Hi all, I am trying this group as I have NO IDEA where to start. I have a
1986 XJS 12cyl. Problem: Car starts, but then dies when I let go of key,
sometimes it runs for a while, sometimes she will not run at all. When she
does decide to take a ride on 1/5 throttle she bucks like a bronce, a bit
more on the gas and she seems fine, until about 4/5 throttle when she will
die out completely. I actually have to drive it at 2500rpms in the rare
instance that she runs at all. Any pointers will be greatly appreciated. I
have not really check anything at this point. New purchase, so I do not
have much history other than a "cheap and good" mechanic worked on her.
Thanks to all.
Pepe - 16 Oct 2004 13:36 GMT
Make sure she get plenty to drink!
There seams to be blocked filters
for the petrol/gasoline. Also make
sure all fuel injectors are clean.
Pepe
> Hi all, I am trying this group as I have NO IDEA where to start. I have
> a 1986 XJS 12cyl. Problem: Car starts, but then dies when I let go of
[quoted text clipped - 7 lines]
> mechanic worked on her.
> Thanks to all.
Stuart Adair - 16 Oct 2004 14:26 GMT
Peter,
Sound to me like a classic Auxiliary Air Valve problem. This valve is
located on the rear of the left hand bank of cylinders when viewed from the
drivers seat. I will send a picture down to your email address to help.
The valve controls the idling functions and acts a bit like a choke. They
are always getting clogged up and need clearing.
I did sort mine out by soaking it in WD40 and then boiling it in water until
the valve cleared itself - But I suggest you make sure your wife is out when
you do this !!!
Best of luck
Stu
> Hi all, I am trying this group as I have NO IDEA where to start. I have
> a 1986 XJS 12cyl. Problem: Car starts, but then dies when I let go of
[quoted text clipped - 7 lines]
> mechanic worked on her.
> Thanks to all.
PeteR - 16 Oct 2004 18:55 GMT
Ok. The saga continues. I traced it to the fuel pump not working
correctly, and removing and replacing the fuel pump relay fixed the no run
situation. then I took it for a ride and the transmission seemed to resist
shifting into high gear. Boy am I starting to get cranky. Also, I noticed
that the vacuum advance nipple doesnt have a vacuum hose attatched to it at
all. Is this car supposed to have a maechanical advance? Or is it
electronic?? Any help on a transmission suggestion??
Sigh.
Thanks to all
Peter
> Peter,
>
[quoted text clipped - 23 lines]
>> mechanic worked on her.
>> Thanks to all.
PeteR - 16 Oct 2004 20:59 GMT
Wow. Found the transmission problem. It was the kickdown switch. I
disconnected a wire from the switch and my tranny was as good as before. I
do not know if the switch just failed or I unintentionally moved it a bit,
but that was an easy fix! I am destined to replace the two relays for the
fuel pump, as they are acting up again. Thank you all who replied, and I am
cleaning the aux air unit tomorrow for good measure.
> Ok. The saga continues. I traced it to the fuel pump not working
> correctly, and removing and replacing the fuel pump relay fixed the no run
[quoted text clipped - 34 lines]
>>> and good" mechanic worked on her.
>>> Thanks to all.
Stuart Adair - 17 Oct 2004 13:09 GMT
Peter,
Glad to hear that things are running a little better. My V12 is a 1987 model
and does have a vacuum advance fitted to the distributor.
Stu
> Ok. The saga continues. I traced it to the fuel pump not working
> correctly, and removing and replacing the fuel pump relay fixed the no run
[quoted text clipped - 34 lines]
>>> and good" mechanic worked on her.
>>> Thanks to all.
PeteR - 17 Oct 2004 22:09 GMT
I am sure that there SHOULD be one there. I have been busy removing wires
and strange gizmos from this car. For a 12 cylinder it sure doesnt move
quickly. But then again my previous wheels was a Corvette,,, Hey, by the
way... on the throttle cable at the kickdown switch area is the cable that
has an hourglass sort of shape,. This is where the micro switch gets turned
on during a kickdown. When I looked closely at my throttle cable I noticed
a small threaded hole on the hourglass casting. I assue it should have a
screw in it, and I assume that it should attatch or limit something. Does
anyone have any ideas? Thanks again for all the help.
> Peter,
>
[quoted text clipped - 41 lines]
>>>> and good" mechanic worked on her.
>>>> Thanks to all.
T.G. Lambach - 17 Oct 2004 00:59 GMT
The symptoms that you describe are those of fuel starvation. The
possible causes are weak fuel pump, clogged fuel filter or malfunction
within the fuel injection system itself.
Given the car's age I suggest you test the fuel pump's pressure and
output volume. A "tired" pump is the likely cause.
V-12 experts may have a more concise suggestion.
PeteR - 17 Oct 2004 22:11 GMT
A new filter, and pump are in the mail. I will let all know of my
successes.... or failures.
> The symptoms that you describe are those of fuel starvation. The possible
> causes are weak fuel pump, clogged fuel filter or malfunction within the
[quoted text clipped - 4 lines]
>
> V-12 experts may have a more concise suggestion.
Stuart Adair - 18 Oct 2004 09:22 GMT
Peter,
The vacuum advance pipe goes to the right hand bank of cylinders (Viewed
from the drivers seat). It goes between the castings of the inlet manifold
and underneath somewhere !!!
On my car the pipe is black with a white stripe but knowing Jaguar parts
that could be different on every car they made.
I'm going to send you some pictures that might help.
Stuart
>A new filter, and pump are in the mail. I will let all know of my
>successes.... or failures.
[quoted text clipped - 6 lines]
>>
>> V-12 experts may have a more concise suggestion.
Nick - 22 Oct 2004 08:05 GMT
Please check the coolant temp sensor is not reading erratically either. This
is CRITICAL to the fuel supply. Wires perished can also cause many
headaches - especially on a V12- intermittent open circuits, short circuits,
high resistance etc.
COLD = 9000K Ohm (from memory.... i think it is in specs)
HOT op temp = 200 Ohm.
HTH
Nick.
> Hi all, I am trying this group as I have NO IDEA where to start. I have
> a 1986 XJS 12cyl. Problem: Car starts, but then dies when I let go of
[quoted text clipped - 7 lines]
> mechanic worked on her.
> Thanks to all.