Hello out there need some help I have 1983 jag XJS 5.3 v12 THE ENGINE RUNS GREAT ...WHEN IT RUNS! I have had this car since march 07 bought it for my wife's b'day it's in pretty good shape all around except for this starting issue it runs when it wants to and sometimes it will run all day and then just dies out and wont start again until it wants to ,I had it at jaguar of Exeter N.H. and they had it for until the end of may I paid 1300.00 in parts and labor they changed the potentiometer,throttle rod and bushings but to no avail that didn't do the trick i just traced the fuel system everything seems ok it looked like it was the pickup module changed that this weekend another 100.00 and my labor i have both fuel and spark but it still wont run I really love this car and want desperately to fix this engine because when it does run it you can barely hear it, it runs so nice but,my patience are wearing thin and i have a gm 350 crate engine with a rv cam and 27,000 miles on it that is just begging me to rip the 5.3 out and put her in but id really rather not only has 74,000 miles on it!!!!
please anybody have any experiences like this NEED HELP !!!!! i SAW ART DICKENSONS ON THIS SITE SOME WHERE FROM PACIFIC JAGUAR MINE IS THE SAME ONLY SEBRING RED WITH SADDLE INT PLEASE ANYBODY help!!!! b-4 I do the inevitable and rob it of it;s originality!!! HELP!!!!!!
Bill Paradise
1990 XJ6
1983 XJS

Submitted by jamescolliprie… on Mon, 06/18/2007 - 14:56

Rereading a portion of Kirby Palm's Help for the Jaguar XJ-S Owner (INJECTION SIGNAL FAILURE about page 304) reminded me that there are two failure modes for that coaxial cable. The second mode is a short between the inner core wire and the shield braid. Either mode can cause both intermittent or continuous problems.

Jim Collipriest
El Dorado Hills, CA
1989 XJ-S

Submitted by jamescolliprie… on Sat, 06/16/2007 - 18:29

Hi William,

I just posted a Reply to Henry, (next item posted after yours). His problem sounds similar to yours.

Based on the fact that your problem is intermittent, I would bet that you have a broken lead from the ignition amplifier to the EFI ECU. Check the discussion in Kirby Palm's book on XJ-Ss regarding problems with this wire.
Hopefully, you won't have to swap engines. The V-12 is a sweet thing when running properly.

Jim Collipriest
El Dorado Hills, CA
1989 XJ-S