(1) Fuel system reasons: the low pressure oil line is blocked, the pipeline is loose and leaking oil, there is air in the high oil line pressure, the technical condition of the fuel injector is not good, and the injection timing angle is incorrect.
(2) Causes of the starting device: power failure, poor contact of the electromagnetic switch, poor contact between the starter commutator and the brush, and slippage of the clutch of the starter transmission mechanism .
(3) Insufficient cylinder compression pressure: the cylinder seal is damaged and leaking, the valve is not closed tightly, and the piston cylinder liner is worn and leaking.
(4) Insufficient air intake: The air filter element is clogged.