I'm working on a 2014 Sierra with a 5.3L N/A with intake only, and noticed that after increasing the fuel pressure
It started to get bad knock in the lower RPM range, around 1200 to 1600. I increased the pressure in the high load Ares, and in the 1200 to 1600 RPM area, the pressure was increased from 9.6 MPa to 15 MPa.
I ran out of time trying to dial it in but, I did get rid of the bad knock by retarding ignition timing and advancing fuel SOI in those areas for right now until I have more time to work with it.
Has anyone else experience this?