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Discussion Starter · #1 ·
1991 YJ 6 cylinder,
( i know im in the wrong area but i posted in the YJ fourm too and no responce yet but need help just wondering if this has happened to anyone in a tj also.. running out of ideas)

when i go to start the jeep*(the jeep would crank not start)*
when i would turn the key the maintenance light would come on,
but the check engine would not,
i some how figured out that if i left the key turned on for a while the check engine light would eventually flicker on and when it was a solid light, the jeep would start perfectly and run fine.
i could turn the jeep off and turn it back on with no problem, all day long but it would happen again if it sat for a while (hours) or over night.
when it was cold outside,it would take longer for the check engine light to come on.
hence taking the jeep longer to start.
All of a sudden, neither light comes on and the jeep wont start no matter how long i leave the key turned to the on position.

i have down different things to check problem, (plugs, plug wires, starter solenoid,checked fuses.)

now im stuck...

(someone told that the fuel pump might not be grounded, They also said the ground wire is behind the E Brake. or Brake release but i cant find it, if anyone had a picture of that spot, that may help me..)

any help would be great.. :confused::banghead:
Thank you.
-Vernon
 

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Discussion Starter · #3 ·
If you can swap PCM from another Jeep, I would do that to see if yours is going out.
dont know alot about that, what would it do and is it difficult?
 

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You may need to pull your distributor cap off and check the terminals for corrosion. I had a similar problem with it cranking and not starting intermittently mimicking a fuel pump going bad after a lot of testing I finally found it was the corrosion causing the no start issue. Mine would crank and run fine and then all of a sudden have the no start
 

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Nix my suggestion on swapping PCMs, I don't think computers can be swapped without dealer flashed VINs. Do you hear the fuel pump 'click' when you turn the key on or only hear it clicks when the 'check engine light' comes on then it starts? It just sounds like the PCM's works only when it's warmed up and goes through its checks then when it's sitting cold and the PCM cools off, your problems comes back. That's why I was thinking your computer was going bad. Have you check it for codes ?
 

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Discussion Starter · #6 ·
Wattapunk said:
Nix my suggestion on swapping PCMs, I don't think computers can be swapped without dealer flashed VINs. Do you hear the fuel pump 'click' when you turn the key on or only hear it clicks when the 'check engine light' comes on then it starts? It just sounds like the PCM's works only when it's warmed up and goes through its checks then when it's sitting cold and the PCM cools off, your problems comes back. That's why I was thinking your computer was going bad. Have you check it for codes ?
Can't get it started to take it to be checked.
 

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My '91 does exactly the same thing. I have done all of the before mentioned to no avail. The only thing left is to change the ECM out. I removed it already to get the numbers off it, it was really simple to do. Now the dealership I called said that my particular one was discontinued but you can get re-manufactured one online for a couple hundred bucks. Or hunt the bone yards for one.
 

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It could be the crankshaft position sensor or the sensor circuit is bad. Look under the jeep just behind the engine at the top of the bellhousing on the driverside for the sensor. check to insure the wires are not grounding to any metal surfaces. If the wires are good then might be a bad sensor. Is your jeep throwing any codes?
 

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Having a bad crank position sensor shouldn't throw a code but a new one I like 80 bucks so I found if I clean it off evey now an again it won't act up
 

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Discussion Starter · #11 ·
i found out that the capasators in the ECU were bad,they would get cold, causing the problem of having to wait for it to turn over,once they warmed up it would turn over, they finnaly went bad. wasnt getting spark or fuel, hopefully that fixs the problem.
i will let you guys know the out come, got the ECU out yesterday. Thanks again for all the help!
 
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