Hi Everybody: Boy do I need your help. I have an 86 XJ6 that will not start again after shutting down. I can drive for 2 hours (for example) and it started beautifully, drove and idled smoothly. Then I stop for lunch and it won't start again. It just cranks away. I can wait 2 hours and it starts right up again!! To me, it seems like there is an electronic component that needs to cool down. Here is what I have replaced so far: fuel pump and filter, ignition amplifier, distributer cap w rotor (kept orig condenser), coil, temp sensor, water sender, and fuel pressure regulator. Some of those items were for a previous fuel related issue. I recall when I restored an MGA, that I had the same wait and go issue. I new pertronix coil solved it. Can the new coil from SNG Barrett be defective? I put a test light on it while cranking and both terminals gave a steady glow. When running again, I got the same results. I love this car guys but Im getting pretty down about it Any help?.

 

Sorry to hear that! Generally best to start with the basics - spark, fuel, air, compression...below is a link to a great faq on what you need to test and how to test it. Especially on an older car where there could be ground/other issues, new parts don't always equal results, so it's best to test when possible. Ideally, you should recreate the issue (i.e. drive, turn it off, and confirm no start), then proceed to the spark-fuel tests.

https://www.jaguarforums.com/forum/x...tart-xj6-2038/

Also, here are directions I got from Doug to test the Thermotime and Coolant temp sensors which are other possibilities.

Coolant sensor for the fuel injection:
Next time the engine is in no-start mode remove the plug from the sensor and use a paperclip or similar to jump the terminals. If the engine now starts, bingo. Jumping the terminals sends 'fully warmed up' signal to the computer.
Or, for $20 and 10 minutes time you can replace it. As guesses go, that's rather painless.
If you have an ohm meter you can spec test it

Thermo time switch:
The TT grounds the cold start injector which itself operates only with the key turned to 'start'. A fault here could cause impossible starting by flooding the engine but it wouldn't cause the engine to stall when running.
Next time the engine is is no-start mode unplug the cold start injector and see if anything changes