Bosch original Diesel Fuel Injector 0445120256 Cross Reference 0445120254, 0445120239, 0445120258 for Excavator Engine Replacement for OEM original new injector

Built for high-pressure common rail service, the Bosch 0445120256 (0 445 120 256) is a 120 Series diesel fuel injector cross-referenced to Cummins 5263319. Its primary confirmed appliion is the Cummins Tier 2 5.9L ISB/QSB engine family, including ISB5.9 and QSB5.9 references. Bosch identifies it as a Genuine OE injector, end-of-line tested to exact OE test specifiions and designed to deliver OE performance while meeting emission specifiions.

Within the common rail system, fuel is drawn from the tank, filtered, pressurized by the high-pressure pump, and stored in the rail. Sensors monitor system conditions while the ECU controls injection according to engine load, speed, rail pressure, temperature, and emission strategy. On receiving an electrical command, the injector opens internally and atomizes diesel into the combustion chamber. This separation of pressure generation from the injection event supports precise, electronically controlled fuel delivery for efficient combustion.

For B2B maintenance and replacement programs, the injector suits diesel engine repair, fleet maintenance, engine rebuilding, parts distribution, generator set service, and construction or agricultural equipment maintenance. Typical sales formats include a single injector, 4-piece set, 6-piece set, or full engine set. Additional references include 0256 and 5 263 319, while 5263319RX and 5263319PX are exchange or remanufactured references. Before purchase or installation, confirm fitment using the engine serial number, original injector number, ECU calibration, VIN, or equipment model; vehicle-level fitment must not be assumed.