Check my tune 408ci

[dantheman1540]

The motor is an iron 408 with PRC247 heads, 11-1 comp, 231/243 .627/.615 113lsa cam, TBSS intake, and 87mm TB. It's in a 2004 Denali that's been manual transmission swapped several years ago and was running fine with a milder 408 setup. The truck starts and idles just fine even with AC but I have been trying to tune VE and its getting knock all over the place. I reduced the timing down to 1 in some of the cells and it still wants to pull several degrees which puts it in negative timing. Also while in SD it has a terrible bucking around 1600rpm, it isn't started by a shift or blip of throttle it just comes around right when you get to that rpm in 2nd 3rd or 4th gear. If it's put back into dynamic the bucking subsides substantially. Also, it hangs rpm around 2k when rolling in neutral or clutch pushed in while rolling. I have messed with TF, TC, and rolling idle which is what saved it from stalling constantly.

Heres both files please tell me why I'm an idiot and WTF I am doing wrong.

[Ben Charles]

What injectors?

[kevin87turbot]

It appears that the knock occurs at idle and very low rpm. That's always indicative of false spark knock. You might look at a mechanical issue, such as interference between header and frame or exhaust hitting frame or something.

[dantheman1540]

I believe they are 42lb injectors same injectors its had for 4 years.

How can you determine false knock?
I had considered that already and tonight pulled the intake to check the knock sensor torque thinking I gave them some dugga duggas on accident, but they werent over torqued.

Mechanical interference is a possibility but none of the accessories have changed except the Kooks cats were gutted and it does make an odd ticking noise now that they are gutted. Almost sounds like they are leaking but I have double verified they are not. Also it has poly motor mounts now instead of OEM rubber but there is no cab vibrations like I expected.

Is there a way to lessen the knock sensor sensitivity?

Sometimes starting in second it will sense knock immediately and it runs like crap for a few seconds until finally it cleans up and is fine again.

[kevin87turbot]

Are those AC Delco knock sensors? Torqued to 15 ft-lbs? Replaced the sensor harness?

You can desensitize the knock sensors if they continue to be problematic.

There are several ways to check for detonation. There are knock boxes that allow you to listen for and/or datalog aftermarket knock sensors.