WTB 4AGZE knock sensor

[slow_poke]

hi,

broke the knock sensor on our lemon's car. looking for either a replacement or if bypass / spoof is a good idea. we're running a bit more compression (skimmed block/head), JDM pulley and NA cams. we could mix in some race gas into our tank during the race so not really worried about KNOCK (i've heard its not that effect either), but just don't want timing retarded...

thanks
bay area.

[sirdeuce]

Mix in the race gas! If you get a good mix ratio you won't have to worry about the knock sensor. Get the engine knock free and your lap times should increase as well! Other wise, might try knock sensors from other Toyotas. I believe they were all piezo sensors, should be compatible as long as they screw into the block. I have one from a 3RZ(I believe it came from a 3RZ) that worked well enough. Had to weld a nut to a section of bolt to adapt it to the hole in the 4A block, the 3RZ has a larger thread in the boss. Or you could drill out and tap the boss in the 4A block to accept whatever size you needed. I'd offer up one of the sensors I have, but I have no clue where they are.

[slow_poke]

thanks for the advice. my current plan is to swap in resistors until the error code goes away and the timing is stable and ALSO to mix in the race gas. i've been trolling pick n pulls but so far no luck. i'll hit up MR2OC to see if anyone has another idea but if now, i'll drive on.

EVERYONE else --> does anyone have a knock sensor available where they can measure the static resistance?? that would give me a good starting point for my spoofing efforts.

thanks!

[sirdeuce]

I dug around and found a Toyota/Denso 06J129 0129 knock sensor. Should have no continuity through the sensor. It is a piezo generator and produces a small voltage signal when disturbed, tapped, bumped, etc..

[slow_poke]

thanks, but that's a bit weird. typically i think most of these sensors have a parallel resistor so when its plugged in to 12 volts the return signal is never 0V or 12V which could indicate an OPEN or a SHORT. So I'm assuming there will be some returned static voltage due to the resistance. the piezo would cause a spike in voltage that my guess the ECU would catch.

thinking about it some more (you know, knife to a gunfight sort of thinking...) there's probably some sort of RC network going on here w/ a time constant. static voltage is set by resistor. each knock event boosts the voltage a bit (due to piezo). the RC maintains the voltage for a period of time afterwhich it drains back to static voltage. get enough knocks and the voltage raises faster than it drains off and the ECU sees that as "knocking" i can't believe they are trying to catch individual knock events.

either way i think there's a static voltage that says "NO KNOCK" and a higher voltage that says "KNOCK"

thanks again, weird there was no static resistance. i'm going to keep looking to see if I can find any more info.