What does a knock sensor do?

It 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.

A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine.

knock sensor

The knock sensor responds to spark knock caused by over advanced timing. A knock is a sudden increase in cylinder pressure caused by preignition 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.

First answer by Ganderton. Last edit by Ganderton. Contributor trust: 2042 [recommend contributor]. Question popularity: 22 [recommend question]