Engine Parts - Cummins Fuel Injection Pump C5336065 — The high-pressure injection pump of a diesel fuel system. Driven by the engine, its pumping elements deliver metered fuel to each injector in firing order at the pressure the system requires; the governor or electronic metering unit on the pump holds delivery and timing as speed and load change. The same part number can carry different plunger and governor settings depending on the engine emission configuration, so appearance alone does not prove interchangeability. Before fitting, check that the drive taper and flange register match the part being replaced, and make sure the fuel circuit is clean and free of swarf; prime the pump with clean diesel and bleed the air out before the first start, because running it dry will score the plungers and cam. When replacing, compare the number on the old pump's plate, C5336065, character by character with the number on this order; adjacent numbers look almost identical, so never substitute on appearance or prefix alone.