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labren's avatar
labren
Explorer
Feb 16, 2015

CP3 in Ram verses CP4 in Ford and GM

Is there someone that could possible explain the difference in the cp3 system that is in a Ram verses the cp4 system that is in a Ford? The high pressure Fuel Pump, is it just a brand difference or an older version? Thanks for any input on this.

48 Replies

  • BurbMan wrote:
    N-Trouble wrote:
    When the CP4 lets go it typically grenades throwing metal shavings into your fuel lines and injectors. Entire fuel system has to be replaced to the tune of $10-12k if out of warranty.


    Since Bosch has to know this, and assuming they can't stop the pump from grenading if it fails, you would think the OEMs would install some sort of screen or filter or something immediately downline of the pump to catch the debris. If the pump has to fail like that, so be it, but there has to be a way to contain the damage so that the fuel lines and injectors don't need to be replaced also. Make it a $2000 repair instead of a $12000 repair.

    What am I missing?


    I think the reason they don't do that is because a screen wouldn't do it. It would take a 2 micron filter (that can withstand 26000 PSI) to keep the debris from killing the injectors.
  • N-Trouble wrote:
    When the CP4 lets go it typically grenades throwing metal shavings into your fuel lines and injectors. Entire fuel system has to be replaced to the tune of $10-12k if out of warranty.


    Since Bosch has to know this, and assuming they can't stop the pump from grenading if it fails, you would think the OEMs would install some sort of screen or filter or something immediately downline of the pump to catch the debris. If the pump has to fail like that, so be it, but there has to be a way to contain the damage so that the fuel lines and injectors don't need to be replaced also. Make it a $2000 repair instead of a $12000 repair.

    What am I missing?
  • Both are made by Bosch. CP4 failures as stated above are huge repairs and it just takes a little bit of water. Based on what I have read in various forums, when the trucks are still under factory warranty, GM has covered these repairs and Ford generally does not. I am glad my out of warranty 6.7 Cummins has CP3. Hope this helps.
  • The CP3 was the predecessor to the CP4. CP3 has a 26k max PSI whereas the CP4 can hit 29k PSI for emissions purposes. The biggest difference from a consumer standpoint is in the way they fail. CP3 typically just start loosing rail pressure when they go bad. Replace the pump and your on your way again. When the CP4 lets go it typically grenades throwing metal shavings into your fuel lines and injectors. Entire fuel system has to be replaced to the tune of $10-12k if out of warranty.

    A lot of new Dmax owners are putting CP3 conversions on their truck as an insurance measure.