I have one strange issue. When I hit the gas, I automatically get 8*s knock straight across the board. Also, my timing disappears to 0 or negitives. It just started this. Also,IMHO, it looks like the MAP hit 100 kpa very fast and sometimes at ~30% throttle. It doesnt seem right to me. I did throw a knock sensor code for low signal or something so is this its failsafe?

2004 GMC 5.3 truck. Only mod is a catback.

Both log and tune in link: http://www.hptuners.com/forum/showthread.php?t=13533

 

Bet you money if you pull the intake off and look at the rear knock sensor, it will be rusty and corroded. There is a bulletin about replacing them and building a damn of silicone about 80% of the way around the hole for the knock sensor leaving the open part in the rear..

 

Yep, I had a buddy with an F-body we were tuning on and his threw a knock sensor code and instantly went to 0* timing and of course KR was maxed at 8*.

 

Looks like a plan tomorrow if I can find out for sure if the F body knock sensors are the same...

 

If you have a knock sensor code you are running exclusively on the low octane spark table. Is the knock audible or does it only show up in the scans?

 

Change your knock sensor. I have ran into a few of these.

 

no audible knock. It only started KR after the sensor code. Im changing them today and Ill report back.