1. Air enters the fuel system: find out the place where the air enters the fuel system and fix it. Loosen the air bleeder on the injection pump or the connecting pipe of the fuel injector. Tightly lock the connecting pipe. Use hand to open the pump to eliminate the air in the fuel system. If it cannot be eliminated still, start the engine under the abovementioned condition.
2. Low fuel pressure: check the oil tank to see if there is oil and if there is oil leakage, serious deformation, bending, and dirt in each oil pipe. Also, check if there is any bubble inside the pipe. Check the fuel delivery pump to see if it is damaged. During the high-speed full-load operation of the fuel oil pump, the pressure of the inner cavity shall not be lower than 105KPa. Otherwise, it shall be repaired.
3. Damage of injection pump or oil injector: the cylinder shutdown testing method can be adopted to eliminate the problem. The method is as follows: under the condition that the position of the operation handle of the diesel is not changed, loosen the high-pressure oil pipe of each cylinder one by one. If a cylinder is not changed, it shows that the injection pump or oil injector of this cylinder is damaged. It is necessary to replace or repair.
4. The injection timing is incorrect. Re-adjust according to the correct method.
5. The push rod is bended or damaged. Replace it.
6. The valve clearance is incorrect. If the change of the valve clearance is obvious, check the rocker arm, push rod, valve, valve retainer, cam shaft to see if they have abnormal abrasion. Replace or repair them according to specific conditions.
The speed controller is faulty.