What is the high idle speed after ignition?

It is normal that the idle speed is too high when starting. Cars need high speed to make the engine work normally as soon as possible, and they need rich mixture, so the air intake and fuel injection will increase, resulting in high speed. Sustained high rotation speed is generally the reason for excessive carbon storage. Cleaning the throttle and idle motor in time can usually solve the problem.

Idle speed is generally set at the time of design, and there is no problem of low or high. In EFI engine, the idle speed will be higher when the car is cold, and it will automatically decrease gradually with the increase of engine temperature. Generally, the idle speed of a gasoline engine is 700-850 rpm. When the air conditioner is turned on, the electrical appliance is turned on, and the steering wheel is turned on, the idle speed will increase slightly.

Extended data:

Treatment method of continuous high idle speed of automobile

1. When the engine water temperature is low, the air conditioner is turned on, and the engine voltage is low, ECU programming should appropriately increase the idle speed. Under this normal condition, if the engine water temperature is normal, the air conditioner is not turned on, and the idle speed is high, it means that the system is faulty, which may be an electronic control system or a mechanical system.

2. If the idle speed is too high due to mechanical failure, be sure to check whether the intake pipe leaks, whether the vacuum pipe falls off and whether the intake pipe is damaged (the intake manifold of Volkswagen engine is mostly rubber pipe). Because the air intake of the engine is very small at idle speed, if there is air leakage, it will cause high idle speed.

3. After cleaning the throttle body and idle speed control valve, the engine may have a high idle speed after starting, which requires a learning process for the computer. Because the engine idle speed will decrease after the throttle body and idle speed control valve are dirty, in order to stabilize idle speed, ECU will control the opening of idle speed control valve or throttle valve to increase the intake air, thus stabilizing idle speed. After cleaning, the ECU also controls the air intake according to the original opening, and the engine idle speed will increase.

References:

Baidu encyclopedia-idle speed