dcmbsc

Ive never taken the intake off to fix anything so this is a first.I am trying to replace the knock sensor wire . I think I may have found the end of the wire. Where I am pointing at. But I dont no much about the motor do I have to take the other part to get to the other end or the wire?

is their any easy way to test the wire, volt meter?

dcmbsc

What ohms is the knock sensor wire sopposed to read?

scuba

Do you have alien fingers ?

dcmbsc

Can someone please give me a knock sensor voltage... 94 toyota v-6

scope103

"NO."

The knock sensor is a piezoelectric sensor, so that it sends a spike of voltage when it is "hit" hard enough (meaning, when the engine knocks). With the connector off it should be open to ground (if it has low resistance to ground the lead is most likely shorted). The connector towards the ECU is a sensor input; I don't know what voltage it would show disconnected but it wouldn't tell you anything.

I suppose you could put the output of the sensor on a digital storage scope and hit the block with a hammer to see if you get anything, but a) I doubt you have a DSO and b) I don't have any idea how hard to hit the block.

Sorry I can't be of any help.

abecedarian

+1 ... asking about voltage on the knock sensor is like asking about background noise on a regular microphone.

It's a (as mentioned) piezo-electric sensor that responds to higher frequency vibrations like what you'd have when experiencing detonation. The only way to test its operation is with an oscilloscope.... or smack the block with something metallic and watch the timing retard to baseline (and the latter isn't accurate even).

The ECU will throw a code if it thinks the knock sensor isn't working properly or if the knock sensor circuit is shorted.

abecedarian

The knock sensor wiring should have 1 wire connected to the sensor, and that wire should be wrapped with a 'shield' much like coax / cable TV cable. The center conductor connects to the sensor, the 'shield' should be grounded somewhere near the firewall.

James64

Does anybody know where it grounds near the firewall.

Thanks

bugs1961

You will have to remove the fuel injection and lower intake manifold. Here is a picture of the sensor and wire and how far into the engine you'll have to go to get to it: https://www.yotatech.com/forums/f116.../#post51266348

The pigtail goes through an opening in the cylinder head and has a rubber insulator at that point. The wire then goes into the main engine harness that goes to the ECM. The shield ground wire attaches just before the point where the pigtail passes through the head. You can see in the photo in the link that there is a wider area on the wire just before the head insulator-that is where the ground wire starts. It is integral with the wire harness and gets replaced with the wire.