Knock sensor - activity counts

[east302]

Truck is a 1998 Tahoe 4x4. Previous owner installed a Jasper reman 350 which now has around 60k miles on it. He also installed JBA headers.

I’m chasing a stumbling sensation that is noticeable at idle in park but more pronounced in gear and after extended highway runs. It feels like a rumbling sensation. At its worst, it feels like it is wanting to die but the RPMs never change.

In other words, it feels like a low idle (about to stall) but without an actual low idle to go along with it.

There are no DTCs or misfire counts. The one thing that stuck out on a scanner is this Knock Sensor count.

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I compared this on a 1998 K1500 truck and it read zero counts.

Is this reading a potential issue or just a rabbit hole and normal?

 

[Schurkey]

I'd say you have problems. The knock activity is "one" less than the maximum possible.

First Guess: Knock sensor is faulty, or the wire harness is faulty, or the ECM is faulty. You're not really getting knock, it's a "false" reading.

 

[studigggs]

If you can graph those PIDs you should be able to see if the KS Activity is actually resulting in Knock Retard. If not, then the scan tool may be not reporting accurately.

 

[east302]

Thanks, guys. I’ll look into the sensor, see if there’s a way to back-check the readings. I’m not that familiar with them. Will also run a scan/live graph to see if it ever retards the timing, it doesn’t look like it is.

Can I assume that if it was truly seeing 255 counts then the corresponding knock or noise would be pretty noticeable?

 

[PlayingWithTBI]

Can I assume that if it was truly seeing 255 counts then the corresponding knock or noise would be pretty noticeable?

Pull the spark plugs and look for signs of spark knock,

https://www.dynamicefi.com/SparkPlug.php