During the operation of the diesel engine, the circulating fuel supply cannot be automatically adjusted according to the load changes, resulting in the speed fluctuating and the failure of stable operation, commonly known as "wandering" or "panting". In the case of such a failure, the diesel engine cannot work normally at the least, reducing the operating efficiency and quality; in the worst case, the diesel engine will stop when the load is heavy. At this time, the following aspects should be checked and eliminated:
1. Speed regulator failure
A. The elastic force of the speed regulating spring is weakened. Insufficient spring elastic force will reduce the speed regulating sensitivity of the speed regulator, increase the stable range of the diesel engine speed, and fluctuate. At this time, the speed regulating spring should be replaced.
B. Excessive wear of the oil pump oil adjustment arm and the speed regulating lever fork groove, the drive plate and the thrust plate cone surface will cause the speed regulator to lag behind and cause "wandering". At this time, the worn parts should be replaced to restore the normal matching clearance.
C. The internal lubrication of the speed regulator is poor or the oil in the speed regulator is too dirty, too thick, or the surface of the moving parts is damaged, causing jamming, which hinders the movement of the moving parts, lags the speed regulation, and causes the diesel engine speed to be unstable. The elimination method is: clean the inside of the speed regulator with diesel, replace the oil in the speed regulator, and repair or replace the damaged parts.
2. Oil circuit failure
A. The low-pressure oil circuit is blocked and the oil supply is not smooth. The solution is to clean and unblock the low-pressure oil circuit.
B. Insufficient fuel in the fuel tank or blocked vent hole in the fuel tank cap causes insufficient fuel supply. The solution is to add enough fuel and clear the vent hole in the fuel tank cap.
C. The cracking of the oil pipe and the loose pipe joints cause air to enter the low-pressure oil circuit. In addition, the wear of the hand oil pump of a multi-cylinder diesel engine can also easily cause air to enter the oil circuit. The solution is to replace the oil pipe and hand oil pump and tighten the pipe joint.
D. The sealing of the oil outlet valve of the injection pump is poor or the positioning screw is loose. The solution is to grind the oil outlet valve and tighten the positioning screw.
E. The injector is unstable. The solution is to replace the injector needle valve pair.
3. Fuel injection pump failure
The wear of the plunger pair, the oil delivery valve pair and the wheel of the slave pump of a multi-cylinder diesel engine causes inconsistent oil supply pressure in each cylinder, and improper adjustment of the injection pump will cause inconsistent oil supply. At this time, it should be readjusted on the test bench. In addition, the cylinder gasket of a multi-cylinder diesel engine is burned, the valve seal is not good, the piston ring is excessively worn, etc., which makes the cylinder compression poor or does not work, which will make the diesel engine speed unstable. The solution is to replace the cylinder gasket, piston ring and grind the valve.
