Can someone explain how the knock sensor circuit works on a 92Z? With the dark blue wire hooked up to the knock sensor, i get 2.39 volts at the wire (by probing the wire at the ECM.) With the knock sensor unhooked i get 4.75 volts at the wire (by probing the ECM.) I know that the 4.75 volts is the reference signal. When i measure the resistance of the knock sensor, i get 3900 Ohms. When the knock sensor detects knock, does it increase or decrease the resistance? I know that resistance increased = current decrease = voltage decrease. So is it a resistance increase(causing a voltage decrease) that triggers the ECM? Thanks in advance.

 

Its neither, really, the knock sensor is a sort of microphone.