original 557-7634 C9 Diesel Injector High Pressure Fuel Nozzle 267-3360 387-9434 328-2574 10R-4844 553-2592 Excavator Part new injector original new injector

Engineered exclusively for the C9 engine platform, the 557-7634 fuel injector is a genuine HEUI (Hydraulic Electronic Unit Injector) assembly calibrated to factory specifications. This injector integrates seamlessly with the C9, C9 ACERT, C9 Industrial, and C9 Marine variants, all sharing the proven 8.8-liter displacement architecture. The HEUI working principle relies on the ECM calculating fuel demand in real time, while high-pressure engine oil actuates the injector intensifier piston to achieve precise injection pressure, atomizing fuel into microscopic particles for optimized combustion efficiency.

Extensive cross-reference coverage ensures full compatibility across a broad range of part numbers, including 328-2574, 328-2580, 235-2888, 236-0962, 267-9710, 267-9734, 293-4071, 459-8473, 10R-7221, 10R-7222, 20R-8060, 20R-8065, 20R-1917, 20R-8968, 387-9433, 387-9434, and 254-4330. This injector is widely deployed in 330C, 330D, and 336D excavators, 950H, 962H, and 966H wheel loaders, 730 and 740 articulated trucks, C9 generator sets, and marine power units operating across construction, mining, marine, and power generation sectors.

Built with corrosion-resistant materials and heavy-duty construction, the 557-7634 delivers long service life under demanding industrial conditions. Installation requires clean fuel supply, replacement of sealing washers, inspection of fuel rail components, and verification of fuel pressure post-installation. For optimal injector longevity, operators should use OEM-quality fuel filters, avoid contaminated diesel, monitor engine fault codes such as low fuel pressure and cylinder contribution faults, and perform preventive maintenance on a scheduled basis. A 12-month warranty backs every unit.