The idle speed of Jiefang Xichai is unstable, and the refueling is a little arched.

What you want to ask is that the idling speed of Jiefang Xichai is unstable, and what is the matter with a little arch in refueling? The engine has serious carbon deposition, and the throttle and air intake have too much scale.

1, engine carbon deposit is serious. When there is too much carbon deposit in the engine, the gasoline sprayed by the fuel injection head will be absorbed by the carbon deposit during the cold start, which leads to the lean mixture during the cold start and makes it difficult to start. In this case, only when the gasoline adsorbed by carbon deposits is saturated, it is easy to run into the car. After running into the car, the gasoline adsorbed on carbon deposits will be sucked into the cylinder by the vacuum suction of the engine for combustion, which will thicken the mixture and dilute the combustible mixture of the engine, resulting in idling jitter after cold start.

2. There is too much scale on the throttle and air intake. The change of the cross-sectional area of the airway makes it impossible for the control unit to accurately control the idle intake, resulting in the mixture being too rich or too thin and abnormal combustion.