After the car is started, the idle speed is still high (1500 rpm), so it takes more than one minute to reduce the normal speed. Why?

The idle speed of EFI engine is automatically controlled by electronic equipment. Usually, when the cold car is started, the engine temperature is low, the oil fluidity is poor and the oil-gas mixture is insufficient. In order to ensure the normal operation of idle speed, the rotation speed should reach about 1200- 1600 rpm. With the continuous increase of engine working temperature, the idle speed gradually decreases, and finally remains between 600 and 800 rpm.