Not only depends on the technical conditions of itself, but also is affected by the external temperature. Starting at low temperature in winter is more difficult due to the following reasons:

In winter, the climate is cold, the ambient temperature is low, the oil viscosity is increased, and the friction resistance of the moving parts is increased, so the starting speed is reduced and it is difficult to start.

The battery capacity decreases with the decrease of temperature to further reduce the starting speed.

As the starting speed decreases, the leakage of the compressed air increases, and the heat dissipation of the cylinder wall increases, the temperature and pressure of the air at the end of compression are greatly reduced, and the delay period of diesel ignition is increased, even it cannot be burned in serious cases.

The viscosity of diesel at low temperature increases, so the injection speed is reduced. In addition, the swirl velocity, temperature and pressure of air at the end of compression are relatively low, so the atomization quality of diesel injected into the cylinder is poor. It is difficult to quickly form good combustible gas with air and ignite in time, even cannot ignite, resulting in starting difficulty.

Diagnosis of starting difficulty or failure of the KuU40-5 Excavator and a large amount of off white smoke from the exhaust pipe. The engine is difficult to start, and a large amount of off white smoke discharged from the exhaust pipe is the diesel vapor.

① The engine temperature is too low, and the diesel is not easy to evaporate and burn.

② Poor atomization of fuel injector

③ Oil supply time is too late.

④ Too little oil supply and too thin gas mixture.

⑤ Excessive air leakage of cylinder, failure to reach ignition temperature after compression.