I hav a two -fold questions. The P72 has a knock sensor but that only works until like 5000rpm. Is there a way to raise the rpm limit and is there a way to use the knock sensor without having the ECU throw a CEL?

I ask this because I'm running a turbo setup and I've detonated a few times. Scary thing. I want to connect the knock sensor to a light so that when the engine pings, the light comes on. But I don't want to receive a CEL and I want it to work up to redline.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dominate9 &raquo;</TD></TR><TR><TD CLASS="quote">I want to connect the knock sensor to a light so that when the engine pings, the light comes on.</TD></TR></TABLE>sry dude you cant do that, the knock sensor puts out a constant amount of voltage and the ecu reads that, when it sences X amount of volts at Xrpms then it retards the timing, best to just get a JS
Safeguard
edit: it puts out more volts as the RPMs increase and even more when it knocks


Modified by Sideout at 7:51 PM 12/29/2003

 

Most likely i don't see the knock sensor working at a higher rpm, strictly because the typical engine noise of a honda motor at high rpms will cause the knock sensor to constantly trip.IMO

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sideout &raquo;</TD></TR><TR><TD CLASS="quote">sry dude you cant do that, the knock sensor puts out a constant amount of voltage and the ecu reads that, when it sences X amount of volts at Xrpms then it retards the timing, best to just get a JS
Safeguard
edit: it puts out more volts as the RPMs increase and even more when it knocks


Modified by Sideout at 7:51 PM 12/29/2003</TD></TR></TABLE>

So the ECU retards the timing when the engine pings? I didn't even know that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dominate9 &raquo;</TD></TR><TR><TD CLASS="quote">

So the ECU retards the timing when the engine pings? I didn't even know that.</TD></TR></TABLE>

 

So what exactly does the JS Safeguard do?

 

the stock Knock sensor outputs a frequency, or ampifies a frequency, it's like a little electric microphone.

Basically (very) it's looking for a sound (frequency) associated with knock. On on OEM setup, it is NOT OK for you engine to blow up, so it pulls timing when it sensess knock. An aftermarket unit, you may choose for it to not pull timing, if you think it's safe.

A problem you can run into is that the OEM unit is only tuned for the factory configuration of the motor, so reworked internals are going to throw off the acoustic properties of the motor... Please dont' ask how to re-tune the KS for the reworked motor.

-PHiZ