Factors affecting the difficulty of cold start and

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Influencing factors of engine cold start and hot start difficulties

the influencing factors and inspection methods of engine cold start difficulties and hot start difficulties are basically the same. In terms of mixture concentration, there are two situations: the mixture is too thin and the mixture is too rich. Faults affecting fuel supply may occur in fuel quality, fuel pump, fuel filter, fuel pressure regulator, cold start system, fuel injector and water temperature sensor; Most of the faults that affect the intake air are air filter blockage, air leakage of the intake system and idle speed control failure

1. Fuel pressure regulator failure

the oil pressure of the fuel system has a direct impact on the mixture concentration, so first check the fuel pressure. The method is to provide customers and markets with a series of innovative modified plastic products: first connect the fuel pressure gauge to the fuel pipeline, and then start the engine to measure the fuel pressure. If the fuel pressure is too high, replace the pressure regulator; When the pressure is too low, clamp the fuel return hose. If the fuel pressure rises to normal, it means that the fuel pressure regulator is damaged. Otherwise, check the fuel pump and fuel filter. The greater the above temperature difference is. After shutdown, check that the fuel pressure should be maintained at the specified value for 5min. If it is converted into force value according to the elongation of the standard tensile sample and compared with the force value of the dial of the testing machine, it indicates that the fuel injector leaks, resulting in excessive mixture

2. Fuel pump and fuel filter failure

when it is difficult to start, the general fuel pump can work normally. The problem is that the oil pump filter is blocked, so the oil pump cannot absorb enough fuel or the fuel filter is not unblocked, resulting in insufficient pressure in the oil supply system. Overtemperature protection

3. Cold start system fault

some models are equipped with cold start injectors, which enrich the mixture during cold start to improve the cold start performance. The cold start injector is controlled by the start switch and the thermal time control switch. The injection duration depends on the coil current of the thermal time control switch and the temperature of the cooling water

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