[cbh148]

So my s13 SR20DET recently threw a code 34 (knock sensor) and ran like crap. Checked the wiring to the knock sensor and it seems fine -- no breaks, continuity is perfect.

Checked the voltage that the ECU is sending to the knock sensor at pin #27, and it's only 3.3 volts when I believe it's supposed to be 5 volts. What gives?

With my old knock sensor plugged in, and backprobing the harness at the ECU with the key on, that 3.3 volts is unchanged. However, with this knock sensor that I got off a friend's KA plugged in, it's 2.0 volts.

It throws the code 34 immediately with the old knock sensor. But with the used KA knock sensor, it doesn't get the code at all, but it feels slower (even though it wasn't amazing before). A lot slower. Like, can't connect the same turns drifting that it could before.

So would the 2.0 volts it's sending be close enough to the 2.5 volt signal (what it's supposed to be if there's no knock/problems) that it's NOT throwing the code 34, but it IS pulling timing and making me lose power?

Hell, for all I know, the old sensor was acting up all this time and causing power to be robbed, and it wasn't until it got fully messed up that it caused the code 34 to be thrown.

Still not sure about the 3.3 volts coming straight off the ECU though. Anybody got any insight with this? I don't mind bypassing the knock sensor with a resistor if I have to, but if it's not getting 5 volts in the first place, I wonder if I would need a different resistor to make the return signal end up at 2.5 volts -- so not the usual "1 megaohm 1 watt" resistor that everybody else seems to use.