1989 XJS Cold Weather Gremlins
#1
12-30-2009, 07:55 PM
Guest
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1989 XJS Cold Weather Gremlins
I own an immaculate 1989 XJS. I'm the second owner, it has 50k miles, and has been dealer maintained since new. I love looking at the car, but it has a gremlin that is bothering me enough that I'm ready to sell the car. If anyone has the solution, I'm ready to hear it. I do all the work on all my cars, and this car is the one that drives me the most insane.
I've been trying to use this car as my winter car. When the temp is above 10F, it drives great. Once the temp drops below that, the gremlins come out. After the car starts, I will drive, and the engine will suddenly lose power. It will be running, but when I floor it, I only get 1500 RPM. Then the power will come back, and it will run fine. This power loss and recovery cycle will happen every few minutes. The car will then run fine for a few minutes before the engine suddenly completely dies. After the car dies, it won't start. After I've started cussing about having to walk in the subzero temperature, the car finally starts. After it restarts, it runs fantastic.
Does the XJS typically have low temp problems? If not, what on earth can be causing the problem?
Since the problem is intermittent, I can't get any instrumentation on the car to figure out what is going on.
I've been trying to use this car as my winter car. When the temp is above 10F, it drives great. Once the temp drops below that, the gremlins come out. After the car starts, I will drive, and the engine will suddenly lose power. It will be running, but when I floor it, I only get 1500 RPM. Then the power will come back, and it will run fine. This power loss and recovery cycle will happen every few minutes. The car will then run fine for a few minutes before the engine suddenly completely dies. After the car dies, it won't start. After I've started cussing about having to walk in the subzero temperature, the car finally starts. After it restarts, it runs fantastic.
Does the XJS typically have low temp problems? If not, what on earth can be causing the problem?
Since the problem is intermittent, I can't get any instrumentation on the car to figure out what is going on.
#2
01-03-2010, 12:51 AM
Mine had suffered with a nearly identical set of problems, as you note impossible to troubleshoot because of the intermittant nature.
It was a crap shoot on whether the car would run perfectly, or act like one bank of 6 cylinders was running, or if it would just drop you at the side of the road and never start again....Until you let it sit, call the tow truck and he shows up....and then it would start.
I do not have the extreme temperature component as affects yours, but mine may have been somewhat temp related also.
But I'll cut to the chase. After months of searching, it turned out to be the blasted main brain--the ECU that lives in the trunk (boot). Replaced it with one from JaguarHeaven, and the problems went away, never to return.
From the sounds of your problems, it might just be the ECU. Hope this helps.
Lou
It was a crap shoot on whether the car would run perfectly, or act like one bank of 6 cylinders was running, or if it would just drop you at the side of the road and never start again....Until you let it sit, call the tow truck and he shows up....and then it would start.
I do not have the extreme temperature component as affects yours, but mine may have been somewhat temp related also.
But I'll cut to the chase. After months of searching, it turned out to be the blasted main brain--the ECU that lives in the trunk (boot). Replaced it with one from JaguarHeaven, and the problems went away, never to return.
From the sounds of your problems, it might just be the ECU. Hope this helps.
Lou
#4
01-03-2010, 11:43 AM
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Its the norm on any car (or dishwasher, or computer, or anything) if fighting an intermittent problem. The only other choice is to hope the problem gets worse and/or more frequent so that a decent diagnosis can be performed.
My tolerance for guesswork is usually dictated by my pocketbook. A $25 or $50 guess is one thing. A $250 or $500 guess is another :-)
Cheers
DD
#5
01-09-2010, 01:36 PM
I've been thinking about your set of symptoms, and they sure do sound electric / electronic in nature. Especially the parts about intermittant cessation and returning to normal, just like mine did, with no seeming rhyme nor reason to it.
Maybe someone on this board has an extra ECU lying around you could try...?
Maybe someone on this board has an extra ECU lying around you could try...?
#6
04-26-2014, 02:05 PM
Member
Sorry to bring up an old thread!
Have been reading the entire site and love it! May help another owner. In 2000, I had a 82 xjs. It would always start, but would die at random! At times, wouldn't start at all! I had no internet, but had a Hemmings, and called a guy who advertised jag knowledge. He said " Its the tps, jag updated it, you need a new retrofit". Did it, and never had a problem again! Took the old one apart, and it had carbon everywhere! Worn thru tracks too! Check your tps, as well as the other recommendations! Hope this helps someone.
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