Knock Sensore code P0325 in K2500 7.4

[WojTec]

If the KS are over torqued that could be your problem. Carbon fowled cylinders maybe, Bad wiring, Low quality fuel, Poor spark, timing. You need to eliminate everything as a possible cause.
You might not hear it, but if the New AcDelco sensors are torqued correctly and registering knocks and all else is correct, you have an engine problem.

Ok -so how to test Acdelco or NTK - if are working on the test bench Have you seen my video - all 4 are not giving me AC output more than 100-150mV - all internet is indicating over 1Volt.

 

[Schurkey]

Ok -so how to test Acdelco or NTK - if are working on the test bench Have you seen my video - all 4 are not giving me AC output more than 100-150mV - all internet is indicating over 1Volt.

I have not researched this. So what follows is merely a guess, and not an educated guess at that.

The knock sensors put out voltage, but extremely little amperage. Therefore, the input impedance of your test system will be critical.

Most all multimeters sold now have a "computer safe" input impedance of 10 megohm or more. But the difference between a 10-meg input impedance and a 20-meg input impedance is enough to show a difference in O2 sensor voltage; so it's probably enough to show a difference in knock sensor voltage.

Older voltmeters/multimeters had MUCH lower input impedance; which means they act as a short-circuit when connected to low-amperage devices. You can't test O2 sensors with them, and they can even cause damage to some circuits. What is the input impedance of your voltmeter?