Cat C7 stutter

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by mission_creek, Aug 3, 2022.

  1. mission_creek

    mission_creek Bobtail Member

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    Feb 22, 2021
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    Have a 2007 peterbilt 337 dump truck with the cat c7. Starting to develop a bad stutter when under heavy acceleration or going up a hill. No codes or check engine light. HUE pump went bad 2 years ago and was replaced under a recall. When the pump went out it had poor acceleration with an engine light, not really the same issue I have now. Replaced fuel filter, no difference. I figure a fuel loss would would have an engine light. Browsing the Internet I find some posts saying they had the same problem and it turned out to be the turbo wastegate. The turbo on this truck was replaced 3 years ago as well. Anyone have any ideas? Injectors?
     
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  3. SmallPackage

    SmallPackage Road Train Member

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    Dec 20, 2019
    Marion Texas
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    My 3126B would do this every few years and it would always be an injector or two. It would develop a slight intermittent stumble at idle before it would happen as it’s way of giving me a warning of things to come.

    usually when the heui pump was failing it just died because the pump would not stay primed. I could refill the filter. Get it started. Go a mile or two slowly till it would die out again. Repeat, Till I could get somewhere safe.
     
  4. mission_creek

    mission_creek Bobtail Member

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    Feb 22, 2021
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    Wound up taking it to cat. Pump is good but 5 out of 6 injectors are bad. Leaking diesel into the crank causing oil to thin out enough to make the pump fail.
     
    SmallPackage Thanks this.
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