What are the symptoms of an idle motor failure?
3 Answers
When the idle motor is damaged, it may cause the idle speed to be too high or too low, or the RPM may fluctuate during idle. Sometimes, it may also lead to stalling at idle. The following are the reasons for unstable idle speed: 1. Engine failure: Severe carbon buildup or aging components. The solution is to replace the parts. 2. Ignition system failure: Issues with spark plugs, high-voltage wires, or ignition coils can lead to poor ignition system performance. 3. Sensor failure: Unstable oil pressure, insufficient fuel pump pressure, or incorrect readings from the intake pressure sensor. 4. Fuel line blockage: A blocked fuel line can cause insufficient fuel supply.
In my many years of repairing cars, the most common symptom of a faulty idle speed control motor is the engine speed fluctuating up and down like a dance at idle. Sometimes when stopping at a red light, the car shakes violently, making the entire cabin feel like it's rocking. Cold starts are also problematic—the engine often fails to start or stalls immediately after starting, requiring multiple attempts. When the idle speed is too high, exceeding 1000 RPM, fuel consumption increases noticeably, wasting gas money. Conversely, if the idle speed is too low, it can lead to sudden stalling, increasing driving risks. These issues are likely caused by the motor being stuck or clogged with carbon deposits, making it less responsive. If not repaired promptly, it may damage other engine components. I recommend car owners visit a professional shop for inspection, cleaning, or motor replacement as soon as they notice these signs.
When I drove my own car and encountered an idle speed motor failure, it was really annoying—the engine speed would surge up and down at traffic lights, and the car would constantly vibrate at idle, making the seats feel like they were shaking. Starting the engine in cold weather was particularly difficult, often requiring several attempts before it would fire up, and the idle speed was excessively high, wasting gasoline. These issues only got worse over time, and if not addressed early, they could lead to the engine stalling in the middle of the road, causing an accident. So when I noticed the first symptom, I went straight to the repair shop. After replacing the motor, everything returned to normal. Regular maintenance can help avoid such troubles.
