88 xjs v12 wont start when cold
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88 xjs v12 wont start when cold
I just got a 1988 XJS V12 with 73K miles. It was very hard to start when cold then seemed to start fine when warm. When I tried to test drive it died and didn't start until the next day. I then changed the plugs and wires. It won't start at all now but it acts like before when cranking. It spits and acts like it want to run but just won't quit take off, the wires are correct. Another thing I did notice the other night before I changed the plugs was the cat was turning cherry red at first then went away after awhile. It has spark and will jump over 1/2" gap, has fuel pressure past the regulators but I don't know how much, seems OK. I pulled a injector and it is pulsing fuel. Any ideas? I haven't done a compression check yet. thanks.
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Joined: Apr 2010
Posts: 145
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From: Virginia
Hi Jon, congrats on the XJS. I also have an '88 and like it better than the newer one we have. By your description I would start looking for some vacuum leaks. I say this because on a speed density system like these cars have, a large vacuum leak will cause the ecu to think there is low vacuum, hence heavy load condition. It will then dump fuel. That could be why your cat was glowing red. Or perhaps you have an early Marelli system and are in the middle of having a Marelli meltdown. Check for the XJS help book by Kirby Palm. I will explain what to do if you have the Marelli. I have found the V12 to be quite gratifying to work with. Not necessarily easy but definitely responsive to maintenance. I had many things to straighten out on our Lucas system, even though it seemed to run fine at the time. Much better now though! 
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