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Low rail pressure

Discussion in '6.7L 3rd Gen Cummins' started by Oledirtypearl86, Aug 13, 2019.

  1. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    Any on have a good grasp on thease I have a 2011 3500 in my shop that came in and it had a bad tune I fixed the tune and it runs like a scalded dog till 2500 rpm and drop on its face till 3000rpm and is all good I got a code for low fuel rail pressure I read the pressure and at peak demand I'm getting 11k psi in nuteral I can get 15k psi but still fall short has anyone seen this
     
  2. 79jasper

    79jasper Chickenhawk

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    New fuel filters?
    The rail pressure sensor can go bad. But whose tuning? Check tuners botch the rail pressure, so that could be what you're seeing as well.

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  3. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    I changed the fuel filters and it's got a H&S tuner for a dpf delete and turned up just a little
     
  4. 79jasper

    79jasper Chickenhawk

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    Next step would be to watch supply pressure.

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  5. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    I looked at it a bit today between cars and it has a new lift pump I didn't get. Chance to watch the supply pressure but I'm down to lift pump or regulator
     
  6. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    So situation solved it was the lift pump I put a Airdog lift pump laying in the shop with new filters and back up to specks on rail pressure
     
  7. 79jasper

    79jasper Chickenhawk

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    That would make sense. Sometimes a hot tune is more than the factory lift pump can handle.

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  8. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    Yeah but it's not a really hot tune it's pretty mild but on the same note the truck with all the tools and service bed weighs just over 12k
     

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