Drivability Issues
INTERMITTENT PROBLEM
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Problem solving tips Someone once said that a good technician is not expensive but, rather, priceless. Having said that, I note we have all spent way too much time on an intermittent problem to justify the hours spent on these types of problems. So you drove the vehicle for 20 to 30 minutes without a single stumble or symptom. It happens to all of us. Our best hope is that although the service we’re performing may not turn out to be all that profitable, at least we retain a good customer. There have been many times in my own experiences where I have finally duplicated the symptom and finally narrowed down the problem and fi xed it. Later on I go home and think about the tests I could have done, might have done or should have done that would have cut down the time on my diagnostics.
First things first!
Have you ever documented the symptom based on what the car owner stated only to find out that it was not an accurate description of the actual symptom? In addition, how many times have you needed to speak directly to the car owner to find out how often the symptom occurs and at what tem-
28
ASP
December 2019
By Bill Fulton
Figure 1: A DVOM’s Peak Detect mode will capture and record a 100 millisecond signal drop-out. perature and at what speed. In addition, when you have the MIL on, did you take the time to analyze and duplicate the freeze frame conditions? Many times during my live seminars I compare an automotive technician to a medical doctor. Suppose you have a medical problem and you go to your primary care doctor and you give him a complete and accurate description of your symptom. In the real world he most often is going to write a prescription for you to try and see if you get any improvement. That is what we call practicing medicine. Are we as technicians any different from the medical doctor? I don’t think so. However, in the customer’s mind
they don’t want to pay a technician to guess. But what do we do when we can’t get the vehicle to act up? Is there a pattern failure or a silver bullet? Can this be honestly communicated to the car owner? I have had to do it many times — with success. Have you ever addressed an intermittent lean code, and after reading the freeze frame find out that it occurred under steady road load conditions? The MAF sensor has been replaced. The fuel trims are double digit positive at all load conditions. The fuel pressure specs are good and all the sensor values are within specs. Making certain E-85 fuel was not used in a non-flex-fuel vehicle, can you honestly rec-
