Hey guys

I was wondering if any 1 could explain to me what a knock sensor does and what kind of symptoms would it give if it were bad?

Im thinking mine is on its way out but im not sure.


Thanks guys.

 

A knock sensor detects knocking or pinging type noises in a engine ie. spark knock, If it sees excessive noise from an engine it will retard the timing to try to cure the noise, One way to test it is to watch your spark advance on a scanner and see if it dropping off, or a easier way is to unplug it and see if symptoms go away, Also note unplugging it will turn on the engine light

 

Well the problem is I dont have an scanner for OBD 1 . The engine is very quiet but runs rough when the code presents its self.

the light comes on when ever it feels like it too.. My dear uncle the previous owner cut the wire for some reason. IM not sure why but the wire was twisted together and taped.

Last night I cut the wire cause of corrosion and Soldered it Then heat shrinked it.

This morning truck ran great. I took it for an other drive the light came on. Then if i leave it off the light goes away.
IM thinking its the connector on the sensor its self. Not sure tho.


Edit: I played with the wire again and the light went away. SO far it has not came on. We will see tomorrow.

 

our trucks have the knock sensor? LOL i had no idea

 

LOL richphotos it is on the rear of the engine block sort of hidden by the distributor and other wires/ fuel lines

As for the sensor itself being bad it is not really common but they are not that expensive, and a connector could be tightened or picked up at a junkyard. Just make sure you torque in the new sensor.

Why did he cut the wire I do not know, BUT my wifes previous vehicle a 2000 Chev Malibu had really bad piston slap, it was so bad that the knock sensor would pull the timing back to -30 degrees, I disconnected the knock sensor and we drove that car for 3 years and over 100,000 Kms that way with no problems other then the engine light was always on.

 

Im not sure jase but I do believe it got melted by the manifold.

I wont be changing the knock sensor any time soon but I might change the plug.
Im not sure how to tighten the plug but id sure like to try.

Also these motors have 2 knock sensors
One on the rear of the motor on the passenger side and one on the driver side by the spark plugs.

 

Did about 40 miles on the truck today and NO ses light . Then the last 5 miles toward going home it came on. I pulled over and took my seat belt off and the light turned off.

This happened twice on the way home.. IM going to be changing a dryrotted vac line on the intake as soon as she cools off.

Forgot to note that the light stayed off the rest of the way home.

 

Looks like I have an bad knock sensor. After an hour of reading the GM service manual I found an diagnosis for the knock sensor.

IT says the harness has to have Approximately 5 volts and I had 3.29 volts

then it said to measure the resistance and it has to be between 8,2 .05 ohms and I had 9.31

Im not 100 % sure but i think the Sensors shot. I need Opinions

Edit: crap i just double posted.... Sigh

 

Yeah i would say its shot with readings like that.