The knock sensor is attached to the side of the cylinder block to sense engine knocking. A knocking vibration from the cylinder block is applied as pressure to the piezoelectric element. This vibration pressure is then converted into a voltage signal which is relayed to the ECM. If engine knocking occurs, ignition timing is retarded to suppress it.



With that said, is it possible to use a volt meter to indicate when engine knock occurs, in aid for using nitrous or a turbocharger?

 

The way I monitor knock is to look at the timing. You should see a steady rise until it plateaus. If you see any retardation then you know you had some knock.



But you could set a meter on AC and watch the output. I use to back probe the ECU connector with solid 20ga wire to use as pickups.

 

I guess low tech is trick again. A digital meter you can afford is likely to be too slow to display any short duration signals like the occasional zing from a knock sensor, but a properly selected analog (with a real-live moving needle driven by a magnet) meter will twitch at the least provocation.

 

I've got an OBDII scanner and logger you connect to a laptop. It records a log in ECU clock ticks. Very fast. OBDLink

 

There used to be knock sensor "gauges" back in the day 10-15 years ago. They never became popular. Its better to monitor other things and fix the problem BEFORE it happens.

EGT, Wideband O2, etc... Those help you tune and warn you before knock/detonation happen. If you don't have them and just have a knock sensor/gauge...you know you had detonation, but not why! So you really didn't learn anything.



As RED stated..OBD-II software/cable will show you the knock sensor value if you really wanted to see it/watch it in action.