What are the symptoms of a bad knock sensor?
3 Answers
The symptoms of a bad knock sensor include: 1. Reduced engine power; 2. The engine makes a knocking sound; 3. The malfunction indicator light (MIL) illuminates. The knock sensor is composed of a magnetic core, permanent magnet, and induction coil. Its function is to measure engine vibration. When engine knocking occurs, it adjusts the ignition timing advance. The working principle of the knock sensor is that when vibration or knocking occurs, it generates a small voltage peak. The more severe the knocking or vibration, the higher the main peak voltage generated by the knock sensor. A specific frequency indicates knocking or detonation. When the control unit receives this frequency, the ECU recalibrates the ignition timing to prevent further knocking.
I was really frustrated when I found out the knock sensor was broken. The car made a lot of noise, with the engine producing a harsh 'clanking' sound, like metal hitting metal, especially noticeable during acceleration or uphill driving. The power was severely lacking too—even with the pedal to the floor, the car moved sluggishly, making overtaking on long trips a struggle. Fuel consumption shot up; a full tank that used to last 500-600 kilometers now barely made it to 400, and the frequent refueling hurt my wallet. The check engine light on the dashboard usually came on. At first, I thought it was a minor issue, but after ignoring it for a few days, the engine started shaking even worse, and I noticed the car was running hotter. I rushed to the repair shop, where the mechanic diagnosed the trouble code and replaced the sensor to fix it. Ignoring such problems can lead to premature engine failure, and that kind of repair isn't cheap. Don't take driving lightly—check the warning lights as soon as you hear any unusual noises.
As a long-time driving enthusiast, I've experienced knock sensor failure. The symptoms were obvious: first, the engine sound became rough, like continuous knocking; then the car accelerated slowly, with sluggish response and poor throttle sensitivity. This increases fuel consumption because the ignition timing is off, leading to incomplete combustion and wasted fuel. The engine light coming on is a common signal, and an OBD scanner will show fault codes like P0325. I addressed it promptly when discovered, because ignoring it can accelerate engine wear, leading to more severe knocking or overheating. The repair isn't too troublesome - usually just replacing the sensor - but delaying it increases emissions and isn't environmentally friendly. Always stay alert to such abnormalities when driving.
