I purchased a 1976 XJS that was running at 50% i have had the injectors cleaned, replaced the spark plugs, ignition leads and rotor, then it was running at 80%. the engine was quite dirty so i decided to clean the engine with the air compressor and detergent, after this the car started but was running very bad and after a short drive around the block it stopped running. now it will only start and run for one - two seconds and just stop, after this it will just turn over, however if it is left for a few minutes it will start and run for one - two seconds again and then stop. i suspect it is an electrical fault as the fuel pump is working and there is plenty of spark too. can anyone help with some suggestions?

 

Welcome to the forum david1,

I've moved your question from General Tech Help to XJS forum. Members here with the same model will be able to help.

When you get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Bugga.

Cleaning these older engines in the manner you have has reeked havoc with a very looooong list of gremlins. Soooooo, fun will be had, trust me.

You will need to seperate EVERY connector, CAREFULLY, and fully dry them. Reassemble with some electrical grease (Diletric grease in some markets).

The EFI loom, in the bottom of the "V" is the #1 cause of running issues with these. It will be badly shorting internally, simple old age and heat have done this, and the cleaning has stirred it into submission.

Moisture on the inside the distributor cap will also reek havoc.

If it still has the Opus ignition amp in the "V", just aft of the a/c compressor, this thing hates water, FULL STOP.

The list goes on for many pages, so I will stop for now.

As I said you will need to systematically dry and check all those connectors, one by one.

 

Thank you for the advice Grant. I am working my way around the engine cleaning connectors. Got some dielectric grease as suggested.
I am getting 30PSI fuel pressure in the fuel rail, so I suspect the problem may lie with an electric signal to the ECU as you suggest.
I checked the resistance of the air temperature sensor and the water temperature sensor and they were both correct. How can I check the wiring back to the ECU for the air and water tenperature sensors? Got any tips on how to check the wiring?
I had a look at the ECU and could not find a connector plug. Don't want to disassemble the ECU to get to the wiring.
Got any tips on how to check the wiring?
By the way, the distributor cap was free of moisture. Cheers.