Engine Parts - Cummins Fuel Injection Pump C5525718 — The diesel engine's high-pressure fuel injection pump, raising low-pressure fuel and sending it to each injector in sequence. Fitting causes more failures than the pump itself: the mating face between the pump flange and the gear housing must be clean and free of paint and old gasket residue, or the timing will be offset; tighten the bolts diagonally in stages to the specified torque; start the high-pressure pipes by hand before applying torque, because cross-threading ruins the sealing cone. After fitting, bar the engine over two turns by hand to confirm nothing interferes, then bleed the air and run at idle while watching return flow and exhaust colour. If idle is rough, acceleration is flat or the engine dies when hot, check supply pressure and the filter first and suspect the pump last; once the pump is confirmed faulty, replace it as a unit rather than opening the governor cover on site. When replacing, compare the number on the old pump's plate, C5525718, character by character with the number on this order; adjacent numbers look almost identical, so never substitute on appearance or prefix alone.
