What Causes High Idle Speed During Cold Engine Start?

[MadisonRose]

The reasons for high idle speed during cold engine start are as follows: 1. In a cold state, the car needs to allow the engine to quickly enter the normal working environment after starting. Therefore, during a cold start, the engine control unit automatically increases fuel injection. By burning more fuel than normal idle speed, it rapidly raises the engine's coolant temperature, allowing the engine to quickly reach a suitable operating temperature. 2. This mainly manifests as a higher engine idle speed when cold, typically between 950-1300 RPM. Once the engine temperature rises to a certain level, the idle speed will decrease to the normal value. Relevant information about car idle speed is as follows: 1. Car idle speed refers to an operating condition of the car where the engine runs without load, known as idling. This means the car's gear is in neutral, figuratively speaking, the engine is "working without outputting power." 2. The engine's power comes from fuel combustion, which is achieved through the combined operation of the fuel injection system, ignition system, and mechanical structure. Therefore, unstable idle speed is often caused by abnormalities in these systems.