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86 XJS v12 fuel pump problem -Help!

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J

jehiatt

Freshman Member
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1.The local auto parts and local library have no manuals.
2.My golf buddy changed his trans filter and now the car will not fire up. The fuel pump in not working. As I am the first responder for rides and repair help I need some info before I go over there with my volt meter and try to assist in this hot weather.
3. He jacked the whole passenger side up to get at the trans pan. When it came down the problem was there.
4.The cutoff in the door operates the red relay on the right fender well.
5. He has two fuse panels but declared that access and identification is difficult.
6. Went over there anyway and fuel pump relay in trunk is not pulling on, no voltage is on any incoming leads. Fuel pump will operate with 12v applied.

7. I could use a rundown on the path of the fuel pump wiring and fuse location - or other suggestion. thanks yall
 
The cutoff in the door is a collision sensor and will turn off the fuel pump via relays. The collision sensor can be reset by the push-in switch. If reset does not work, you need a schematic of the fuel pump circuitry that uses, more that one relay, most of which are found on the passengers side of the engine compartment near the firewall. I recommend a Haynes manual with schematic that is reasonable in price and available.
 
I had a similar problem with my 88 xjs the problem was within the main relay. my fuel pump, nor the ecu were getting power. hope this helps.
 
Until we get a manual we have to hunt the hard way. Where is this "main" relay. I have one on the very front right -inside fender wall that comes on with the key and will go on and off by operating the reset switch on the drivers door jamb area. Somewhere there has to be a fused 12v supply feeding the contacts also.
 
All built in (non inline) fuses have their function labled on the fuse box cover diagram. The positions for the fuse boxes and covers are on the passenger and driver side under dash (scuttle) panels. If you dont have these lids on the under scuttle you are in bad shape because they vary from year to year. If I were you I would have a manual of some sort (Haynes, etc.,) over nighted. The car is too complicated to play a guessing game.
 
Well i did find out the ECU controls the fuel pump relay. I did order a cd manual. meanwhile the boy is stranded.The car handbook is on hand and fuse locations are well marked but nothing said about one that supplies the pump relay +12v.
So in a few days I guess we will have the electrical "roadmap" to find our way home .tks yall.
 
So I got the CD manual ver 1.2. and it's missing vol 4 pages 125 & 126 which are likely the fuel pump wiring circuits in full color. It's also missing the pages 139 and up that are indexes and diagrams for several year vehicles.
The 1980 & 1983 diagrams that were on there are inferior quality and unuseable. The 1987% diagram was totally trash.
So - Back to square one.
 
Ok - I returned the CD manual. Ya'll ain't been too helpful either. It's not my car and if my Buddy can get it running again I think he will dump it fast. I would love to own and drive it, but after unsucessfully trying to help him get it going again ? No way - I think I will stick to GM type vehicles myself.
 
Make me an offer that I cant refuse to buy the XJS in present non-running condition. Where in GA are you located?
 
Dear Jack:

Tain't mine. Too late for best buy - besides - you have enough already.

AND:

I must apologize to all concerned - for one critical fact of this case was not known and thus not presented in my original inquisition. The unspecified piece of evidence was: that in addition to the right side of the vehicle being jacked up to change the trans gasket - the JAG would not crank afterwards because there was a battery problem.
The battery was too weak or bad and would not turn the engine over - so another battery was placed in the boot to do the job. It turned the engine over but the engine would not fire up.



Have you figgered it out now?




In the boot there were two brown wires in the battery compartment area - about a #10 and a #12 wire, with female spade lug connectors on them. The owner said that according to the owners manual those were the caravan connectors. From then on they were dismissed as relevant to our problem.

So last week I go over there again and look at this car some more and here is the battery sittin out in the boot and there is this small black plastic "bump" halfway back on the positive cable. Inside the "bump" are two male spade lug connectors. They look like they might hook up with the brown wire female spade connectors but the female connectors can't reach. They would reach if the battery is in the battery box and not in the boot. So we put the battery in the battery box, hook up the two brown wires, and the JAg fires up.

Recap;

So, when my buddy removed the battery from the battery box and placed it in the boot area to change it out - he also must have pulled the wires out of that connector - and didn't notice it or what ever. He never mentioned a battery problem until last week.

I could not see a fuse holder or such on those two brown wires in the trunk feeding the fuel pump and what ever else. Without the diagrams I have no clue but I think I would cut and add a ATC 30A fuse holder on those wires just for luck.
 
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