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Intermittent misfire

Discussion in 'EFI Topics' started by USNChief, Oct 29, 2016.

  1. USNChief

    USNChief Active Member

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    08 Mastiff EFI that runs like crap, only sometimes, no power, backfire, clears up after a mile or 2 . New injectors, new intake gasket. Shop rode it with fuel pressure gauge hooked up inline, good pressure. Anybody experienced this? Could it be electronic?
     
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  2. Little-Boo

    Little-Boo Well-Known Member
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    I would check the TPS to make sure it is work within range. I don't have those number for you, but I do know if you TPS is not set right you will experience intermittent performance.

    Carlos :old2:
     
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  3. USNChief

    USNChief Active Member

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    Thanks, Carlos. I'll get on the shop. They think it's a fuel problem, but I'm not so sure. At $85.00 an hour, want to narrow down the cause.
     
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  4. DrRx

    DrRx 2007 Bulldog/2009 K-9

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    Where did you get the fuel injectors. I'm looking to replace mine.

    Thanks doc
     
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  5. dingo

    dingo Proud to be a

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    Steve, I realize you posted this in October but if you haven't resolved yet (and for others experiencing similar problems), you may want to check your coil wiring under the tank. I had a similar problem caused by a chaffed wire under that tank that would ground itself out intermittently. Would run great, then like crap. Keep us posted.
     
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  6. USNChief

    USNChief Active Member

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    Thanks man. Problem solved, turned out it was ECM module. I got a rocket ship now. Sucks I flushed that $$$ on parts I didn't need, but at least it's all brand new now. And a little satisfaction that I was right about being electronic issue.
     
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  7. dentdude36

    dentdude36 Guru

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    :chopper:
     
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  8. dingo

    dingo Proud to be a

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    Glad you got it worked out !

    I did the same thing....I ran all the diagnostic tests and the chaffe was so tiny and intermittenet that I missed it until after I replaced the coil, plug wires and thunderheart module. As Paul says, I have a bunch of good spares now.
     
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  9. DrRx

    DrRx 2007 Bulldog/2009 K-9

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    Glad you got it running. Can you tell me where you found your fuel injectors at?
     
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  10. dingo

    dingo Proud to be a

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    Sorry, I have an 06 so mine is a carb setup.
     
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  11. USNChief

    USNChief Active Member

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    Came from S&S, 2 pack part # 55-5052.
     
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  12. DrRx

    DrRx 2007 Bulldog/2009 K-9

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    Does anyone know where t get the fuel pump filter at
     
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  13. Tdubb

    Tdubb Active Member

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    Walbro filter 125-192. Same part for my 2008 EFI Mastiff. $8-$10. You'll need new oetiker clamps. Those are: small clamp 15400040(17.5RER). large clamp 15500029 (0455.0R)
     
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  14. willywill4765

    willywill4765 Member

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    Can you tell me what you did with your ECM module or how you fix yours my 07 bulldog misfires every so often also

    Sent from my SM-G900P using Tapatalk
     

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