Where is the fuel pump? '78 XJ12L

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jjv5.jjv5@gmail.com - 22 Feb 2006 22:12 GMT

I have a 1978 XJ12L that has been converted to a Chevy V8. It was
running and died all of a sudden. I have a clear plastic fuel filter in
the line after the mechanical fuel pump at the engine. It gets no fuel.
I suspect the tank fuel pump. I cannot hear any such pump with ignition
on. I think I should be able to. But, where is the blasted fuel pump? I
suspect they're in the tanks, but I really hope not. I cannot find the
pump in the trunk, like so many other Jags apparently. Anyone have this
same car and replace the fuel pump?

Thanks for any help.

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Chris Halpin - 23 Feb 2006 04:01 GMT

The fuel pumps are the submerged type mounted in the fuel tanks.
To get at them it is necessary to remove the rear tail light assemblies.
They have a locking ring holding them in place. Before undoing this it
is important to be sure the fuel level is below this point or you will
spill a lot of fuel.
A problem I had was the filter gauze was blocked by rubbish in the
bottom of the tank.
I have assumed that you have tried changing over the fuel switch to the
other tank. If you still get no fuel it is possible you have a blockage
of some sort.

Hope this helps

Chris

> I have a 1978 XJ12L that has been converted to a Chevy V8. It was
> running and died all of a sudden. I have a clear plastic fuel filter in
[quoted text clipped - 6 lines]
>
> Thanks for any help.

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jjv5.jjv5@gmail.com - 23 Feb 2006 11:36 GMT

Thanks very much. That's very helpful.

> The fuel pumps are the submerged type mounted in the fuel tanks.
> To get at them it is necessary to remove the rear tail light assemblies.
[quoted text clipped - 21 lines]
> >
> > Thanks for any help.

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jjv5.jjv5@gmail.com - 24 Feb 2006 13:26 GMT

Well, the pump is not actually in the tanks. I removed the tail light
assembly and found the fuel level sending unit - not the pump. So I
took the whole tank off. Most definitely there is not a submerged pump
in there. Plenty of rust, but no pump. As far as I can tell the pump
must be located between the forward-most part of the trunk and the rear
axles, buried up under there somewhere. I have only recently acquired
this car and can't get it off the ground enough to slide all the way
under and look.

Anybody have an actual 1978 XJ12L and found the fuel pumps somewhere?
I'd love to see a picture.

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John Hudson - 24 Feb 2006 14:50 GMT

> Well, the pump is not actually in the tanks. I removed the tail light
> assembly and found the fuel level sending unit - not the pump. So I
[quoted text clipped - 7 lines]
> Anybody have an actual 1978 XJ12L and found the fuel pumps somewhere?
> I'd love to see a picture.

Oh well, at least you know where the senders are:-). I don't have a SII but
according to the Haynes manual if you look inside the rear wheel arch at the
front of the tank you'll find a cover that gives access to the pumps. You'll
need to support the car on stands and remove the rear wheels. to get to the
pumps. Watch out for a non-return valve in the fuel line. The pumps were
made by AC Delco and are not repairable but are identical to those on a
Chevy Vega I believe.

Signature

regards,
John Hudson
Brisbane Australia
71 SI XJ6, 85 SIII XJ6

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ogglet - 24 Feb 2006 19:52 GMT

>> Well, the pump is not actually in the tanks. I removed the tail light
>> assembly and found the fuel level sending unit - not the pump. So I
[quoted text clipped - 16 lines]
> and are not repairable but are identical to those on a Chevy Vega I
> believe.

The pump is in the tank, but in the bottom. It is part of the little outlet
pipe. You can get to it reasonably easily by removing the screwed cover in
the rear of the rear wheelarch. Or by removing the fuel tank. Which in my
experience is not a task to be taken lightly...especially putting it back.

If I remember corectly there is a retaining ring which needs to be removed
before the pump and gauze filter can be slid out. Note there is a non return
v/v also in the rubber pipework.

If your car is an earlier series 2, then the pumps are in the boot. But a 78
should have the submersible pumps.

cheers

ogglet

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ed - 26 Feb 2006 01:43 GMT

On a Chevy V8 though is there not a mechanical fuel pump on the front left
(looking from the front) of the block?

> >> Well, the pump is not actually in the tanks. I removed the tail light
> >> assembly and found the fuel level sending unit - not the pump. So I
[quoted text clipped - 32 lines]
>
> ogglet

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jjv5.jjv5@gmail.com - 27 Feb 2006 15:00 GMT

Indeed there is a mechanical fuel pump. I did not realize this was the
only fuel pump needed for that engine. On my truck I have pumps in the
tanks and a pump at the engine, but it's fuel injected. The Chevy V8 in
this car is carbureted. There are cut wires in the trunk and the fuel
hoses coming from the three way valve and other areas look very new. I
guess the fuel pumps were in the trunk but were removed since they're
not necessary. Good for me. The Chevy mechanical fuel pump is about
$12.

Thanks for the helpful replies. Taking the tank out was pretty simple,
only took about 15 minutes. I'm going to give it the POR-15 treatment.

> On a Chevy V8 though is there not a mechanical fuel pump on the front left
> (looking from the front) of the block?
[quoted text clipped - 38 lines]
> >
> > ogglet

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