[xj-s] Engine bucks, eventually will stop XJS 1988

Had an interetsing experience on a long drive, hope somebody can
help with this newly aquired car.

It would start bucking driving down the road,under a steady pedal,
and increasing with even a slight increase in pedal pressure.
I found that if I slowed down to a very low speed, the fuel pump
was making a loud whining noise, each and every time this occurred.

If I shut the engine off, and restarted,the pump was quiet and
power was back to normal-every time.If I just kept going without
shutting off the engine , it would eventually die, with no response
to the gas pedal.

With the noise, and the restarting, it appears safe to assume there
is an issue with fuel system, maybe with the pump itself.
I don’t even have a manual yet, as this experience was as I was
driving it for the first time.

Any help you can provide with checking the fule intake filter sock
(along with how do I get at it-am crossing my fingers I don’t have
to drop the tank)as well as any ideas and facts like fule pressure
readings(it’s an injection system) Would be GREATLY appreciated.

I checked to see if my plug wires were bad, just to be on the safe
side, on this lucas sytem, have little else I can check at this
point.
Where can I get a good service manual?
Thanks!–
Never thought this would happen…
atlanta GA, United States
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In reply to a message from Georgia Jag sent Sun 22 Apr 2007:

Hi,

Being as your car is an 88, it has an external fuel pump, next to
the battery, under the tin shield arrangement. Under the battery
carrier is a small sump fuel tank. This is fed with fuel by gravity
from the main tank higher up. The pipe from the top of this tank
goes to the top of the fuel pump, and on the other end of this pipe
arrangement, INSIDE the sump tank is a suction filter, which is
known to clog up, and cause supply problems to the pump, which in
turn causes fuel supply issues to the EFI system. When the pump
gets starved for fuel it gets noisy??.

This filter can be removed by simply emptying the main tank,
draining the sump tank through the bung in the floor, and tapping
(brass punch) the lock ring anti-clockwise, remove the set up and
clear/replace the filter. BE CAREFULL PLEASE AS A SPARK HERE WILL
MORE THAN SINGE YOUR EYEBROWS, AND UPSET THE KITTY. Take ALL the
required (and then some) precautions.

Another less common thing to cause supply issues to the pump is a
fuel tank that is NOT breathing. Try driving it with the fuel cap
removed (not too much fuel onboard), and see what happens.

The fact that it starts right up after stopping leads me to go to
these 2 things before re-inventing the wheel (as we say).

Grant Francis–
The original message included these comments:

I found that if I slowed down to a very low speed, the fuel pump
was making a loud whining noise, each and every time this occurred.
If I shut the engine off, and restarted,the pump was quiet and
power was back to normal-every time.If I just kept going without


85 XJSV12 (The Badcat).76S2XJ12 (her cat)87XJ40 3.6
Adelaide South Austarlia, Australia
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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With the noise, and the restarting, it appears safe to assume there
is an issue with fuel system, maybe with the pump itself.
I don’t even have a manual yet, as this experience was as I was
driving it for the first time.

Any help you can provide with checking the fule intake filter sock
(along with how do I get at it-am crossing my fingers I don’t have
to drop the tank)as well as any ideas and facts like fule pressure
readings(it’s an injection system) Would be GREATLY appreciated.

I checked to see if my plug wires were bad, just to be on the safe
side, on this lucas sytem, have little else I can check at this
point.
Where can I get a good service manual?
Thanks!----------------------------------------------------------------------------------------------

You get at the fuel strainer, it is only a strainer and not a true
filter, by taking off the battery cover and the cover below that.
There you find the surge tank with a large cover and a pipe coming out
of the cover for supplying the fuel pump.
The strainer is on the other side of that cover.

Your best bet is to download Kirby palm’s book about the XJ-S from the
Jag-lovers website.
That tells you how to pinch of the fuel from the main tank and drain
the surge tank.
One day you need to do this anyway, takes 2 or 3 hours by finishing time.

The fuel pumps do eventually give up anyway, if in doubt replace - not
too expensive.

Richard Dowling, Melbourne, Australia: 1979 XJ-S; 1985 XJ6; 1988
XJ-S V12 convertible

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In reply to a message from Richard Dowling sent Sun 22 Apr 2007:

Very very helpful , Thank you both!–
Never thought this would happen…
atlanta GA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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