1990 XJ40, 68,000 miles, was running fine, started after sitting a couple days while replacing a heater blower it ran maybe 5-10 seconds & stalled. Sometimes it starts for maybe 2 seconds. Sometimes it hits on a few cylinders but fails to start. New fuel pump, regulator, & filter, makeshift gauge on return side of fuel rail reads about 100 psi. changed MAF sensor & ignition module, Dist. cap, rotor, & wires replaced recently. All fuses checked, battery new this year. Any ideas?

 

Just an idea but maybe you disturbed the plug to the ECU when you were in there changing the blower? Try unplugging and replugging it and see if it makes a difference.

If you've got gas and spark and it isn't the ECU plug maybe the crank position sensor has quit or the connection/plug is bad or intermittent?

Another possibility is a major air leak in the intake plumbing between the MAF and the throttle body.

Anyway, some more things to check, good luck with it!

Larry

 

Thanks for the answer. ECU was not initially unplugged but we later unplugged it, checked for corrosion, reconnected plug, All connections appear good between MAF & throttle body. I didn't actually check crank sensor. I figured if it quit the engine wouldn't fire up at all. Was going to try another ECU but this car has a different number ECU then my other 1990 Jag or the 1992 parts car even though the book says 1990-1992 are the same..

 

Ok, maybe you should put the old rotor and cap back on and see how that goes and while you're at it re-check the firing order!

Larry

 

Problem solved. Water in gas. Seems quite unusual since it had been 5 days since I put gas in it & it ran fine until I parked it in my usual spot at the shop. That was a week ago. It's kind of embarrassing considering I worked as a mechanic for 12 years & taught or trained mechanics for 8 more.

 

Oh, oops. Glad you got it!