Legacy GT-B e-tune intermittent misfire and hesitation under load

Discussion in 'Subaru' started by jsdub1, Nov 2, 2015.

  1. jsdub1

    jsdub1 Mister

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    I have heard of too many failures of aftermarket knock sensors from our local B4/Legacy group. Not something I am willing to cheap on.

    So now I am moving on to fuel delivery and a triple check of engine wiring. Seems that when the car misfires, I can hear a click that sounds like a spark somewhere. comes from the passenger side of the bay, sounds like the back cylinder.
     
  2. Murrdawg02

    Murrdawg02 Danger to the manifold

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    Do you hear a click and then see the engine shake from the missfire? I had a Jetta with bad wires in which the spark was jumping through the insulation to the head rather than the spark plug. If it clicks every time it misfires, I would be its something in your spark/coil/ignition system. If you think you know where the click is coming from, turn off the lights and see if you can see an arc somewhere.

    I could be barking up the wrong tree, but when you said click it reminded me.
     
  3. jsdub1

    jsdub1 Mister

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    Murdawg, that is EXACTLY what happens. It's really strange because I can't see any sparks. I may have to pull that plug again and check it for damage. It's brand new but you never know. Gonna grease up those connections and wires really well too, as soon as my back allows.
     
  4. Murrdawg02

    Murrdawg02 Danger to the manifold

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    It also could be a cracked coil pack (the Jetta had that problem on top of the bad wires), Which I know you said you replaced but worth checking.
    One thing that helped me was getting a spray bottle with water and misting the coil/wire/plug as it made it want to arc more.
    Sounds familiar? Sad the video doesn't work.
     
  5. jsdub1

    jsdub1 Mister

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    It does sound familiar. It's weird because I swapped all the coils twice and it happened with both sets. I'm thinking it might be arcing in the cylinder. I will di electric grease the plug threads and move the plug one cylinder forward see if that helps / changes.
     
  6. Murrdawg02

    Murrdawg02 Danger to the manifold

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    And if you can test the plug wires or better yet swap them with someone and see. Good luck! :)
     
  7. jsdub1

    jsdub1 Mister

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    oh, it's coil on plugs, so no wires to worry about. just the wires that plug into the coil packs from the ECU. I could also grease around the bottom of the coil boots, although I thought I had done that already.

    Thanks!!
     
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  8. jsdub1

    jsdub1 Mister

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    DAMN I thought that was going to solve it, but the problem continues. It seems like the click is coming from under the intercooler.. or maybe from the injector. I am going to pull it again anyways to replace a bunch of gaskets and I will dielectric grease all the connections under there at that time. i'll pull the injectors and blow some carb cleaner through at that time. I've also got a fuel pump for a 2008 wrx laying around, I might pull the pump and see if it would work.
     
  9. Murrdawg02

    Murrdawg02 Danger to the manifold

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    Dang I had my fingers crossed. Well it sounds like whatever is clicking is causing the problem, hopefully you find it soon so you can enjoy it. You could try a can of Seafoam in the gas tank as well, if you really think its an injector issue.
     
  10. jsdub1

    jsdub1 Mister

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    I am really leaning towards an electrically controlled component failing, which doesn't really narrow it down lol. It's so inconsistent and drives fine one minute then like shit the next.. Gremlins I tell you

    Anyways I am going to pull the rest of the coils again and grease em too, can't hurt .
     
  11. Bushman

    Bushman New Member

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    Any luck? How about a smoke test for vacuum leaks....though unlikely with clicking sound.
     
  12. jsdub1

    jsdub1 Mister

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    no luck yet. I think I've narrowed it down to fuelling or vacation leak though. I feel back leak is unlikely since the problem is inconsistent. sometimes she misfires all the time sometimes she doesn't. I'm going to pull my injectors hopefully today and blast em out with carb clean or seafoam, I also threw some Lucas oil cleaner in the tank. going to order a fuel filter and rings too. that's something I haven't done. some thing is slowly failing..
     
  13. JamalS13

    JamalS13 I like cheese

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    Just a shot in the dark, but is there any way you can swap out your CAS for someone elses? Could be your culprit. I heard of that causing misfiring issue that is sometimes overlooked. But personally never encounted myself.
     
  14. jsdub1

    jsdub1 Mister

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    hmm that is something to look at as well.. I'll find a way I can test it
     
  15. jsdub1

    jsdub1 Mister

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    new symptom, when the car is cold started, the first time I try to go, i give it gas and it feels like the engine isn't getting any. Feels like driving with an injector unplugged.
     
  16. Murrdawg02

    Murrdawg02 Danger to the manifold

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    Thats brutal. I would still say electrical though I know you said feul or vacuum leak. Apparently ignition relays can fail (See post #7, fixed the OP problem)? Might be worth checking. Otherwise I would say ignitor or throttle position sensor. :\
     
  17. jsdub1

    jsdub1 Mister

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    I guess yes, it can still be electrical haha so many problems seem to cause this particular symptom.

    I am not sure about the TPS. I removed it from the throttle body and have yet to recalibrate it. The car knows and is throwing a code 31. From the manual, the ECM assumes a constant, set voltage signal from the TPS when it's throwing this code, so basically it runs without input. This hasn't changed my problem in any way.
     
  18. jsdub1

    jsdub1 Mister

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    The relay is an interesting idea, but I'd say the symptoms are quite different.
     
  19. jsdub1

    jsdub1 Mister

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    I'm justt gonna try everything free / cheap before replacing anything. Seafoam time...
     
  20. jsdub1

    jsdub1 Mister

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    update. misfire seems to be fixed! reinstalled my freshly cleaned and flow tested injectors and not a single misfire. had a bit of hesitation but that's because I haven't recalibrated my tps, I've got another throttle holy I am throwing on tomorrow to solve that!!
     
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