12746656
Fuel Injection Pump · General Motors
Injection and high-pressure pumps for diesel engines: inline, distributor and common rail systems, failure patterns and replacement checks
The injection pump, or high-pressure pump, generates the pressure needed for fuel injection; in older inline and distributor pumps, the pump itself sets injection quantity and timing mechanically or electronically, while in common rail systems the high-pressure pump feeds a continuous supply into a rail, from which the injectors are supplied independently of the pump stroke.
Delivery rate, cam profile and governor design are matched to the engine family, emission stage and power class; on electronically controlled pumps, the software is additionally linked to the specific engine control unit. The assignment list on this page comes from official US EPA certification documentation.
Wear on pumping elements or plungers shows up as starting difficulty, power loss and uneven running; a cracked drive shaft or a failed quantity control valve causes a pressure loss throughout the system; fuel contamination has a particularly strong effect on high-pressure pumps because of their tight manufacturing tolerances.
Replacement is matched by part number rather than housing size, since outwardly identical pumps can have different delivery rates; check the drive shaft, sealing rings and fuel connections for condition; after replacement of electronically controlled pumps, matching to the engine control unit and bleeding the high-pressure system are required. Price and availability are not covered on this page.
Excludes price and availability — those come from the supplier.