What causes the high idle speed of cars?

When the car is idling, it will also malfunction. For example, many car owners have encountered excessive idle speed, resulting in abnormal conditions after the vehicle is started. So what is the reason for the high idle speed of the car?

Too much carbon deposit: too much carbon deposit in the pipeline will lead to a sharp increase in the speed during ignition, leading to too high idle speed, so it is necessary to clean the pipeline in time.

Solenoid valve failure: If the idle speed of the car is still too high after the engine temperature rises after the car is started, it may be a solenoid valve failure.

Idle speed control valve failure: Because the automobile engine belongs to EFI engine, and the premise of normal idle speed of the engine is the normal control of the control valve, if the control valve fails, the idle speed of the engine will naturally be unstable.

Nozzle oil leakage: It may be that the automobile nozzle leaks oil, resulting in too much mixed gas in the cylinder. Excessive fuel injection will have an impact on the idle speed of the car, leading to excessive idle speed of the engine.

Engine throttle failure: If the engine throttle is improperly closed due to excessive carbon deposition or oil pollution, it will affect the normal work of the automobile fuel supply system, resulting in an increase in fuel injection and an increase in engine idle speed.