I am near-certain that it is the factory OEM alarm system is faulty after the car needed to be jumped. EVERYTHING else has been triple-checked air/fuel/spark. The car almost starts but then doesn't. This happened after the alternator died and the car was jumped a couple of times.

1. Does anybody know how to bypass the factory alarm system permanently, please?
2. If 1. can't be done. I was told the alarm module must be programmed to the VIN of the car (US model)? True/False? That is, buying a used module will not work without programming.
3. Does anybody know if there are still people who can repair the existing alarm module or reprogram a used one to talk to my car?
4. Same question about programming a DPP 1131 AB Automotive Electronics CPU for the car: Who is left who can program/repair such?

Regards, Bo

 

Why do you think it's the alarm module? Is it because you're certain all other systems are functioning normally and there's "nothing else it could be" or is there something that indicates the alarm system failure? Can't say I've run across any other XJ40's with this apparent problem.

Sounds like you MIGHT have a weak spark, is the spark at the plugs nice and blue or a bit orangey?

 

Strong spark. Two British mechanics have confirmed that.

 

Well wouldn't a failing or failed alarm module disable the spark? And the rev counter shows around 200 rpm when cranking?

 

Are all the fuse box harness plugs firmly seated? The MAF plug clean and plugged securely? How about the temp sensor? A failed $10 temp sensor can really screw up the car.

 

it looks blue. is there a way to measure the voltage?

 

If you have blue spark at the plugs, the ignition system is fine. Are you sure enough fuel is getting through? The pump runs? Have you tried starting the car on ether? Is the throttle opening? Do you have air? Is the intake/air cleaner without a blockage? Are all the vacuum lines intact? Is the corrugated hose at the intake pinched at the throttle body?

BTW most British mechanics, unless they have experience with this actual model will not necessarily be any better than any other. IME most "British car specialists" either know old carburetted classics or OBD2 cars. Very few will be familiar with the OBD1 systems used on the XJ40 as they can't plug the car into their scanners.