What is the reason for idling jitter of EFI diesel vehicles?

The causes of idling jitter of EFI diesel vehicles are as follows: the fuel supply pressure of gasoline system is too low, and the idling control system is faulty; There is no oil injection in the nozzle hole, so the atomization is poor and the oil injection quantity of each cylinder is uneven; The sensor signal is incorrect, which leads to the fuel injection signal controlled by engine ECU inconsistent with the actual working conditions; Air leakage after engine throttle; Wrong ignition time or insufficient ignition energy.

Idle instability of EFI diesel engine refers to the phenomenon that when the throttle valve is in a certain position, the fuselage shakes and swings, and the speed fluctuates from high to low. To eliminate the fault with unstable speed, please check and eliminate it from the following four steps:

Step 1: Check or replace the gasket at each joint of the oil pipe from the oil tank to the inlet screw of the high-pressure oil pipe, clean or replace the small filter screen and filter screen screw in the diesel filter element, and replace the oil pipe with sand holes or damaged inner wall. In particular, it is necessary to ensure that the low-pressure oil circuit is smooth, free of air and blockage.

Step 2: Check and adjust the valve clearance, check whether the valve ejector rod is bent, and ensure that the valve timing meets the specified requirements.

Step 3: Check the weight difference of cylinder gasket, piston ring and piston connecting rod group of each cylinder, the wear of valve camshaft and tappet assembly, and check the bending of connecting rod. Ensure that the assembly quality of all parts meets the specified requirements.

Step 4: If the fault cannot be eliminated, it should be suspected that it is the fuel injector assembly and the fuel injection pump assembly, and the professional technicians will adjust and correct it to ensure the normal operation of the oil supply system. Generally speaking, if the low speed is unstable, focus on checking the nozzle; When the medium speed is unstable, check the engine; When the high speed is unstable, focus on checking the oil pump.

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