According to Repairpal.com, symptoms of a bad knock sensor include poor acceleration, knocking noises during acceleration, poor fuel mileage and a visible check engine light. The symptoms of a bad knock sensor typically occur during heavy loads or at high speeds. Autopartswarehouse.com explains that the knock sensor has a direct effect on the engine’s ignition timing. A bad knock sensor causes a decrease in acceleration and fuel mileage.
Autopartswarehouse.com adds that a defective knock sensor does not properly adjust the timing of the engine when fuel enters the cylinder. This causes the vehicle to lose fuel mileage and acceleration. Additionally, a bad knock sensor causes irreparable damage to the engine. According to Repairpal.com, the knock sensor detects vibrations and transmits data to the engine computer. These vibrations or engine noises are caused by detonation. When the knock sensor is damaged or broken, the detonation process is not regulated properly. Autopartswarehouse.com explains bad knock sensors also lead to excess engine noise. These noises are generally loud thumps and are a result of air or fuel entering the cylinder. Autopartswarehouse.com recommends identifying the symptoms of a bad knock sensor and replacing the part immediately. A new knock sensor helps avoid damage to the engine and eliminates costly repairs.