So, I picked up my "new" Jeep from the inspection station...

Discussion in 'KK General Discussion' started by ElCheapo, Jul 1, 2020.

  1. ElCheapo

    ElCheapo Full Access Member

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    As I was pulling out the dreaded check engine light came on and started flashing, along with rough running. They were closed, and I only live a few miles away so I went on home. Pulled the P-0301 code, cyl1 misfire, so I started looking things over and pulled #1 plug. Looked OK, but it's a NGK R plug. Seems I remember that these 3.7's don't like expensive plugs very much, so I guess a set of plugs is in my future.
     
  2. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Install 6 new plugs. They should be replaced every 30 k.
    [​IMG]
    Ya the Jeep will run a whole lot better with these.
    A flashing light means a bad misfire, stop, & turn the darn thing off... ;)
     
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  3. ElCheapo

    ElCheapo Full Access Member

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    The flashing came and went, the rest of the time it was steady. It seemed to run roughest just off idle.
    I had sprayed down the engine compartment with Simple green and hosed it off last Saturday, and though that might have caused it.
     
  4. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Yes check on your coil packs for the o-ring seal to be present.
    Use compressed air to blow away any moisture as well.
    [​IMG]
     
  5. ElCheapo

    ElCheapo Full Access Member

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    I don't think those o-rings are there. I did use air to clear the spark plug hole before removing the plug, and some moisture did come out. I was thinking "I sure hope that wasn't coolant"!!!
    Can you buy the o-rings separately?
     
  6. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Double check to make sure the 0-ring is present.
    The 0-rings were suppose to be included on all coil packs, but sometimes they may go MIA as you pull them up.
    If I see one missing, I'll always use a bright light to make sure one isn't stuck in the bore.
    Buying o-rings have no idea, but I could measure a left over one I have here, if needed.
     
  7. sota

    sota Full Access Member

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    you people re-gap plugs when you pull 'em? 30k miles I just replace with new ones. It's not like they're that expensive.
     
  8. ElCheapo

    ElCheapo Full Access Member

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    I looked over the maintenance records, and there's no entry for a tuneup, or replacing plugs, so I'll start there.
    If I pull plugs just to look them over, I'll only check gap if they look like they might be off.
     
  9. ElCheapo

    ElCheapo Full Access Member

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    The saga continues.....
    All new plugs, runs better, but still rough, check engine light still on, p0301 code still present. No O-rings on any coil pack.
    So, at this point, replace coil packs (I'll just do them all) or do a compression test to check for mechanical fault? I know some of these have a valve train problem.
     
  10. ElCheapo

    ElCheapo Full Access Member

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    Do I need to clear the p0301 code. or will it go away on it's own?
     
  11. daves06lrenegade

    daves06lrenegade Full Access Member

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    Look for another "o" ring on another coil pack and take it to Harbor Freight ... They have boxes with different size "o" rings you can compare it to... If those rings are missing then moisture can get past where they should be and cause misfires between the plugs (at the tip) and the spark plug tubes...

    Sorry I just reread your posts and saw that there were no "o" rings on any coil pack... As previously posted... There has to be some type of seal on the coil packs to keep moisture away from the top (ceramic) of the plugs... Was there also water in the other spark plug wells?

    Dave
     
    Last edited: Jul 4, 2020
  12. ElCheapo

    ElCheapo Full Access Member

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    Yeah, there was moisture in all of them.
     
  13. ElCheapo

    ElCheapo Full Access Member

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    I pulled a battery cable off, waited 15 minutes, reconnected, started it up, no light. Shut down and restarted, no light.
    Put it in reverse to back out for a test drive, dangblasted check engine LIGHT!!!!! Key on off 3 times, P0301 code.
    I think I'll grab a compression tester, and either a OBD2 reader or the app for my smartphone.
    Check compression first, if that's good I'm guessing it's coil time.
     
  14. Billwill

    Billwill Full Access Member

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    You need to clear your stored codes when you get hold of a reader.

    The "key" method of pulling codes does not erase codes.

    So if you have fitted the correct plugs, gapped correctly, and still get the P0301 code try swapping over coil packs to see if code changes.

    If still a P0301 code you need to check the wiring going to that coil pack for bad connection at the PCM or for chaffing to engine/chassis....re-plugging the PCM connectors a few times may clear up a dirty connector pin.o_O

    May be an injector #1 problem according to the manuals.
     
    Last edited: Jul 5, 2020
  15. ElCheapo

    ElCheapo Full Access Member

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    I guess I'll try that then. Thanks.
     
  16. ElCheapo

    ElCheapo Full Access Member

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    Hooray. Swapped #1 and #5 coil, code changed to p0305. I'm getting new coils, I'll just replace them all, along with the plug wires.
     
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  17. lfhoward

    lfhoward Full Access Member

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    Nice! Nailed it.
     
  18. ElCheapo

    ElCheapo Full Access Member

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    Runs like a top now!:cool: