5ek cat power loss

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Trev91, Jan 16, 2022.

  1. Trev91

    Trev91 Bobtail Member

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    I have a 95 peterbilt 379 with a 5ek it currently has a 500 file in it. The truck has 370 rears and a 15 speed sitting on tall rubber. The truck seems to fall on its face when going up a small hill. Even when pulling on flat ground it seems to struggle to get from 50 to 75 almost like it’s running out of fuel. You can stay in it as long as you want and the pyro won’t get over 750. I’ve changed fuel lines transfer pump ran the over head and I’m still having the same issue. It has around 90psi of fuel pressure at idle and over a 100psi at 1500rpm. It has a brand new cac and pulls about 38psi under hard pull. Doesn’t miss or have any blow by the truck seems to run really well until your trying to pass someone or cruise up a hill. A friend of mine has an identical truck engine rear ends and trans and it will run off and leave mine any suggestions?
     
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  3. lester

    lester Midwest's #1 Feed Hauler

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    What turbo are you running and is that a modified 500 file? 38lbs of boost, you must have something modified
     
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  4. BoxCarKidd

    BoxCarKidd Road Train Member

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    Set up to check fuel pressure while on the road if that is not what you are doing.
     
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  5. AModelCat

    AModelCat Road Train Member

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    2nd the above. Fuel demand is way more when you've got your foot into it at 1500 RPM vs in neutral at 1500 RPM.
     
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  6. Trev91

    Trev91 Bobtail Member

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    It’s a stock 550 wastegated turbo with the waste gate unhooked. As far as the file the fls and fts has been changed.
     
  7. Trev91

    Trev91 Bobtail Member

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    Would fuel pressure be different at the port vs the pressure gauge on the dash?
     
  8. lester

    lester Midwest's #1 Feed Hauler

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    If you have fuel pressure gauge in the dash that is sufficient. I don't have any suggestions for your power problem but you are going to grenade that turbo sooner or later
     
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  9. lester

    lester Midwest's #1 Feed Hauler

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    Why not put a different file in it? Try a 550 BS file
     
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  10. Star Rider

    Star Rider Road Train Member

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    Check your hand primer pump for a flipped disk or blockage. It is rare but have seen it happen . A problem in the primer pump won't affect pressure but will affect flow
     
  11. wore out

    wore out Numbered Classic

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    Put a glass sight tube in line on suction side then move it to the return. Air in the fuel system can mimic retarded timing.
     
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