Caterpillar 3920221 Fuel Injector Assembly

Technical engineering specifications for Caterpillar 3920221 Electronic Unit Injector (EUI). This injector serves the 3500 engine family including 3508, 3512, 3516, and 3524 configurations. It features solenoid-controlled fuel metering and high-pressure injection capability for direct injection combustion systems. The unit integrates the pumping element, nozzle, and electronic actuator in a single housing. Designed for severe duty cycles in power generation, marine propulsion, and off-highway mining trucks such as the 789D. Material composition includes high-speed steel internal components and hardened steel body for wear resistance under extreme injection pressures. OEM cross-references include 20R0863 (remanufactured), 10R7234, 2501368, and 3760511. Direct replacement for Caterpillar INJECTOR GP-FUEL group.