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
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