Detroit boost issue

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by periodic, Jul 13, 2021.

  1. periodic

    periodic Bobtail Member

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    2007 Freightliner coronado, 12.7 5915 injectors(new), 550hp tune, 169011 turbo (borg). 3.42 gears. DDEC IV.

    Getting 5.3mpg hauling lighter loads (30k max), barely any power pulling up hills. My electrical boost gauge on the truck is showing 17 PSI MAX, same as when I hook it up to the computer(ecm). Installed a mechanical gauge on it and it’s getting 27 PSI on that gauge.

    New boost sensor on it as well.

    Any advice on what it could be?
     
    truckdriver31 and jamespmack Thank this.
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  3. jamespmack

    jamespmack Road Train Member

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    Still need to pressure test system. 550hp? Should be about 35psi. Your low for a 470.

    You might have multiple issues. When and who did a overhead reset last?
     
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  4. periodic

    periodic Bobtail Member

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    when I did my injectors two weeks ago. Tanner diesel. Problem was there before the overhead and injectors.

    my mechanical gauge is reading out 27 PSI. Just the ECM is not getting a correct reading.
     
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  5. truckdriver31

    truckdriver31 Road Train Member

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    have you checked the air to air boots or the charger it self for leaks.
     
  6. periodic

    periodic Bobtail Member

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    It’s not leaking. My mechanical gauge shows the correct PSI.
     
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  7. jamespmack

    jamespmack Road Train Member

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    Here we go, The whole story slips out slowly.

    Has anyone thought to out it on the dyno?
    Your correct psi is low still. Check fuel psi. How fresh is the
    Air filters and fuel filters?
     
    Last edited: Jul 14, 2021
    spsauerland and nikmirbre Thank this.
  8. little cat 500

    little cat 500 Road Train Member

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    boost leak ata more than likely junk
     
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  9. truckdriver31

    truckdriver31 Road Train Member

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    i thank so too. but he said no leaks
     
  10. little cat 500

    little cat 500 Road Train Member

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    If you read how he tested it its going to read the same ata is more than likely junk
     
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  11. periodic

    periodic Bobtail Member

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    I’ve done the boost leak test. It stayed at 30 PSI for 5 minutes. There’s no leaks.
     
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