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Common Faults in Diesel Injection Systems
2019/05/10
90% of diesel injection system malfunctions are due to: clogged filter, air in the fuel line, water in the system, faulty injectors, or abnormal pressure from the high-pressure pump.
| Common Fault Symptoms | Main Causes | |
| 1 | Difficulty Starting/Failure to Start | Air in the fuel system, clogged filter; excessive water accumulation in the fuel-water separator; insufficient pressure in the high-pressure fuel pump; stuck injectors, no fuel injection; battery/glow plug malfunction when the engine is cold. |
| 2 | Unstable idling, shaking, and easy stalling | Poor injector atomization and dripping; uneven injection in single or multiple cylinders; unstable rail pressure and insufficient low-pressure fuel supply; slight air intake in the fuel system. |
| 3 | Insufficient power, weak acceleration | Clogged fuel filter; clogged injectors, insufficient fuel injection; low high-pressure common rail pressure; poor fuel inlet; aging and collapsed fuel lines. |
| 4 | Black smoke | Excessive fuel injection or poor atomization; fuel injector dripping or poor sealing; incorrect fuel injection timing; poor diesel fuel quality or high impurity content. |
| 5 | White smoke | Poor fuel injector atomization or no atomization; low cylinder temperature (preheating failure); water in diesel fuel; late fuel injection timing. |
| 6 | Blue smoke, burning oil | Fuel injector leakage seeping into the combustion chamber; severe carbon buildup on the fuel injectors; worn piston rings/cylinder liners (accompanying symptoms). |
| 7 | Fuel consumption increased significantly | Injector dripping or poor atomization; internal leakage in the high-pressure system; abnormal rail pressure control; long-term carbon buildup and incomplete combustion. |
| 8 | Unusual noises (knocking, crisp metallic sound) | Excessive injection pressure; excessive injection advance angle; poor injector atomization, dripping. |
| 9 | Oil leaks, oil seepage | Aging of oil pipes/connectors; damage to the high-pressure oil pump oil seal; failure of the injector copper gasket seal. |
| 10 | The fault light stays on | P0087 (low rail pressure), P0088 (high rail pressure), P0201~P0204 (injector malfunction); mostly due to damage to sensors, wiring harnesses, or injectors. |
Contact Details
Chengdu Unico Machinery Co., Ltd.
Contact Person: Mr. YUAN
Tel: 0086-13881779850
