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A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine.
More details:
A knock sensor allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop.
The knock sensor responds to spark knock caused by Pre-detonation of the Air/Fuel mixture. As the flame front moves out from the spark plug ignition point, pressure waves in the chamber crash into the piston or cylinder walls resulting in a sound known as a knock or ping. This is caused by using a fuel with a low octane rating, overheating, or over advanced timing. Sometimes it can be caused by hot carbon deposits on the piston or cylinder head that raise compression. A knock sensor is comprised of Piezoelectric materials; Crystals that when impacted, generate a voltage (same idea as a BBQ ignitor). This voltage is monitored by the computer, and when an irregularity is detected, the computer corrects timing in VVT (variable valve timing) engines, or triggers a DTC Diagnostic Trouble Code) in older vehicles.
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Does a knock sensor ECM error mean that sensor is bad or that the sensor is just reporting a knock in the engine?
The sensor is bad. A properly-functioning knock sensor allows the ECM to advance timing until it senses a knock. It then retards timing until the knock just barely goes away allowing for optimal gas mileage.
What sensor is bad if my dodge durango won't start?
Crank angle sensor or coolant temprature sensor are the two favourites that will cause a non start
Can an oil pan drain gasket cause a engine to start knocking and cause a good engine to go bad if placed on the car wrong?
It could be the cause of the knock only if the gasket was bad and leaked out almost all the oil.
What does a bad sensor in a car transmission do?
A bad sensor can cause the vehicle to shift at the wrong time or not at all.
Will the knock sensor cause A car to fail a smog test?
Yes. Any faulty emissions control sensor, including knock sensors, will result in an automatic fail of any emissions control test, period. It doesn't even matter if your vehicle's actual exhaust emissions are within acceptable limits. In most cases, once it is determined that a sensor is bad, the test is ended immediately, and considered failed.
