How to judge the failure of the plunger and the oil delivery valve couple?

When the diesel engine is working, loosen the high-pressure oil pipe joints of the fuel injection pump in turn. If a single pump does not produce oil or little oil, the speed and sound of the diesel engine will not change significantly, indicating that the plunger couple of the cylinder is or The plunger spring has failed.

If the pump oil of each cylinder is normal, but there are still problems in operation, stop the machine, loosen the joint of the fuel inlet pipe of the fuel injection pump, and press the hand pump of the fuel delivery pump. If the oil can be pumped continuously, it means that the fuel injection pump of a certain cylinder The oil delivery valve assembly or spring is damaged.

If it is difficult to start the diesel engine due to excessive wear of the plunger coupling, first remove the air from the oil circuit, use a screwdriver to pry up the lower seat of the plunger spring or the adjustment bolt, and pump oil at a faster speed. Or no pressure, indicating that the plunger coupling has been severely worn; if the pressure is particularly large, it may be that the fuel injector is blocked or the needle valve of the fuel injector is stuck.

After confirming that it is not easy to start due to excessive wear of the plunger coupling, you can first try to increase the oil supply advance angle. If you still cannot start, you can adjust the maximum oil quantity limit screw on the governor to increase the oil supply. At the same time, the fuel injection pressure of each cylinder can be slightly reduced to achieve the purpose of starting in an emergency.

Of course, when there are on-board accessories, replacing the plunger or the delivery valve assembly is the best solution.