Hi folks,
First post on here, so please be gentle with me!
Well this is a first for the XJS, having never done this to me before.....
So, started the car this morning, fired up immediately (as normal), ran for less than a minute and before I could back it out of the garage it died.
The car turns-over but will not fire.
Fuel or electrical? Dunno....
I’ve taken the boot panel out and the relay nearest the tank ‘clicks’ after a few seconds on switch-on. There is no noise coming out of the pump? I’m sure they are noisy when the car is running but not sure pre ignition?
checked the other relay next to the pump relay and measures OK with a meter and doesn’t look corroded.
a bit of background... car very rarely gets used, only for classic car rally’s here in Cyprus.
However, just last week I used it for approx 100km and all was fine,
Thoughts anyone? What should I tackle first....

 

Firstly, welcome to the Forums.

Please do an Intro in the New Members Area when time permits.

Also, add your vehicle details via the CP tab, then the next line is not always asked.

You show a 1989 V12, GOOD. That is a change year, and is when the infamous Marelli system came in.

VERY simple identification.

Have a look at the top of your Left Inlet manifold, and there will, or will not, be a Black Box with "Lucas AB14" sticker on it.

If that black box is present, you have a Lucas car, NO Black Box, is a Marelli car, very important.

I wrote a "sticky" at the top of this section that covers a lot of possibilities.

My thinking as I type:

Fuel pump is dead, or dying, as you SHOULD hear it for 2 -3 seconds every time the Ignition is switched ON.
Fuel filter is way past its use by date, thus overloading the fuel pump ,and killing it.
The enertia Safety Switch has tripped, or simply needs to be reset, they are "female" and go hissy sometimes. Not sure where they are on a LHD car, ours are on the A Pillar, just near the drivers Right knee, under a plastic cover. All of 10 seconds to reset. Pull UP the plunger, push Down the plunger.

The list can get very long, but some very simple, systematic diagnosis will shorten that list a heap.

Let us know what YOUR car is, and then the fine tuning can begin.

 

Hi Grant,
Many thanks for the quick reply ...
oK, so I read the document.. Very thorough and excellent I must say, so went straight to the fuel filter. Put a long handled screwdriver to the filter whilst my wife turned the key to ignition.. I expected to hear at least a small 'flow' of fuel.... Nothing!
Then took off the fuel filter exit pipe expecting and ready for a burst of fuel.. Nothing.. A little dripple!
Then took off the filter input pipe and still not exactly a burst of fuel but enough to spill into the tray I put underneath... Then the brown gunk came out from the filter.. Wow is that supposed to be fuel?.. Clearly not right!
I did my best to 'clean it up' by feeding fresh fuel into it and then refitted it ..fingers crossed!... Nothing! So I took it off again... No pressure and NO fuel in it... so I guess it's pointing to the fuel pump! Obviously a new filter too.. Is there anything else to it?..
Thoughts anyone?..

 

Hello Kmas

I think it is fair enough to say you have fuel cleanliness issues. I would also attack the surge tank which is below the battery box. On the end of the exit pipe work there is another filter. There is a high chance this is dirty as well

Below is a photo of my surge tank and the in tank filter (it had fallen off - I am going to say thankfully)



Its not a hard job to do - hardest part is getting the fuel out of the system and there are a few different theories out there. Filters and tank gaskets are cheap, fuel pumps are not

Have fun

Cheers
Steve

 

Well done.

You have a pump not working.

BEFORE spending money.

Expose the pump, under the tin covers alongside the battery. On the bottom of the pump are 2 wires. One is power, the other is earth. Get some wire, with terminals, and remove the 2 wires from the pump, attach the 2 new wires, and connect direct to the battery, +ve to +ve etc, basically "hot wiring" the pump. If it works, there is a power issue, If it dont work, and all you get is a decent spark at the battery, the pump she is dead.

IF IT RUNS.

2 relays, up on the side. One in a RED block, the other in a BLACK block. The RED block is the MAIN relay. The BLACK block is the Fuel Pump Relay.

Take a voltmeter, or a test light, and probe the lead you removed from the pump +ve terminal, NOT the black wire. And turn ON the Ign and note the volt reading, or the light flash. It will only last about 2 seconds before the ECU turns that relay OFF.

IF you get a power indication, the relays are fine, and the pump she be dead.

IF you get NO power readings, you have either:

Relay issue, remembering the RED relay turns ON the BLACK relay. The relay in the BLACK socket is a standard 5 pin relay with 2 X 87 terminals, NO a,b,c suffix. The relay in the RED block is also a standard 5 pin, BUT it has a diode inside in case a battery in connected wrong, as in jump starting etc. They are NOT unique to Jaguar.
The ECU is having issues with the earth of the BLACK relay, and that is the ORANGE wire coming out of the BLACK block.This is NOT common with the 16CU ECU in your car.
The Inertia switch is tripped, playing up, lazy. Join the 2 wires at that switch for testing purposes ONLY, and thus eliminating the switch from the thoughts until the beast runs, then reconnect them to keep your authorities all warm and fuzzy.

Nearly midnight here, so i will catch up on the next phase of the planets.

 

To clarify, did you check the electrical circuit that operates the pump as per Grant's write-up?

But, yes, the pump has probably died. Old age and exposure to cruddy fuel.

As mentioned, and as you realize, you have a problem with the fuel which needs to be addressed before replacing the fuel pump...as the contaminates (rust, likely) in the fuel may harm the new pump.

FWIW, Series III owners of install pre-filters ahead of the fuel pump to protect it from residual and/or future contamination. Just a thought.

Cheers
DD

 

Ok folks, thanks for all the feedback.. This has been a massive help! It is without a doubt the fuel pump... I've now taken it off and ran it directly onto a spare car battery (charged of course!).
The pump is dead.. Siezed to be more exact, and gets very hot too!.. So being inquisitive I've taken it apart!... The bearings in one end are siezed and took significant force to release them. So it's a new pump and filter for me... Along with a clean out of both tanks and a new filter for the leader tank.
Thanks for everyone's help.. The piccy's on the small tank helped too! Problem solved, seems in some ways I got off lightly, nice and easy to resolve.
I do have a question on the pump though... More of again being inquisitive... Does anyone know how these pumps work? Does the fuel flow (or is drawn) around the edges of the unit.. Between the inner motor and the outer shell? There are seals that seem to isolate the elecrical elements from the inner and outer casing.. As I'm guessing you wouldn't want fuel running through the motor itself!.. The gaps between the two 'parts' is very small. It's an unusual design.

 

BEER, dont forget the BEER, you MUST keep your fluid up, or things will get fuzzy.

WELL DONE, and WELL DONE on the preventative added work. Doug is SOOOO right there.