Is It Normal for the Car to Idle at 1500 RPM When Starting in Summer?
2 Answers
It is normal for the car to idle around 1500 RPM when starting in summer. During startup, the vehicle experiences a cold fast idle, meaning the engine is cold, and the air-fuel mixture cannot burn stably. The engine is also just beginning to operate, so the idle speed is increased to prevent stalling. Unstable idling can lead to the following hazards: High idle speed: If the car idles too high, check for loose or leaking intake manifolds, as this will significantly increase fuel consumption and accelerate engine carbon buildup. Low idle speed: If the car idles too low, there is a risk of stalling while driving, posing a safety hazard. Fluctuating idle speed: If the idle speed fluctuates, it may indicate that the spark plugs or ignition coils are not functioning properly, causing the engine pistons to misfire and resulting in severe vibrations.
I often encounter this issue when repairing cars. In summer, it's quite common for the idle speed to jump to 1500 RPM after starting the car. This is mainly because the high summer temperatures cause the engine's computer to intentionally increase the idle speed, allowing the engine to quickly warm up to its normal operating state and avoid additional wear from cold starts. Additionally, if the air conditioning is turned on, the compressor's operation increases the engine load, naturally raising the idle speed. Under normal circumstances, the idle speed should drop to around 700 to 800 RPM within a few minutes after the engine warms up. If it doesn't drop or is accompanied by shaking or stalling, it's necessary to check if the throttle body is dirty or if the idle control valve is stuck. Regular cleaning and maintenance can prevent these minor faults.
