth it knowing if the filter was plugged solid or wide open. If it was plugged, we're making progress, if the old filter was wide open, you know before you finish the job, that you have done nothing to make this problem better. If the old filter was plugged, drive the car. If it is better or worse, we are on the right track. We are looking for change to tell us we are on the right track.
Most of the time if your car has an in tank fuel pump, the level of gas in the tank and the ambient temperature will have an effect on when your problem happens. You see, we use the gas in the tank to lube and cool the electric fuel pump. If the tank is near empty and the fuel pump is weak, it may cause a dying, surging or stalling problem. When the tank is full and the fuel pump is submerged, the problem is gone or is less intensive.
If the problem is still there, go to a local hardware store and buy a small tank of propane and a attachment that allows you to solder. Unscrew the end of the brass flame maker and attach a long piece (10 feet or so) of 3/8 fuel line to the end of the brass pipe with a hose clamp. Place the tank next to your right hip on the front seat and take the long hose out the passenger side window and through the hood crack and into the duct work where air flows into the engine. Sometimes we simply lift the air filter up and snake the hose towards the engine for 18 inches or so. Then take off in your car and get the problem to happen. When it does open the valve on the propane tank about 1/4 to 3/4 of a turn, NO MORE. Now, by adding fuel to the engine, by giving the engine another source of fuel, does that change the symptoms, is it better?
By adding propane, you will temporarily fix plugged injectors, weak fuel pumps, bad vacuum leaks, bad EGRs and defective sensors (O2, TPS, MAP, MAF, Coolant) that are lying to the computer about what they are seeing causing the computer to command a lean condition even though more fuel is actually needed.
Testing the fuel pressure on Monday after the engine dies on Sunday on the way up a steep mountain is a hug waste of time. The problem has to be there in order for someone to find it.
We can't find and fix what isn't there when we're looking.
Now I haven't covered all of you with water in your tanks, bad grounds to the fuel pump or relays, bad distributors that tell the computer the engine has died, when it really hasn't, so the computer shuts off the fuel pump at 55 mph or cars with grounded injectors that cause havoc with the injector drivers inside the computer.
A rich condition causes black smoke, poor fuel economy and makes the catalytic converter stink like rotten eggs or sulfur. This is always caused by a bad O2 sensor, a leaking fuel pressure regulator, a bad MAP or MAF, a leaking injector or any of the other 5 sensors that can cause a rich condition. I must say, fixing a rich condition requires a scanner and vast knowledge of how the system works, I would leave the rich running engine repairs to the experts.
The symptoms here are slightly different. When you have a spark problem, it can be made worse by high humidity. Try spraying the engine with water, then driving it. If your engine runs worse in wet weather, it's likely to be spark related. Temperature will also effect spark and most electrical problems are temperature related. It is also true that some fuel problems only appear when the temperature is really hot, but running out of fuel climbing a hill on a hot day is different than cruising down a flat road on a hot day and having the engine die. The demand for power and fuel is the obvious difference.
But engine misses, surging, dying, stalling can be caused by coils, plugged catalytic converters, anyone of 25 sensors and signal generators, bad electrical connections (very common), bad computers (rare) or bad cap, rotors, wires or plugs. Transmission problems and A/C problems can also create problems that LOOK LIKE spark problems.
This is a very bad idea. You see it makes no sense to tell the shop what to do or tell them, "The guy on the web said . . .". The recipe for success is simple. Give them the symptoms, write down what you see, you hear, you feel, you smell and make sure they know you expect them to diagnose it correctly. If you tell them what to do, or what to fix, if you are wrong, they are NOT going to refund you a dime and they shouldn't.
Here's my favorite story. Wife brings in a red T-Bird. Tells the service writer her husband said to tune it up and align the front end. Service writer asked for symptoms, asked to know what they knew, asked why and wife said "Because my husband said". Estimate given $135, and accepted. Car delivered Tuesday, hubby back Wednesday morning with underwear all wadded up. He is yelling and demanding to see the owner.
"I paid you $135 to fix my car and I still have the same problems"
I said, "No, you paid us to perform 2 tasks, to do specific work. We never knew what you knew, we were never told about any problems."
Hubby said he still had a vibration and the car still surged. A test drive with Hubby showed a bad rear tire and the engine was surging because the A/C was low on freon and the A/C compressor was cycling on and off causing a surge.
I said, you diagnosed these two problems yourself and you were wrong. You should have just told us about the vibration and the surge and told us to find and bid the repair. You didn't. I'm not going to refund you a dime, because I'm not going to pay for your mistake. Heck I pay for enough of those myself, without paying for yours too.
The moral? GIVE THEM THE SYMPTOMS, NEVER, NEVER TELL THEM WHAT TO FIX. Then read FAQ # 10 for when they call you with an estimate.
You have 4 choices:
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