QuestionQUESTION: Ive bought a xjs v12 after its stood in garage for 9 years but cant get it to start . Ive no power/pulse to one side of injectors and no power to electric fuel pump . Ive checked and replaced the main and fuel pump relays in the boot . If i put a wire direct to the pump from battery then it works so i know pump is ok . I would be very grateful of any assistance as I am lost from here .
ANSWER: Hi Vince,
I am not sure how much difference there is in the UK version of the XJ-S but I will try to help.
Since you have no fuel pump nor injection pulse I would start at the main relay in the trunk (boot). Turn the ignition key to "ON" (not start) and check for power on the white wire on pin number "86" on the main relay. It should be powered in position 2 and 3 of the ignition switch.
If it is not powered, then check the EFI main switching relay. (first relay on the second row of the left component relay panel under the dash.)
If you get nothing out of that relay you need to check the inertia switch (far left under the dash) The inertia switch does not supply power for the EFI relay but supplies a ground for the electromagnet in the EFI relay.
Let me know.
Howard
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QUESTION: Hi Howard thanks for your reply i will check tomorrow what you have said and let you know . So far ive changed about 5 relays for new ones and ive changed the ones in boot plus ive put noid light to check injectors and thats how i found the injectors work on drivers side but not on passengers side . Would the pump and injectors be linked on same wires or relay ? When you say to check the EFI main switching relay where about is this ? because there are a couple of relays under passengers side dash with the fuse box and there are a row of relays under the bonnet in front of car plus a row of relays on inside of passengers front wing
ANSWER: Our earlier XJ-S cars did just have one inside fuse panel and the main relay on them is not powered by a switching relay but powered directly by the inertial switch.
But you still need to test for power on the white wire on pin 86 on the main relay with the key in the on position.
You may run out of money if you keep throwing parts at it before you find out what is wrong.
I always had to follow the trail of electric to find a problem. symptoms are too often misleading and useless. Testing is the only true 100% method to find a problem.
With only one in-car fuse panel it comes closer to matching our "before" 1988 versions. I have 3 different diagrams of the before 88 version. They only have minor differences.
One is up to Vin #133460, second it 133460 with purge modification kit and the third is from 133461 to 139052. I don't know if those are US numbers only or not.
Let me know.
Howard
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QUESTION: sorry i should have said this is a 1989 and there is a fuse box under the dash on both the passengers side and drivers side plus there is also 2 small fuse boxes on inside of front passengers wing along with a row of relays
AnswerI have an 88-up diagram posted on my web site. Take a look at it to see if it matches your car and run the tests I outlined if it matches.
http://mg-tri-jag.net/88SIject11x1.jpg (half of it)
http://mg-tri-jag.net/88SIject21x1.jpg (other half)
Howard
