Hello all.

I've just joined the forum in the interest of helping my girlfriend get her '90 XJ6 running and keeping it in good running condition.

I've got plenty of mechanical experience with cars up to about 1978 but very little experience with anything as electronics-dependent as these Jaguars are.

- At the moment the car will turn over and occasionally will catch during turning over but doesn't come close to running.

- When I turn the key I can hear the pump engage and then disengage which I understand is normal?

- I have checked and cleaned the cap and rotor.

- Battery is fully charged.

I still need to check on injector operation with a stethoscope and check that the inertia switch hasn't tripped.

I've read a lot of posts here on no-start scenarios and the CSP issue comes up a lot. When I crank the engine the tach jumps up to maybe 100 rpm. Does that indicate that the CPS is working? Is there another way to check it, e.g. continuity with a multimeter?

In the posts that I've read I've seen a lot of partial troubleshooting suggestions but I'm wondering if anyone has posted a comprehensive no-start troubleshooting guide.

Looking forward to seeing what you guys come up with!

Chops

 

There are a few things it could be but if it has gone from running fine to suddenly not wanting to start it could be the ignition module which is located under the coil, small black box with plug attached. First check that it's tight (has to be tight to properly earth), if it is then find a replacement.

 

Thanks Leigh. I'll add that to the list of things to check next time I'm over there.

The car was (apparently) running just fine and then one day decided not to start.

 

In the meantime:

1. Is there a way to test the CPS?

2. Is there a troubleshooting guide posted anywhere in the forum?

Thanks!

 

If its "trying" to start the cps is ok. If its a bad CPS you will not have spark. They can be checked by using an ohm meter at the connector. I am leaning towards a fuel issue, from your original post.

Here's an easy check for you to do. Open the gas filler cap door, look around the rubber that surrounds the gas cap. Is it dry? There is a little hole within that rubber lining that drains water out, that gets in there via the door. Be sure its not clogged. If you have any water in that gas tank, you will chase your tail till you want to pull your hair out. Your car will not start no matter what if there is any water in the lines.

Your fuel pump may be flaky. The filter may need changing as well.

There is plenty in the XJ40 on no start issues, via the search within the XJ40 forum.

 

Thanks mrtalkradio. I've done quite a few searches but hadn't seen anything that specifically mentioned a procedure to test the CPS or a full troubleshooting guide. How do I check the CPS with an ohmmeter? What should the reading be? Assuming there is water in the tank and I guess the fuel system how do I get it out? I noticed the position of the filler opening and figured it was a recipe for disaster. All it takes it some dirt or leaves to plug the drain and suddenly you've got a big problem! Perfect example of esthetics over practicality I guess. lol