Knock Sensor or Timing Sensor ?

[Chris Thorp]

> For an on the car test, the archives showed this:
> <http://www.audifans.com/archives/1996/09/msg02544.html>
>
> It uses an oscilloscope, but I'm guessing (And if I'm wrong...)
> that the knock sensor just puts out some small voltage or
> changes resistance when knock is present. Put a voltmeter
> or ohm meter on the leads, whack the engine block with a
> hammer (gently; you don't want to put a hole in the block)
> and see if it registers a change in voltage/ohms.


Unfortunately, you do actually need the oscilloscope.  The "knock 
sensor" is just a small microphone that bolts onto the engine.  The 
knock sensor control box then performs some black magic on the recorded 
sound from the microphone to determine if the engine is knocking or not.

-Chris