Fault Cases of Isuzu 4HK1 Diesel Engine

Fault Cases of Isuzu 4HK1 Diesel Engine

Fault case 1: The engine cannot start after changing cylinder head gasket

Fault phenomenon: Phase position of camshaft is not correct.

Fault cause: The installation of camshaft is not correct.

Fault analysis: For the uniqueness of CMP (Camshaft Angle Sensor), incorrect installation position will make ECM not receive right signal and engine cannot start. 

 

Fault case 2: The camshaft sensor cannot start after changing O ring. 

Fault phenomenon: It can't start, having no alarm.

Fault cause: The replaced o-ring is a deputy factory part. So the diameter of o-ring greater than the original parts, which causes unsuitable mounting clearance between sensor and gear of camshaft. The signal is not up to standard.

Fault analysis: This kind of sensor has higher requirement for signal accuracy. If the distance between the sensor and the camshaft is out of scope, it will result inaccurate signal. ECM cannot recognize the signal and the engine cannot start.

 

Fault case 3: The engine can start after overhaul, while having very large shake, unstable revolving speed and large smoke.

Fault: have no alarm just as the above phenomenon. 

The reason: Circuit of terminals of CKP wiring harness is virtually connected because of personal carelessness during installation.

Fault analysis: Because line connection is intermittence. ECM received unstable signal while cannot be treated as fault for alarm. Unstable signal has impact on control on engine although have no alarm.