Knock Retard PCM signal.
08-24-2006, 11:03 AM
#1
Knock Retard PCM signal. I have been wanting to log KR with my LM1/LMA2 and heard it cant be done. The reason it has been said to be impossible to do this is because it is said that knock retard is something that happens entirely inside the PCM and there's no need for an output signal. Well...... what about logging the knock sensor's input to the PCM? I have been told that knock sensors work like an actual microphone and the signal to the PCM is A/C current and as you know most data logging devices work on a 0-5 DC volts so that rules this option out. My whole reason for this post is that last night I was looking at a schematic of the PCM plugs and seeing what every pin did or went to and found one labled "Spark Retard Signal". Has anyone ever heard of this wire, used it, or measured the voltage?
