Knock Sensors

[clemsonteg]

I'm having trouble with the knock sensors on my 5.3 from a 03 Silverado. I replaced them along with the harness. All GM parts ordered from Amazon. I'm on my second set of sensors and I keep receiving low voltage codes on both banks. I've gone through the GM trouble shooting guide and I have the correct resistance which is dead on 100k ohms. I do see some voltage fluctuate while running which is good according to the guide, but it doesn't list the tolerance for the voltage to be considered too high or too low. Does anyone know what values at minimum I should be seeing?

[clemsonteg]

Going to test some more today, but I am seeing 100 to 300 millivolts during normal operation.

[BR3W CITY]

Are you able to view Kr at all, or only sensor voltage?

Overtightening the sensors in the hole can damage them, the harness section can get damage/shorted, and occasionally its just a bad part in the box.

[clemsonteg]

Originally Posted by BR3W CITY

Are you able to view Kr at all, or only sensor voltage?

Overtightening the sensors in the hole can damage them, the harness section can get damage/shorted, and occasionally its just a bad part in the box.

I am not able to view anything at the moment. I have a wireless OBD scanner on order to view some data using my smart phone.

I bought a brand new GM harness and new GM sensors from Amazon (prime membership got me free 2 day shipping). I replaced the originals and a few days later had the codes pop up for low voltage. Amazon sent me 2 more sensors free of charge because I thought they may be defective.

On the second attempt I was extra careful to clean the wells and I made sure to not over-tighten them (torqued to 15 ft-lbs). The DTCs appeared again for low voltage.

It is hard to imagine that I ended up with 4 bad sensors, but I guess if they all came from the same batch it could be possible.

I pulled the wires from the pcm today to see if there was any inconsistencies from the PCM to the KS harness and everything checks out. Without knowing what voltage is 'too low', it is hard to say if what I have now is good or bad. With no access to HP tuners, I am not sure if it could be something in the tune which is causing it to malfunction in some way or if that is even possible.

[clemsonteg]

One more item to note is that I was a little off on my previous estimates. At idle I see around 50 millivolts of AC voltage and around 250 millivolts during normal operation.