original 4CR0197 Diesel Engine Fuel Nozzle for 3126 Common Rail System 128-6601 155-8723 new injector original new injector

Engineered as a direct replacement for the 3126, 3126B, and 3126E diesel platform, this HEUI fuel injector carries the primary OE reference 4CR0197 and is validated against an extensive list of cross numbers, allowing distributors and service shops to consolidate sourcing for a single engine family. The 3126 is a 7.2-liter inline six-cylinder four-stroke diesel engine with a 110 mm bore and 127 mm stroke, and its HEUI fuel system relies on high-pressure engine oil for hydraulic actuation while the ECM governs injection timing and quantity. The injector is sized and calibrated to match this architecture, supporting correct fuel metering and high-pressure atomization across medium-duty trucks, school buses, transit buses, RVs, construction machines, industrial power units, generator sets, selected marine engines, and excavators.

The unit is built to deliver stable engine response, low internal leakage, and consistent spray pattern performance, addressing common field complaints such as hard starting, rough idle, power loss, high fuel consumption, misfire, and ECM injector fault codes. It is offered in new, original quality, remanufactured, rebuilt, or aftermarket configurations depending on stock availability, supporting both fleet maintenance operators and aftermarket distributors across North America, Latin America, Europe, the Middle East, Africa, Southeast Asia, and Australia.

Before installation, technicians should clean the fuel system and oil system, replace all seals and O-rings, clean the injector bore, and lubricate new O-rings with clean engine oil while following the official torque specification. After installation, bleed the fuel system, start the engine, check for leaks, scan for fault codes, and verify idle and acceleration performance. Routine use of clean diesel fuel, scheduled fuel and oil filter replacement, and water separator draining will extend injector service life and reduce the risk of premature failure.