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Last week a customer brought in a beautiful 1995 Jaguar V-12 that ran terrible when you put the “pedal to

Last week a customer brought in a beautiful 1995 Jaguar V-12 that ran terrible when you put the “pedal to the metal”. He had been working on it trying to find the problem for over 6 months. Several auto repair shops had looked at it and did several things that made it run some better, but not good enough to make it “Better”. Whenever a customer brings in a car with this scenario I suggest that they should take it back to the repair shops that had worked on it. This is to give them another chance to “Make it Right’ since he paid good money for them to fix it. I knew that if I took in this job it was not going to be easy since so many shops had tried and failed before me. I thought I would scare him away with a 3 hour diagnostic charge plus any parts that may be needed. To my surprise he handed me the keys and signed his ticket and he went home for the night. The next day I had my technicians check all the basics such as fuel pressure, fuel volume and static pressure. The fuel pump passed with flying colors since it was one of the new parts that had been installed. Engine compression was good and even and all the spark plugs and wires were good as well. The coils were working as they should and all was well electrically and mechanically. When the tech went to the computer to access it with a scanner, that’s when I saw why the other shops had problems. It was a 1995 model which is a “weird year” on scanners. Most generic scanners seem to skip this year or there is little or no information available. As luck would have it my scanners could not access it either. I told my techs to continue to look at the basics. I needed to know what the 5 gas readings were on the left bank and the right bank of the engine when it was at idle and @ 1400 RPMS. To my surprise the right bank was running richer than the left bank. Every spark plug on the right bank barely changed the engine rpm when each plug wire was disconnected one at a time. The left bank RPM’s had big change when each plug wire was pulled. Since there was no communication with the scanner I told my techs to check the O2 sensor operation with digital volt meter. To my surprise both banks were switching like they were supposed to switch. This told me the computer was able to control the amount of fuel the engine needed. That’s when the light bulb went off in my head to clean the injectors chemically. Once my techs hooked the injector cleaning machine to the car, the car started to run terrible. This told me I was on the right path to a solution. After cleaning the injectors 4 times, the engine ran great and performed well. The moral to this story is with perseverance and common sense you can fix most drivability problems on today’s or yesterdays vehicles. Live long and prosper!

 

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