What kind of signal does the knock sensor on an 89 TPI send? Might it be possible to build a device that could flash a "knock light" in an instrument panel? I'd like to put a little LED or light somewhere in the dash that would let me know when the knock sensor gets a sniff of some engine knock.

 

It generates a millivolt signal. You can actually catch the spike if you test the detonation sensor with an oscilloscope.

You could probably breadboard a 741 and 555, using the 741 to catch the signal at a given threshold, then latch it with the 555 long enough to recognize the warning light. You'd likely need another 741 or quad driver to operate an LED or small incandescent. The input impedeance should be plenty high enough to prevent any signal problems with the ECM.

 

I know it was really easy to do on my talon, all I had to do was wire it into the wire going to the knock sensor and then to an LED. . . . evertone with turbos had one, I don't see how it would be different on a GM??