Mxs backfiring /popping exhaust

Discussion in 'Trucks [ Eighteen Wheelers ]' started by barbwire625, Dec 31, 2013.

  1. Gear head

    Gear head Medium Load Member

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    No codes normally it will through a code for low vva pressure.
     
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  2. morehp

    morehp Medium Load Member

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    I have seen them with housings snapped and Iva solenoid hanging from the wires, no oil press codes logged just a code for the solenoid.
     
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  3. Gear head

    Gear head Medium Load Member

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    Yes me too but there is always a code because of the abnormal oil pressure when the ecm trys to activate the iva.
     
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  4. JohnP3

    JohnP3 Road Train Member

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    Broken injector springs, broken valve spring usually intake, or the IVA.
    Just a thought!
     
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  5. manasteel

    manasteel Light Load Member

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    If I remember right, seems like some of the mxs had an issue with cam sensor gap being to close, and needed to be shimmed out.
     
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  6. barbwire625

    barbwire625 Bobtail Member

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    Thanks, no broken springs or anything. And the cat dealers around me can't find anything wrong. Waiting for a chance to get on a dyno. Maybe replicate the problem, I hope!
     
  7. possum42

    possum42 Bobtail Member

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    So what was the final diagnosis? I've had the exact same issue for a couple years now.
     
  8. Oscar the KW

    Oscar the KW Going Tarpless

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    I have a 625 NXS doing this intermittently, ever figure out what it was?
     
  9. barbwire625

    barbwire625 Bobtail Member

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    I had a valve that was wearing into the head. It took 5 shops to figure it out. Ran over head at I27 repair in Amarillo. Took him like 2 seconds to see that one valve was 1/4" taller than all the others
     
  10. possum42

    possum42 Bobtail Member

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    Not the good news I was hoping to get but, at least now I know what to look for come spring. Thanks!