Lots of knock - EGR CEL

[Sammy_Johns]

I am running a stock ASDU bin on a 7747 with SA and BPW hacks. Base timing is about 5* advanced. It recently started throwing a EGR Code and racking up the knock count. There's about 30 minutes of street and freeway driving in the log. I don't know if the numbers in the log are typical or show any issues. I intermittently have a vibration most noticeable at idle. Actually, I should say I intermittently have a very smooth running vehicle. Any suggestions of where to go from here would be appreciated.
I posted this too soon. Obviously, I need to troubleshoot my EGR system, then do some more data logging.

Thanks.

[RobertISaar]

a guess would be that you have some EGR occurring at idle, but not anywhere near the amount commanded above that, causing the spark advance that is added due to EGR presence being enough to cause knock.

I would do a test run with EGR disabled(coolant temp enable threshold raised to maximum) and see if that helps/completely fixes the issue.

[Kitch]

Temporarily set up your dashboard to show "EGR Duty cycle", that way you can see if the EGR is disabled.

[Sammy_Johns]

One nut for EGR valve had backed off. No leak, no code. Imagine that!