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Help! Jeep gets to operating temp then shuts off (no check engine light)

Discussion in 'TJ General Discussion' started by Kraig, Jun 10, 2018.

  1. Imapepper

    Imapepper TJ Enthusiast

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    Do you have cheap multimeter? If not, time to get one if you want to fix your own jeep
     
  2. Kraig

    Kraig New Member
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    Yeah I have one. I'm gonna try to test the cps tonight. Hoping thats the cause and not the ecm.
     
  3. Imapepper

    Imapepper TJ Enthusiast

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    Another test you could try is to disconnect the crankshaft sensor when the engine is running and cool.I would think it should throw a check engine light and also engine should stop running.Anyone confirm unplugging will throw a CEL?
     
  4. Kraig

    Kraig New Member
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    So I think I found the culprit! Took the cps off and the wires are cracked and melted. Looks like they were hitting the header. Getting a new one in the morning hopefully to solve the problem! 20180613_220210.jpg
     
  5. Kraig

    Kraig New Member
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    So I put a new crankshaft position sensor in and the jeep runs and drives good so far. Thanks for the advice and help! Hope this thread helps someone else.
     
  6. KCsTJ

    KCsTJ TJ rookie
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    If i understand correctly, the engine would run fine in open loop (cold) mode,
    But when the engine reached normal operating temp, it enters closed loop mode, where it then starts gathering input from sensors , so when it checked the bad cps, at warm up, it shut down
     
  7. abe abel

    abe abel Member

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    I just had to replace my 2nd cam censer in 4000 the first had a bad belt noise and then this time it was hard starting so I thought since I already changed the cam censer it was the crank censer it was hard starting like out of gas but I just filled tank run fine up to a shift point then fall on its face shift gears and it would run good up to a shift point it ended up being the cam censer
     

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