Jaguar Repair: 87 XJ6 starting woes, propane gas, noid light

Question
Hi,

I've got an 87 XJ6 that was running fine but became a little harder to start over the course of a couple weeks.  Finally, last week I started  it, it ran for about ten seconds and just died...like someone turned off a switch. I could start it, but it would not keep running.  Now, I can't even start the car.  

In the past six months I've replaced the plugs, wires, dist. cap and rotor, fuel pump and filter. I also had to replace the ignition switch right before the car became impossible to start (switch prongs broke off). I was hoping that by replacing the switch it would fix the problem, too. It didn't.

I've got about a 1/4 tank of gas.  I've got fuel at the rail and the cold start injector is pumping gas (took it out and watched it as someone else turned the engine over).  I've got a strong spark at the plugs.  Compression is good, too.  I tried the propane gas trick at the air intake and it didn't do a thing.  I've ran a cable from the neg. battery to the engine block to check grounding...no change.   This thing just doesn't want to start.

I've read that if the tach isn't moving when I try to start it (and it isn't), then it could be a crank positioning sensor.  But I can't find one listed for this car.  

I figure I have a sensor that has failed.  Any advice on where to look first?

Thank you in advance!
Dave


Answer
Hi Dave,
Tell me what the compression readings were on each cylinder (throttle open)and what the cranking vacuum is (throttle closed) and purchase a "Noid" light (available at most auto parts stores and not expensive) and check injector pulse. (cold start valve does not count as it is not controlled by the ECU)

Since it does not start on propane, you have a problem in either compression, vacuum or ignition. If it will start and run for a few seconds read the vacuum and note if the vacuum goes to 0 before the engine stops turning (keep the throttle closed)

Try this, even though the battery is up, connect another good battery in parallel like you were jump starting a car with a dead battery. See if it starts and let me know.

Howard