[xj40] XJ40 fuel pump replacement

XJ40
1

Does anyone have recent experience of renewing the ‘‘in tank’’ fuel
pump on the XJ40? My car cut out when the fuel got low the other
day and I was told that the pump is probably on its way out,
especially as my car (a 1992 3.2) has done 143k miles. Apparently
the symptom is cutting out when fuel level gets down to about a
quarter of a tank and is too low to cover the pump and to cool it.
My local garage are nervous about doing the job which requires the
tank to be removed from the car via the boot(trunk). We had a look
at the car on their ramp and the very inaccesible feed hoses
connected to the tank look like they are corroded in position. Also
the drain plug is very hard to get at and even if it could be
released, would probably just dump the tank contents all over the
rear subframe creating a major fire hazard in the workshop! I am
going recommend they pump the tank dry via the filler nozzle. Then
disconnct the feed hoses at their connections to the filter
(shorter) and steel pipe (longer) and pull the tank with the hoses
still attached to it out of the car. Access to the pump is then
possible and changing it should be the straightfoward bit! Can
anyone give us any tips as the best way to go about this job?–
Clive Liverpool UK
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2

In reply to a message from Mad Moggie sent Sat 1 May 2010:

Not so. The fuel pump lives inside a plastic cannister that is
constantly full of fuel. The pump itself is good for 220 liters
per hour, and about half that amount is bled off inside the
cannister to power an eductor that keeps the cannister full. The
remaining fuel is sent to the fuel rail at the engine, where most
of it also returns to the cannister in the tank via the pressure
regulating valve at the front of the rail.
You can get a hand on the snap clips where the fuel delivery and
return lines attach to the tank above the differential. Feel
around and you will find the snap clips, then rotate the clip about
90 degrees and the hose will pull out of the fitting. It will
require some bit of pulling since there are two O-rings in each
fitting.
You can cut the two pipes near the filter and use compression
fittings (one 1/4 inch and one 5/16-inch) to remake them as I did,
but you will have to remove the left side shock absorber assembly
to get the still hoses re-routed through the body panels on
reassembly. Check my photo album for close up photos of the spring
clips.–
The original message included these comments:

Does anyone have recent experience of renewing the ‘‘in tank’’ fuel
pump on the XJ40? My car cut out when the fuel got low the other
day and I was told that the pump is probably on its way out,
especially as my car (a 1992 3.2) has done 143k miles. Apparently
the symptom is cutting out when fuel level gets down to about a
quarter of a tank and is too low to cover the pump and to cool it.
My local garage are nervous about doing the job which requires the
tank to be removed from the car via the boot(trunk). We had a look
at the car on their ramp and the very inaccesible feed hoses
connected to the tank look like they are corroded in position. Also
the drain plug is very hard to get at and even if it could be

–
Pete Peterson 70E(193K) 88XJ40s(253K & 242K) 94XJ40 (122K)
Severna Park, Maryland, United States
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3

In reply to a message from Mad Moggie sent Sat 1 May 2010:

Hi,
I replaced my in tank pump about 18 months ago.

I don’t think low fuel levels are giving the symptoms you
describe.

If you do need to change the pump it is a right mare if the
pipe connectors to the tank are really tight, but not so bad
once you have them off.

You only need to rotate the spring clips 90 degrees and
then just pull down on the ends IF they are not rusted on
like mine were.

I pumped the tank dry first.

Then drenched the connectors to the tank with freeing spray.

Then I made up a socket with a piece cut out the side so it
would push over the connector with the pipe located in the
cutout. I used this with a long extension and universal
joint to twist and rotate the connector until it came loose.
I had to drill a hole in the side of one socket and tack
weld a nut to it so I could clamp the socket to the
connector and pull it down and off.
None of this is easy due to the limited access and actual
view of what you need to see being blocked by the rear cage,
but it is not impossible.

I did all this work with the car on axle stands and me
lying on my back, with the car on a garage ramp it would be
a whole lot easier.

Once the tank is out and the large plastic top removed, I
removed the complete pump housing from inside by unclipping
the rubber mounts.

The housing the pump sits in is fastened together with a
plastic clip arrangement, the housing is brittle and easily
broken so be careful when prising it apart.

If you completely remove the spring clips holding the
connectors to the tank, make sure you refit them before
installing the tank. Leave them in the 90 degree position
and then just twist them into place from under the car when
you refit the pipes. So much easier than trying to feel if
they are in the right place afterwards.

good luck–
The original message included these comments:

Does anyone have recent experience of renewing the ‘‘in tank’’ fuel

–
Casso - 1993 4.0 Sovereign.
Liverpool, United Kingdom
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4

In reply to a message from Casso sent Sat 1 May 2010:

Thanks both to Peter in the US and Casso fellow Liverpudlian here
in UK for both of your long and helpful replies. To give a bit more
background, about 2 weeks ago the car stalled at a junction and I
was shocked to see the ‘‘petrol pump’’ low fuel symbol light up on
the VCM and I am pretty sure the gauge simultaneously dropped to
zero contents - actual contents just below one quarter. I sought
help on one of the UK Jaguar forums and was told ‘‘this has all the
hall marks of a failing fuel pump sadly…as the level falls the
pump is exposed and will run hot and fail…tends to fail with
about a quarter of a tank or 150 miles on the VCM range.’’ I
therefore decided to get a new pump fitted. I was warned it was
a ‘‘nightmare of a job’’ especially if the old fuel lines are
corroded and their unions rusted solidly onto the tank which I am
pretty sure is the case on my car. (But I was also advised to first
check the electrical multiplug on the tank for corrosion.) Parts
are a problem. I have a new pump and new internal rubber hoses. But
the fuel feed hoses are unobtainable new in the UK as far as I can
establish. So I am now aiming to obtain secondhand ones (already
have one) as patterns for new hoses to be made professionally.
Doing the job by cutting and scrapping the old fuel line hoses was
recommended to me on the other forum as the unions on the tank
would most likely be impossible to release due to rust. So pumping
out the tank and ensuring I have those two new fuel line hoses
seems to be the way to go. The job will be done by a local garage
so I need to make sure the car goes in for the job with all new
parts that might be needed.–
Clive Liverpool UK
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5

In reply to a message from Mad Moggie sent Sun 2 May 2010:

Clive,

I’m a little doubtful at the prognosis you have been
offered. It was true that in the early cars with the
external fuel pump, there were problems of the pump
overheating and ‘cavitating’ when the fuel level was low.
Often, the solution was to wait a few minutes and it would
start pumping OK again and adding fuel very often cured the
problem until the next time the car operated in high ambient
temperatures and the fuel level dropped - but we are talking
here about Death Valley type temperatures, not the ones you
meet in Merseyside!

Does the fuel pump not work at all now? If it does, have you
measured the fuel pressure at the rail?

Before removing the tank to replace the fuel pump, I would
want to be very certain that the pump has failed.

If you jump the fuel pump relay, does the pump run continuously?

BTW, what do you mean ‘‘was shocked to see the ‘petrol pump’
low fuel symbol light up on the VCM’’? The low fuel indicator
is on the dash display, not the VCM - do you mean a ‘Fuel
Fail’ warning on the VCM?–
Bryan N, '91 Sovereign 4.0 L, RHD
Cambridgeshire, United Kingdom
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6

In reply to a message from Mad Moggie sent Sat 1 May 2010:

Clive,
I would agree with Bryan that it is unlikely for the pump to
fail in such a way.
I went through the job of replacing mine about a year ago
and the old one turned out to be fine.
My car is a 92 and from your description sounds like the
same set-up.
I managed to do the whole job on the drive with no lift or
any special tools.
The car was jacked up at the back with the wheels still on,
then lowered onto hefty wood 10 inch blocks with stops to
prevent the car rolling.
The pipes can be removed by hand, just a matter of twisting
your arm up and around a bit, the diff does not need to be
lowered and the prop shaft was left in place. Remember I
managed this laying on my back mainly by feel alone so a
garage should have no problems.
There was NO corrosion of the joints. The unions just pull
out right below the tank when the clips are removed.
(Yes I know everyone says just turn them 90 but to be sure
there out, pull them right off, it is easy to put them back
onto the unions at the 90 deg position for re-installation
through the hole in the boot prior to re-installing the
tank. !don’t forget!.)
I would doubt there will be any corrosion on yours, they are
made of some alloy, and the tank is zinc plated, the contact
with each other is just two (on each) rubber ‘o’ rings. (I
got new from a dealer for about �3). One fitting is larger
diameter than the other so they cant get mixed up.
Fuel needs to be as low as possible but not empty as the
internal pipes go up to the top of the pump, nothing can
come out when the two bottom unions are removed, (except
what’s in the pipes so maybe drain at the filter first.) so
forget the drain plug.
Drop the car and remove everything from the boot. Remove the
straps and move the filler rubber boot down the pipe…
Pull the whole tank toward the back with the filler side
dropped a little and the whole thing tilted toward you so
the bottom union bosses clear their hole.
It will come out honest!. It can be stuck to it’s rubber mat
below, but with a bit of patience and a helping hand it’s
not too bad.
Take out the level sensor and remove the evaporative loss
flange. This is where my problem was but I would have had
to take the tank out anyway so no real loss.
The flange has a connector on the outside but also one
inside and the pins had just burnt away, so I sealed that,
drilled and inserted two brass studs for new connections,
then replace the pump anyway.
It’s tricky, and possibly a bit dangerous, but with common
sense !no smoking! :slight_smile: not too bad.
I made a brass screwdriver to undo the two ‘jubilee’ clips
on the internal pipes at the top of the pump. Then plunging
my hand into the fuel ‘Should wear gloves that don’t
dissolve in petrol!’, unhook the rubber mounting from the
tank and remove the whole cartridge. I only bought the inner
pump itself, so just unclipped the lid pull out the old pump
and put in the new. I made up new cables, a bit longer, so
it would be easier to connect with eyelets to my new brass
studs.
And as they say replacement is the reverse of removal. Just
don’t forget the clips and having a small child to climb in
the boot helps a lot. :).

If you still decide not to do it yourself maybe this will
help the garage.

Cheers.

Steve.
Leicester UK.–
Steven Martin
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7

In reply to a message from Steven Martin sent Mon 3 May 2010:

…I have a fuel pump problem, it overheats in the summmer and the
engine cuts out…I think I have an external fuel pump…I have an
89 3.6 sov for parts, but I dont know if it has an external fuel
pump too that I can put on my 87 2.9???–
XJ6 2.9 87’ RHD 88 3.6 sov.89 3.6 sov. WV beatle 77, 69.
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8

In reply to a message from Ice9785 sent Mon 3 May 2010:

Yes, the '89 3.6 has an external pump too. They fitted the
in-tank pump from '91 MY on.–
The original message included these comments:

…I have a fuel pump problem, it overheats in the summmer and the
engine cuts out…I think I have an external fuel pump…I have an
89 3.6 sov for parts, but I dont know if it has an external fuel
pump too that I can put on my 87 2.9???

–
Bryan N, '91 Sovereign 4.0 L, RHD
Cambridgeshire, United Kingdom
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9

In reply to a message from Ice9785 sent Mon 3 May 2010:

Thanks to Steve and Bryan and also for the member who was suffering
similar pump failure in summer (but possibly with an external pump.)
The voting does seem to indicate that this is not a typical ‘‘pump
failure scenario’’ - do they usually just die compeletely maybe?
Sorry Bryan, what I meant was that the ‘‘petrol pump’’ symbol lit up
on the left hand instrument display. I had never ever seen this
come on before (other than on the start up systems check),never
having risked running the car low on fuel. The car runs very well
indeed otherwise and it only ever cut out on this one occasion with
these symptoms(but as I was just about to enter the Mersey Tunnel
at the time it gave me a very nasty scare!) The diagnosis is based
on pretty categorical advice from a main contributor to the Jaguar
Enthusists’ Club XJ40 forum i.e. basically it had all the hallmarks
of a failing pump ‘‘and would only get worse.’’ (If you are also a
member of JEC mine is the latest thread on their XJ BB under ‘‘Fuel
system’’.) I suppose the fact that I now have a brand new pump,
hoses etc. all ready to go onto the car makes me want to get the
job done, though my local garage are still not relishing doing the
job. But checking the fuel rail pressure sounds interesting -
would it reveal a pump ‘‘on its way out’’ by a low reading maybe?
The guy on the JEC board did also recommend checking the tank
multiplug. I suppose if this failed intermittently, the pump would
die and the gauge also drop to zero, also triggering the low fuel
icon. Any more ideas on this one most welcome.–
Clive Liverpool UK
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10

In reply to a message from Mad Moggie sent Mon 3 May 2010:

Clive,

I think you are being slightly mislead here. There is no
connection between the electrics for the in-tank fuel pump
and those for the in-tank fuel contents sender unit. They
operate completely independently, so if you saw the ‘fuel
low’ warning on the dash at the same time as the engine
died, it was either a big coincidence (if the cause was a
failing fuel pump) or the engine died because you were out
of fuel! :wink:

If you know that the tank has plenty of fuel, ignore the
fuel sender unit / dash indication for a while and
concentrate on checking the fuel pump circuit.

Find the fuel pump relay, remove it and jump pins 30
(Brown/black wire) & 87 (Blue/red wire). The pump should run
continuously. If it doesn’t run, trace the connection up to
the evaporative loss flange atop the fuel tank (Blue/red &
Black wires) and put 12 volts directly on to those
terminals. If the pump doesn’t run then, the problem is
either as Steve described (a wiring failure inside the
flange or the tank - not uncommon) or the pump itself is
duff. Either way, you can then happily remove the tank as
Steve described to fix it.

While you are doing that, you can replace the sender unit -
you will need p/n LNE2000AC and a new sealing ring ARA1502J.

BTW, if the fuel pump is still working and you still want to
drain some fuel out of the tank (which you may need to do
anyway to replace the sender unit with the tank in-situ) you
can disconnect the fuel feed line from the back of the fuel
rail, attach a length of (I use garden) hose to the line and
then jump the fuel pump relay as described to run the pump
continuously to dispense the fuel in to a suitable container
(or another car).–
The original message included these comments:

The voting does seem to indicate that this is not a typical ‘‘pump
failure scenario’’ - do they usually just die compeletely maybe?
Sorry Bryan, what I meant was that the ‘‘petrol pump’’ symbol lit up
on the left hand instrument display. I had never ever seen this
come on before (other than on the start up systems check),never
having risked running the car low on fuel. The car runs very well
indeed otherwise and it only ever cut out on this one occasion with

–
Bryan N, '91 Sovereign 4.0 L, RHD
Cambridgeshire, United Kingdom
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11

In reply to a message from Bryan N sent Mon 3 May 2010:

Hello again Bryan and very grateful for your input and time. I am
thinking ‘‘electrical problem’’ here myself. Specifically I was
advised (by the other forum member) to check the ‘’ large black plug
in the loom about 18 inches from the tank, this is the connector
that allows the loom to be split for taking the tank out, pull this
apart and check for burning on the connections’’. I thought maybe
that this multiplug might hold the individual connectors for both
the pump and sender and maybe their common earth,a bad connection
therefore knocking them both off line momentarily. There were
approximately 40 litres left in the tank when she cut out. I know
this because I immediately stopped at a station and it took 50
litres to refill the tank. (XJ40 tank = 89litres.) I am considering
replacing any fuel system relays as you suggest once I establish
their locations and types - easy job. The car is running very well
indeed at present, as it has always done. What are the usual
symptoms of an expiring pump? Do they just fail suddenly and
completely or do you get poor running and a gradual deterioration
in performance? (No such symptoms at all here yet.)–
Clive Liverpool UK
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12

In reply to a message from Mad Moggie sent Mon 3 May 2010:

The symptoms a failing pump vary - but usually they just
stop or start to get very noisy in operation.

Nine times out of ten, the problem is the fuel pump circuit,
a failed relay or, in a number of cases, failure of that
wiring in the evaporative loss flange - the wires actually
burn out because they can’t take the current required to run
a worn pump. Jaguar refused to sell a single pump and
insisted on supplying the complete pump + pump module +
evaporative loss flange and wiring as a complete assembly to
overcome this wiring problem.

Sometimes the problem is simpler than that - needing simple
cleaning of the contacts on the evaporative loss flange
connector.

You need to check it electrically before condemning the pump
itself.

You should find the fuel pump relay in a yellow base on a
bracket in the left rear corner of the engine bay just aft
of the back end of the coolant expansion tank.

BTW, I can’t see any connector which houses both the fuel
contents sender wiring and the fuel pump wiring. Perhaps
your informant would identify which connector they mean. The
only connector in the trunk which serves the fuel pump is a
2-way Black connector near to (but not connected to) the
fuel tank sender unit.–
The original message included these comments:

Hello again Bryan and very grateful for your input and time. I am
thinking ‘‘electrical problem’’ here myself. Specifically I was
advised (by the other forum member) to check the ‘’ large black plug
in the loom about 18 inches from the tank, this is the connector
that allows the loom to be split for taking the tank out, pull this
apart and check for burning on the connections’'. I thought maybe
that this multiplug might hold the individual connectors for both
the pump and sender and maybe their common earth,a bad connection
therefore knocking them both off line momentarily. There were

–
Bryan N, '91 Sovereign 4.0 L, RHD
Cambridgeshire, United Kingdom
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13

In reply to a message from Bryan N sent Mon 3 May 2010:

Hello again Bryan,
What I will do for the time being is to just replace fuel pump
relay in the engine bay. I would ideally like to check the
evaporative loss flange connector also. And I note that Steve
Martin says above that ‘’…the evaporative loss flange. This is
where my problem was but I would have had to take the tank out
anyway so no real loss.’’ My problem is that there is no way that I
can get the tank out myself and if it has to come out for the
evaporative loss flange connector to be checked,(assuming there is
no access to it at all even externally with the tank in situ) it
might then be sensible to put in the new pump. The pump certainly
sounds OK and the car runs fine so relay renewal is all I will be
doing for now. But one last question - would checking the fuel
rail pressure give an indication as to the pump’s health? If it
were found to be below par, this would tip the balance in getting
it changed.
Thank you,
Clive.–
Clive Liverpool UK
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14

In reply to a message from Mad Moggie sent Tue 4 May 2010:

Clive,

Do you have a Haynes Manual for the car?

If so, look at Chapter 4, Section 3 and the Specifications
section at the beginning of that chapter for the fuel
pressure readings you should get. Of course, out-of-spec
fuel pressures can be caused by things other than a poorly
performing pump - e.g a failing fuel pressure regulator.

However, to do that you will need a fuel pressure test rig
similar to this one :-

http://www.jag-lovers.org/snaps/snap_view.php3?id=1076076938

Note the fuel rail / fuel line connections are M14 x 1.5mm

All of this talk of fuel pressure being the cause of your
engine stalling (on just one single occasion???) could of
course be a complete ‘red herring’.

It is known that a failing crankshaft position sensor (CPS)
for example can cause that to happen - no spark, no fuel
injectors and no VCM fault codes.

I think you will have to wait until it happens again to be
able to pinpoint the likely cause - and I wouldn’t pull the
tank out just yet!–
The original message included these comments:

doing for now. But one last question - would checking the fuel
rail pressure give an indication as to the pump’s health? If it
were found to be below par, this would tip the balance in getting
it changed.

–
Bryan N, '91 Sovereign 4.0 L, RHD
Cambridgeshire, United Kingdom
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15

In reply to a message from Ice9785 sent Mon 3 May 2010:

I had the stalling in hot weather problem with my 88 as well. I
discovered that I could simply loosen the filler cap, restart, and
keep on down the road. There is supposed to be a bit of air
circulation through the tank, pulled by intake manifold vacuum
through a thermal valve near the temperature sender, then through a
carbon canister from the tank. There are two small hoses poking
through the bulkhead behind the differential that let air into the
system. If they’re clogged (often) they won’t let air in and cause
the fuel to flash to vapor at the inlet to the pump.
Loosening the filler ensures adequate atmospheric pressure in the
tank which prevents fuel from flashing to vapor under a partial
vacuum situation. Try it next time she stalls in hot weather.–
The original message included these comments:

…I have a fuel pump problem, it overheats in the summmer and the
engine cuts out…I think I have an external fuel pump…I have an
89 3.6 sov for parts, but I dont know if it has an external fuel
pump too that I can put on my 87 2.9???

–
Pete Peterson 70E(193K) 88XJ40s(253K & 242K) 94XJ40 (122K)
Severna Park, Maryland, United States
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16

In reply to a message from Mad Moggie sent Tue 4 May 2010:

Hi Clive,
My pump failed without any warning whatsoever.

No bad running symptoms from the car, and no increase in
noise level from the pump. The car just failed to start one
morning.
By following Bryans process of tracing right back to the
pump connections, and then applying 12 volts directly to the
terminals, it confirmed the fault was inside, and the tank
needed to be removed to go any further.

Working backwards from the tank, the first plug connector
you come to is very suspect, and as it is easy to check I
would look here first. I know of several cars where this has
overheated and the internal spades have blackened making a
poor intermittent contact. You do not need to remove the
tank to access this or the evaporative loss flange
terminals, only if you need to remove the flange from the
tank completely. If the pump doesn’t run with 12 volts
directly to the terminals located within the flange then
only then will it need to be removed. It could save you time
starting here.

This was also the case with my car. Not long after I first
bought it five years ago it began stalling occasionally and
then refused to start completely. When I traced the fault I
chopped that plug out of the system and made my own.
It was at least 50,000 miles later when the pump actually
failed so I don’t think it was a failing pump drawing extra
current that caused this plug connector to fail.

When I finally managed to get the pipe connectors off the
tank, the inside of both connectors were like brand new, all
the corrosion is on the outside and will brush off easily
with a wire brush.

The ’ low fuel ’ petrol pump symbol will sometimes appear
on my car when I have at least a quarter tank.
It can remain lit for around a minute or so with the gauge
reading in the red sector if I have had to brake hard for
instance, or if I park with two wheels on a pavement. It
always corrects itself and reads steadily afterwards, it has
always been like this during my ownership.

There can be lots of reasons for the engine to stall at a
junction, I think the misleading info you have received
regarding the fuel pump/ low fuel, has not helped at all,
and may even have you looking in the wrong place.

A fuel pressure test may certainly be helpful in diagnosing
what caused the cut out, but it will not prove conclusively
how much service life is left in the pump.

good luck,–
The original message included these comments:

evaporative loss flange connector also. And I note that Steve
no access to it at all even externally with the tank in situ) it
might then be sensible to put in the new pump. The pump certainly

–
Casso - 1993 4.0 Sovereign.
Liverpool, United Kingdom
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17

In reply to a message from Casso sent Tue 4 May 2010:

Thank you all for the advice. You may well be right that it was
a ‘‘red herring’’ single event unrelated to the injection system. But
I will be checking the fuel pressure as a precaution and have just
bought a full test set with a large range both metric and SAE
fittings from a US tool fiim on Ebay (�86.) A good investment as
the Jag is not my only injected car. Thanks for telling me the size
of the connector, though, and yes I do have the Haynes manual. Pete
Peterson’s advice re. tank vacuum build up is worth checking as I
had another make of car some year ago with this problem. And Casso
must be describing that ‘‘big multiplug onto the loom’’ that the JEC
forum guy recommnded I check. So before all the trim and boot panel
goes back I will check that out. The tank can stay put for now and
fingers crossed it was just a one off. But I will still carry out
the checks above.
Thank you all for your inputs and your time - great to receive such
an excellent response from forum members!
Clive.–
Clive Liverpool UK
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18

I have a 1994 XJ40 4.0(USA) all I can find on it is there is a fuel pump relay in the trunk near the rear tail light/power antenna…but i haven’t found it yet ;( HELP!!!

19

Gary - here is a diagram and the source:

Screenshot_20210414-185711
Screenshot_20210414-1857111440×2560 183 KB

Screenshot_20210414-185535
Screenshot_20210414-1855351440×2560 297 KB

To access you need to remove, from.inside the trunk, the cover over the right tail light assembly (two plastic thumb wheels) then pull the right side trunk finish panel away from the side of the trunk near the tail light to reveal the relay.

20

On my 94 it’s part of a module of 4 relays, and yes it’s where Mike said it is, but a bit close to the antenna than the tail light.
Worth checking the o2 sensor heater relay on the firewall too.