Common HEUI Injector Problems and the Sources of These Problems

Both the Ford Power Stroke 7.3L (1994-2003) and the 6.0L (2003-2010) use HEUI (Hydraulic Electronic Unit Injector) style injectors. It’s a hybrid injector that uses engine oil under high pressure and fuel within the injector… Great concept, but they are prone to a couple of issues:

STICTION… As the engine oil breaks down or gets dirty, it creates a gummy residue, causing the injector’s internals to stick. Resulting in a general drag on performance and symptoms such as hard starting (especially in cold weather), roughness, and white smoke.

Recent improvements really help, especially in the 6.0L Injector. DLC (Diamond Like Coating), and a better spool valve/coil improve internal wear and friction problems. AMBAC only stocks the improved version of the 6.0L injector (INJ60B), with these your engine will perform better and longer. *AMBAC takes either injector back as core when you upgrade your injectors.

Remember, you should ALWAYS change the oil and filters when replacing injectors. One of the principle causes of injector failure is dirty engine oil. Also, it can be helpful to use an oil additive specifically designed for stictions issues.

ELECTRICAL… The wiring harness for these injectors is built into the valve cover gasket. After many miles, the passthrough wire connector can break. You’ll know it when the glow plugs quit (burnt pins in the connector) or it idles well, but as you accelerate performance breaks down. A scan might show a 1316 code (IDM) … it can’t detect each injector. A buss test on the injectors can help…if you have more than 1 injector with a weak buss test, check your wiring harness. Fortunately, the harnesses are easily replaced.

Little know fact: AMBAC (then known as American Bosch) pioneered the concept that became Unit Injection.

HPOP (High Pressure Oil Pump) and IDM/FICM issues? Contact us with questions. 800-628-6894