Although I’ve been working on and teaching how to work on cars for over thirty years I still sometimes make goofy mistakes, at least from the standpoint of wasting time.

Case in point is when I didn’t follow an absolute test procedure. To accurately test a vehicle there’s a very strict sequence, which must be followed to avoid mistakes. In this instance a new car dealer brought me a car that was running terrible. The dealer’s techs had done everything to get it straightened out but nothing they did helped.

Keep in mind this is one of those very rare dealers who actually has good techs. They had already done a ton of sophisticated testing and replaced every related part under warranty. After several days they were out of ideas and the customer was running out of patience. They thought perhaps a fresh perspective might help.

When the car arrived I connected diagnostic equipment and proceeded to test it up one side and down the other; nothing. This had used up a full day’s time but I was determined to find the answer. Being bullheaded about such things I proceeded to run a full battery of pinpoint tests. More wasted time because you guessed it, nothing showed up.

To find where I had gone wrong I reviewed each step I had taken and realized that I had begun at about step three of a proper test procedure. I had made an assumption. I assumed the dealer techs had done all the basics. Hours of time wasted!

I hadn’t done a visual check of the basic components so I started removing and looking. The coils were fine, the PCV valve, air filter, coolant temperature sensor, mass air flow sensor and throttle body; everything looked great. My last step which should have been one of my first steps was to remove the spark plugs. Although they were brand new the tech who installed them had made a boneheaded mistake, he hadn’t adjusted the gap. Checking and adjusting the gap on every new spark plug is imperative. Plugs get shipped all over the world before they’re used and a lot of things can happen.

In this case the plugs were gapped wrong. Although I didn’t think this would be the fix for such a tough problem, I set the gap to spec, reinstalled them and started the engine. Amazingly the problem was gone, completely gone. To prove the point I took the plugs back out and adjusted them to their original setting and the problem came back. I had solved the problem from Hell with a simple adjustment of the spark plug gap.

The lessons here are, don’t be afraid to question your technician about what procedure will be used to check your car. If the procedure starts with a thorough inspection of the basics rather than a code scan or an expensive test, you’ve probably lucked onto a good tech. Keep in mind that dramatic problems are often caused by tiny deficiencies and they don’t always require expensive fixes.

© Copyright 04/27/12 Pat Goss all rights reserved, 507 words.


Write a Comment

Fields with * are required