i have a 2002 XK8,that starts 8 out of 10times,,, I have a new key, works as good as the old one,, battery and connections checked,, starter checked,
lights on dash come on, but will not turn motor over.
But, if i wait 15 minutes, it will reset itself and start,,, if it stalls, i have to stop in traffic and wait 15 minutes for it to restart,, i have jiggled the trans but it wont help. Jaguar dont seem to have any answer either.
need help,, lol, this is disgusting,,,waiting 15 minutes for it to start...
i will appreciate any suggestions,,

 

Does it stall?

 

It doesn't sound like a security or key chip issue because if those were messed up the engine would at least crank. Same for a fuel flow issue. My next guess is a longshot, but it's a possibility. On my car the cable between the positive battery terminal and the terminal block mounted to front of the spare tire compartment wasn't making a good connection internally. It rarely caused a problem when driving, but when it did the symptoms were flickering headlights and dashboard lights. Then everything would suddenly go black, and the engine would stall. A second or two later everything would come back on, but I'd have a gearbox fault error on the dash and the transmission would be stuck in whichever gear it was in. I hooked up my OBD scanner to the car to monitor it when the lights would start flickering. The voltage was all over the place, going from 10 volts to 16 volts and back in half a second.

Then, every once in a while the car just wouldn't turn over when I tried to start it. It was as if the battery was dead. That might have happened once out of 30 times, and then later it would happen about one time out of 10. If I'd go back to the trunk and check the security of the battery lugs, I'd hear a "pop" when I jiggled the cable. It sounded like an electrical arc from inside the cable at the crimp. As soon as it made that "pop" the lights would come on and the car would start without a problem.

I thought that maybe I had a problem with the cable. I removed it from the car, put the crimped end in my vice, and cranked it down to re-crimp the connector. I haven't had a single problem since I crimped it. That was 6 or 8 months ago. Another member had a similar problem and did the same thing. To the best of my knowledge he hasn't had a problem since.

You can remove that cable, re-crimp the ends, and reinstall it in about 10 minutes. It's very easy to get to in the trunk. Just lift off the cover over the battery and the one over the spare tire. You'll see the cable that connects between the positive battery terminal and the bulkhead behind the tire. You might have to remove the tire, too. It might not fix your problem, but you will have at least eliminated that as a possibility.

Oh yeah... when my car wouldn't crank, if I just let it sit for a few minutes it would start right up, just like with your car.