CP4 Injection Pump

The Bosch CP4 is a high pressure fuel pump used on the 2011 to 2022 Ford 6.7 Powerstroke, the 2011 to 2016 GM Duramax LML, and the 2019 and newer Ram 6.7 Cummins.

Its reputation comes from how it fails. When a CP4 wears out internally, it sends metal particles through the entire fuel system, destroying injectors, rails, and lines. The repair often exceeds ten thousand dollars.

Protection is simple: change fuel filters on schedule, use a lubricity additive, and never run the tank dry. GM switched the L5P Duramax to a Denso pump and Ford redesigned theirs for 2023, which tells you everything about the CP4 legacy.

Mike Turner

Red Seal certified heavy duty mechanic with 14 years turning wrenches on Cummins, Powerstroke and Duramax engines across Alberta and Ontario. Mike writes the guides he wishes existed when he was apprenticing.