I have a 1991 xjs v-12. It is not getting fire to all the cylinders on the passenger side of the motor. I can smell gas but i don't see any leaks.The passenger side exhaust is much cooler than the driver side and off beat .This has happened in the past but only for a few minutes at a time. Now the problem is permanent. Any help would be appreciated. Thanks, Kurt

 

Kurt,

this will be on the ignition side of the circuit ,

the Marelli coil for that side has probably failed, it should be mounted on top of the radiator panel at the front of the car,

try swapping the plug from one coil to the other and see if the problem moves to the other side of the engine, if so simply replace the faulty coil pack

hope this helps

BB

 

I agree, sounds like a Marelli failure. Check the distributor cap and rotor, too. And don;t drive the car until its fixed or you'll have a real mess on your hands !

Cheers
DD

 

Thanks for the help and sorry for the delay. I Did try switching the coils around, i switched the wiring from the top coil to the lower coil but it didn't want to start. I then switched the coil wires at the distributor and it fired up with the same symptoms. Ive never had a coil go out on me and then be OK for some time after that. The coils thathave quit on me just quit. This happened three times before but only for just a few minutes than ran fine. Thanks again for your help. Kurt

 

The two coils are mounted on the engine valley cover. They can, and do, intermittantly fail. If you have the misfortune of a coil failing on a nice warm engine, it will overheata converter in very short order. Apparently Doug has read about how serious that can get. Two new factory coils and a little labor is about $300 that could save you thousands.