What Causes Unstable Idle Speed When the Car Air Conditioner Is On?
1 Answers
When the air conditioner is turned on, the compressor also starts working. Since the compressor is driven by the engine, its operation increases the load on the engine. The specific reasons are as follows: 1. Insufficient Power: For most electronic throttle systems, the engine automatically increases the throttle opening to draw more air, thereby boosting output power. If the car has been used for a while and the throttle has not been maintained for a long time, carbon deposits may form, obstructing the engine's air intake. This can lead to insufficient engine power or barely enough to drive the compressor, resulting in unstable idle speed that fluctuates when the air conditioner is on. 2. Component Failure: If it's a new car, carbon deposits on the throttle are unlikely to occur so early. In this case, the issue might be due to failures in other components, such as the air intake sensor or fuel injector, causing the engine control unit to mistakenly perceive a temporary high load. It then attempts to compensate for the idle resistance by increasing the engine speed. However, when the engine speed drops, it cannot handle the load from the air conditioner compressor, prompting another increase in speed. This back-and-forth adjustment manifests as unstable idle speed.
