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Weird problems.....

Hi all, I am trying this group as I have NO IDEA where to start. I have a

1986 XJS 12cyl. Problem: Car starts, but then dies when I let go of key, sometimes it runs for a while, sometimes she will not run at all. When she does decide to take a ride on 1/5 throttle she bucks like a bronce, a bit more on the gas and she seems fine, until about 4/5 throttle when she will die out completely. I actually have to drive it at 2500rpms in the rare instance that she runs at all. Any pointers will be greatly appreciated. I have not really check anything at this point. New purchase, so I do not have much history other than a "cheap and good" mechanic worked on her. Thanks to all.
Reply to
PeteR
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Make sure she get plenty to drink! There seams to be blocked filters for the petrol/gasoline. Also make sure all fuel injectors are clean.

Pepe "PeteR" skrev i meddelandet news: snipped-for-privacy@news.supernews.com...

Reply to
Pepe

Peter,

Sound to me like a classic Auxiliary Air Valve problem. This valve is located on the rear of the left hand bank of cylinders when viewed from the drivers seat. I will send a picture down to your email address to help. The valve controls the idling functions and acts a bit like a choke. They are always getting clogged up and need clearing. I did sort mine out by soaking it in WD40 and then boiling it in water until the valve cleared itself - But I suggest you make sure your wife is out when you do this !!!

Best of luck

Stu

Reply to
Stuart Adair

Ok. The saga continues. I traced it to the fuel pump not working correctly, and removing and replacing the fuel pump relay fixed the no run situation. then I took it for a ride and the transmission seemed to resist shifting into high gear. Boy am I starting to get cranky. Also, I noticed that the vacuum advance nipple doesnt have a vacuum hose attatched to it at all. Is this car supposed to have a maechanical advance? Or is it electronic?? Any help on a transmission suggestion?? Sigh.

Reply to
PeteR

Reply to
PeteR

The symptoms that you describe are those of fuel starvation. The possible causes are weak fuel pump, clogged fuel filter or malfunction within the fuel injection system itself.

Given the car's age I suggest you test the fuel pump's pressure and output volume. A "tired" pump is the likely cause.

V-12 experts may have a more concise suggestion.

Reply to
T.G. Lambach

Peter,

Glad to hear that things are running a little better. My V12 is a 1987 model and does have a vacuum advance fitted to the distributor.

Stu

Reply to
Stuart Adair

Reply to
PeteR

Reply to
PeteR

Peter, The vacuum advance pipe goes to the right hand bank of cylinders (Viewed from the drivers seat). It goes between the castings of the inlet manifold and underneath somewhere !!! On my car the pipe is black with a white stripe but knowing Jaguar parts that could be different on every car they made. I'm going to send you some pictures that might help.

Stuart

Reply to
Stuart Adair

Please check the coolant temp sensor is not reading erratically either. This is CRITICAL to the fuel supply. Wires perished can also cause many headaches - especially on a V12- intermittent open circuits, short circuits, high resistance etc.

COLD = 9000K Ohm (from memory.... i think it is in specs) HOT op temp = 200 Ohm.

HTH Nick.

Reply to
Nick

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