Knock sensor PCM data interpretation

[cross6]

When using a scan tool, if I live graph knock sensor data with engine load, I see lots of activity that follows engine load.

Is this normal? I looked in the service manual, but only see pinpoint tests.

I tried running a tank of premium through it and no change.

All other sensors and systems check out. No codes. No audible knocking/pinging.

 

[2000StreetRod]

Knock sensor retard

Responding to an old post that I missed until now:

I have been plagued with knock sensor retard since I purchased my 2000 Sport in June 2009. I replaced the original sensor with an aftermarket one and recently with an OEM one but the problem persists. Past datalogs have indicated the spark advance has been retarded as much as 8 degrees from the knock sensor. The plot below shows engine at WOT on premium fuel climbing a hill.

Red > knock sensor retard
Green > spark advance
Blue > rpm
Brown > load
I have attempted to eliminate all vibrations that might be activating the sensor. The problem is now worse after installing an M90 supercharger. I have purchased SCT's Advantage III Pro Racer software package. I plan to adjust the knock sensor gain and the knock sensor threshold for each cylinder to determine which cylinder(s) are causing the retard.

I would appreciate any insight you have regarding the knock sensor. What does the vertical scale (300 to 1100) provided by your scan tool represent?

 

[cross6]

I'm not sure what my scan tool was showing in terms of units.

My brother in law is a Mercedes mechanic so I borrowed his euro car scan tool. It only supports generic obd2 for american vehicles so it has really weird/vague outputs and descriptions.

As to the cause:

Well as you know from my other thread I suspect chain rattle. And I for sure have a water pump with bad bearings, and a bad harmonic balancer.

So some or all of those things may have been contributing for a while. I suspect the chain rattle was enough to get picked up by the sensor but not loud enough for me to hear over the engine/fan until recently.