Less than 2k after burnt exhaust valve repair. Im getting the knock and super knock codes with reduced engine power light in but no Obdii cel. I cleared the mini specific codes with my Schwaben scan tool. With scan tool plugged in I pulled up fuel pressure values. The tool has an option to show “actual value” and “set point value.” I kept on eye on both values while driving and noticed actual is very close to set point in every driving condition except deceleration/braking. When I come off freeway and brake, the actual value dips significantly below the set point, but only briefly. Strangely, this did not trigger anything. No lights. The hpfp actual and set point values are in line when superknock and knock codes were triggered once right after start up at idle and two other times at 65mph going up a long hill. So I’m not so sure it’s my hpfp. I’ve been through the super knock threads and it appears there isn’t a clear cut solution. My head was just repaired so no carbon buildup. I had injectors cleaned and tested. I didn’t replace chain because it was within spec and no rattling. I know it could be anything but I just wanted to know about the fuel pressure dipping to about 50% of set point value only when deceleration/braking.

Bump

Could it possibly be the intank fuel pump? Under deceleration the fuel in the tank would shift to the front. If the in tank pump is the back maybe it’s starving for fuel.