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Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 20396
Experience:  BEng hons Mech engineering, in auto industry 22 years
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My car will not start intermitantly as if it has been immobilised.

Customer Question

my car will not start intermitantly as if it has been immobilised. Leave for 10 minutes to 2 hours and it starts again
Submitted: 5 months ago.
Category: Jaguar
Customer: replied 5 months ago.
It is an XK8 1999. the problem used to only happen every 3 or 4 months and start within 5 minutes but now it can take up to 2 hours and happened 3 days in a row. you turn the key, the lights come on and a scrolling of emergency warning messages start. The engine does not make any sound and is not attempting to turn over. I used to get out, relock car unlock and try again a few times and then sometimes it started. often happens after a long run , when i come back to the car later in day. Not weather related. Low mileage on car
Expert:  Shantal-Mod replied 5 months ago.
I'm Shantal and I'm a moderator for this topic.
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Customer: replied 5 months ago.
I have not found an answer as I was waiting for "Matt " to come back in the 24 hours promised?
Expert:  Matt replied 5 months ago.


1st thing to check is that the main battery connections are tight and clean and if they are I'd consider replacing the battery if its more than 3 years old

I'd also check the condition of the high power start relay and fuse in the box under the bonnet

and they are also prone to flooding on a hot start

try starting with foot hard down on the accelerator when cranking and it will not fuel the engine and should clear out any excess fuel - although i think your issue is unrelated to this as you say is doesn't even crank ?

Customer: replied 5 months ago.
I had the battery replaced last August 2015. The terminals are very clean and attached by an RAC mechanic last time it would not start. It is not a hot start issue as the car had been sitting for 6 hours on Monday afternoon, and 5 hours on Saturday evening when it would not start. The is the first time in 9 years that it has happened 3 days in a row. Normally it was every few months or so and would start after 10 minutes. Last time it was 2 hours.The engine is not cranking at all. There is no sound from the engine as I said before , just the lights come on and the warning messages start scrolling through. it is as if it has immobilised itself. I get out, lock it up, wait 10 minutes or so, unlock, try again. his used to work and it would start but now it takes a lot longer......
Expert:  Matt replied 5 months ago.



there's some high power fuses to check next in a separate box at the back of the engine bay see the diagram

I've also included the current flow diagram for the starter

Expert:  Matt replied 5 months ago.


do you still need help?

Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you

Customer: replied 5 months ago.
checked the fuses per your diagram and they are fine. do you have any other suggestions?

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