I've been tuning WOT and have noticed I'm not seeing any knock counts on the scanner. I tried advancing the timing really far today until I could hear audible pinging, and it didn't pick it up. In the past it has always worked normal. I took a steel bar and tapped the side of the block and the headers...no knocks. If I tap directly on the sensor it picks it up, so it's working. How could it have become less sensitive? Shouldn't it either work or not? What voltage should I be getting at the connection?

 

Have you messed with it like relocating it or using thread sealant
on it or anything. If everything is normal then it has bit the big
one.

 

Was your Car originally a 305 ?

Did you re-use the 305 Knock Sensor ?

 

No, I haven't touched it. The car was original 5.7, so thats not it. So if I change it, do I use thread sealant? Anybody have similar symptoms? Is there any way the knock circuit components could contribute?

 

I just unplugged the connector and checked voltage with the car running. I'm measuring less than a volt on that wire. Anybody know for sure what the voltage should be, or how to properly troubleshoot a knock sensor? I hate to go buy a new one, because it seems strange that a sensor like this could still function, but not be as sensitive as it should.

 

You should be measuring voltage. You can measure the resistance. On MAF cars the knock sensor should be 100k ohms. If you replace the knock sensor don't use thread sealant. The new sensor should come with the proper sealant on it.