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Thread: 11-16 GM Duramax owners

  1. #1
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    Default 11-16 GM Duramax owners

    I’m going to try and hit all key points to answer most questions. The 2011-2016 Duramax has a CP4 high pressure fuel pump that is known for failure. The pump grenades and contaminates the entire system with metal shavings causing thousands in repairs. Everything that has fuel ran through it has to be replaced or flushed. If you don’t get all the metal shavings out and mind you it’s fine metal shavings the new parts will fail due to the metal. 2011 and up powerstrokes use the same technology and Cummins uses CP3 which has a lift pump and does not have this issue. The CP4 has to pull fuel out the tank with vacuum which means less volume and less lubrication and has to work harder. Less volume means less lubrication because it’s lubricated with diesel fuel it’s self. The CP3 has a pump that supply’s fuel under pressure to the CP3 therefore it doesn’t fail. It doesn’t work as hard per say. Running a diesel additive will help prevent failure and keeping your fuel filter changed frequently will help. The best thing to do is add a FASS or Airdog lift pump to the GM’s. It will supply fuel to the CP4 and it has EXTRA filteration. They run about a thousand installed but you will soon see why it’s a 1000.00 well spent.

    The way the Ford is designed they have a disaster kit available

    The CP4 disaster prevention kit cannot prevent the CP4 pump from failing. What it does do is prevent the contamination from the failure from entering the high pressure fuel system.

    HOW IT WORKS

    The CP4 pump is internally lubricated by diesel fuel from the tank. After lubricating the crankcase area of the CP4 pump, fuel enters the high pressure pumping chambers and exits under pressure to the fuel rails and fuel injectors. The weakness of the CP4 pump lies in the crankcase area where a set of roller lifters ride on a camshaft. When the failure event occurs the lubricating fuel becomes contaminated immediately. Our bypass kit mounts to the CP4 pump and changes the routing of the fuel flow so that lubricating fuel from the crankcase is directed back to the fuel tank to be filtered before going through the fuel system again. Thus all fuel entering the pumping elements of the CP4 pump and leaving for the injectors is always routed through both of the vehicle's fuel filters to eliminate any chance of contamination from a high pressure pump failure.

    This one-time investment of $359 could easily save over $9,000 in repairs and weeks of downtime. It is an absolute must for any 6.7L Powerstroke owner!

    https://www.accuratediesel.com/6-7l-...ntion-kit.html

    Back to the Duramax LML. Change your fuel filters often, run an additive (I run diesel kleen) and if I were you I’d add a FASS or Airdog lift pump.

    https://www.fassride.com

    So my first CP4 failure. I am installing a lift pump on this truck now. It’s a 2016 GMC with 91k. He’s changed fuel filter twice when truck called for it. Fuel system is not covered under powertrain 100k warranty and the 16’s went to 60k warranty. Ironically GM has a service bulletin with all the parts needed for the repair. Enjoy the pictures and I’ll post some of the lift pump tomorrow.



    The Fuel Pressure Relief Valve pulled out the CP4 pump. Notice the fine metal shavings



    This is where the FPRV goes. This is inside the CP4 pump



    The dealer quoted $13,000.00 without the lift pump

    Last edited by KRT; 11-27-2017 at 08:28 PM.
    More fuel = more boost!!

  2. #2
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    Mine that you did the delete on has 130k on it now. When you want it?

  3. #3
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    Hit me up tomorrow
    More fuel = more boost!!

  4. #4
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    Quote Originally Posted by KRT View Post
    Hit me up tomorrow
    Will do

  5. #5
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    Looks like I need to make another trip? I'm at about 110,000 now
    Last edited by TheVisorGuy; 11-27-2017 at 08:35 PM.
    "They are who we thought they were"

    You can dress a fat chick up, but you cant fix stupid

  6. #6
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    Quote Originally Posted by TheVisorGuy View Post
    Looks like I need to make another trip? I'm at about 110,000 now
    This is honestly my first one although I've read the horror stories. I would if I were you.
    More fuel = more boost!!

  7. #7
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    Will do. How long does this take?
    "They are who we thought they were"

    You can dress a fat chick up, but you cant fix stupid

  8. #8
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    I'll know tomorrow and will be able to better gauge the time. A few hours I suppose.
    More fuel = more boost!!

  9. #9
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    The Ford 6.7 disaster prevention kit is CARB compliant.

    CARB COMPLAINT

    (2011 - 2016)

    Every kit now comes with a CARB compliant decal making this modification 100% street legal in all 50 States. According to our understanding, Ford's position is that any modification that is CARB compliant will not void the manufacturer's warranty.

    CARB EO# D-756-1
    More fuel = more boost!!

  10. #10
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    10/4
    "They are who we thought they were"

    You can dress a fat chick up, but you cant fix stupid

  11. #11
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    So the cliff notes version is you are good to go with a cummins. Not the case with a GM or Ford.
    cut\'em

  12. #12
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    Quote Originally Posted by Southernduck View Post
    So the cliff notes version is you are good to go with a cummins. Not the case with a GM or Ford.
    Bingo

    You want to buy a 16 F250?
    More fuel = more boost!!

  13. #13
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    Did they change anything on the '17 Powerstroke?
    Yeah, but do you consider a dog to be a filthy animal? I wouldn't go so far as to call a dog filthy but they're definitely dirty. But, a dog's got personality. Personality goes a long way.


    You might take out a dozen before they drag you from your home and skull fuck you to death. Marsh Chicken 6/21/2013

  14. #14
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    Starting in 2017 Ford uses a lift pump from the factory. They still run the CP4 high pressure pump but it’s fed by a lift pump.
    More fuel = more boost!!

  15. #15
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    Takes roughly 3 hours for lift pump install. The air dog 4g pump is a nice piece also. It is super quiet and if it fails it will still get you home. It can suck fuel thru the pump incase of a failure.

    Once you do the lift pump number 5 on the dsp feels a whole lot better

  16. #16
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    Chevrolet started using a factory lift pump as well with the L5P engine (2017)
    Last edited by KRT; 11-27-2017 at 09:03 PM.
    More fuel = more boost!!

  17. #17
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    Quote Originally Posted by santeeswamper View Post
    Takes roughly 3 hours for lift pump install. The air dog 4g pump is a nice piece also. It is super quiet and if it fails it will still get you home. It can suck fuel thru the pump incase of a failure.

    Once you do the lift pump number 5 on the dsp feels a whole lot better
    Yeah that sold me on the Air Dog and it won’t starve for fuel on #5 for sure.
    More fuel = more boost!!

  18. #18
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    I would bring you my truck but since it's a Cummings I'll just go about living my life
    Seeing these soulless vanilla ice lookin Yankees on a bassboat is worse than watching a woman get her implants taken out. It's just wrong. Get back in your Lund and go back to infisherman.

  19. #19
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    Quote Originally Posted by Griffin View Post
    I would bring you my truck but since it's a Cummings I'll just go about living my life

    That old worn out dog ain't gave up on you yet?
    "They are who we thought they were"

    You can dress a fat chick up, but you cant fix stupid

  20. #20
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    Quote Originally Posted by Griffin View Post
    I would bring you my truck but since it's a Cummings I'll just go about living my life
    I miss that truck
    More fuel = more boost!!

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