I understand that retarding the ingnition timing is desirable when you're spraying. I'm wondering though, is there a way to wire a resistor across the knock sensor and trick the ECU into retarding the timing? This way you could turn on/off the "detected knock". Has anyone tried this? I have a 97 and don't want to shell out the big bucks for an ignition timing retarding controller.

 

Funny you should ask we were just talking about that today. Don't think anyone has tried has far as I know but I plan on doing some experienting.

I have tried disconnecting completely, also putting a 470k ohm resistor and compared timing to stock but there was no difference.

Thinking about trying a variable resistor across the circuit and then keep adjusting at WOT while watching the timing and see if any of the setting will cause it to pull back as though it sees knock.

 

Very interesting. I will certainly be interested in your results. I'm curious though if the knock sensor does more than affect the timing; ie: the A/F ratio, injector pulse rates etc.

Another intersting point for you. My 95 FSM describes that the knock sensor is a piezoelectric element. That means that it will actually generate voltage when it is shaken/vibrated. The CEL illuminates if the voltage is too low or too high. It doesn't list the voltage range but I'd assume 5 volts probably. That could easily be measured w/ a multimeter. If this is the case, I don't know that a resistor would do the trick. Another voltage source may be needed to replicate the voltage amount when knock is detected. Hope that makes some sense and please keep me posted. I'm looking to install my nitrous system in the next 2-3 weeks.

 

Ok good stuff. Ya it might not be that easy but like you say there are always different ways. I haven't looked into it too much yet and sometimes the fsm is very weak especially on electronic components.

I do have a spare KS too but I am more worried about screwing up the ECU by hitting it with any voltage, but we will see. As long as I keep it 5V and under, probably ok.

Don't believe it affects anything more than timing but not 100% on that, and like I said earlier, I haven't been able to affect it at all by disconnecting etc. Its very easy to monitor the timing too with the OBDII reader, so easy to detect any differences.