Question1984 Jaguar XJS wouldn't start after sitting for 3 years. After establishing spark (replaced module, cleaned connections) engine started, but wouldn't run faster than a slow (estimated 200 rpm) idle.
Fixed vacuum hoses/leaks, checked throttle pot (good), all injectors operating, all plugs firing, but no change.
Dies if throttle opened, and after 2 minutes idling will start to oscillate between faster and slower speed until stalling altogether with no startup possible (will "catch" but stall) until after some time at all
Did this remedy the problem? Thanks.
AnswerHi Kevin,
Your symptoms do not tell me what is wrong and I have rarely ever been able to diagnose any problem by symptoms. Testing it the only method I have been able to repair failures.
Even if you don't have the high tech Jag equipment for testing, you can use other methods. To be able to divide the car into sections and place the failure into a smaller section you only need to spray a fuel like "Starting fluid" into the air horns when you try to open the throttle. If the engine revs up with a fuel added to the air intakes, then you have divided it into a fuel related problem not a mechanical engine problem nor an ignition problem.
If it does rev up then you need to look at fuel supply. This requires that you put a "T" fitting in the fuel line and a fuel gauge to measure fuel pressure. (a lack of fuel pressure can cause the engine not to rev above idle) Should be about 30 PSI.
You should also purchase a Noid light (very inexpensive at most auto parts stores) (you need a Lucas or Bosch Noid light) this tests the pulse signal at the injector wire. The light should flash even when you open the throttle.
It may pay you to find a local shop that can run injector cleaner directly through your injectors since the car has sat for a 3 year period. The additives that can be put into the tank takes far too long to be of any use in your case.
If you find that the fuel pressure is low or goes away as you try to open the throttle would also indicate a possible stopped up fuel filter. (a common fault when an injected car is left sitting for 3 years)
Somewhere in the above tests you should find the section that has failed and thus narrow the problem to a smaller area.
Howard
