Causes of diesel engine starting difficulty
From the working principle of the engine, it can be seen that the fuel system should regularly and quantitatively inject fuel into the cylinder, and ensure the atomization quality to make the fuel burn well. The working quality of the fuel system is mainly reflected in the fuel injection time, fuel injection quantity and atomization quality. If the fuel system fails, it is difficult to guarantee the time, quantity and atomization quality of the fuel injected into the cylinder, so it is difficult to start the engine. The common phenomenon is that the exhaust pipe is smokeless (mostly without fuel), that is, there is no start sign. The main reasons are as follows:
（1).Reasons for low pressure oil circuit (insufficient oil supply,etc.)
1.There is no oil or insufficient oil in the tank, the oil pipe is broken, the air inlet is broken, the connecting piece is loose, water enters the fuel, the fuel filter and overflow valve are blocked, and the filter screen is blocked.
2.The fuel tank switch is not opened or the air hole of the fuel tank cap is blocked;
3.The pipeline between fuel tank and fuel injection pump is blocked;
4.There is air leakage in the pipeline between the oil tank and the oil transfer pump, which causes air to enter the oil circuit;
5.The filter screen of diesel engine or fuel transfer pump is blocked;
6.The overflow valve of the fuel injection pump is not sealed;
7.Water has seeped into the oil circuit or the diesel used is of the wrong brand.
（2）Reasons for high-pressure oil circuit:
1.The plunger coupling of the fuel injection pump is excessively worn, and the internal leakage is large, and the fuel supply cannot meet the starting requirements;
2.The fuel quantity regulating mechanism of the fuel injection pump is stuck, which makes the plunger unable to rotate or the rotation amount is too small;
3.The oil outlet valve is poorly sealed, resulting in no oil supply or insufficient oil supply;
4.The injector needle valve cannot be opened due to carbon deposition or sintering
5.The opening pressure of the injector needle valve is adjusted too high;
6.The injector orifice is blocked;
7.There is air in the high-pressure oil pipe or its connector is loose.
8.The injection pressure is low, the injection atomization is poor, the needle valve of the multi-layer injector is stuck, and the injector adjusting spring is broken.
