False Knock?

[tinindian77]

I've been chasing a spark knock issue off and on for about 6 mos now. It seems that no matter where I put the spark tables, I'm getting a retard reading, usually when the engine is lugged.
I wanted to get some opinions at this point as I'm feeling I may be overlooking something simple. Maybe I just need to move my downshift earlier to prevent some of the lugging (with larger cam)? Maybe I really do have spark knock and need to run extra low timing? Or maybe I'm overlooking another area in my tune that could be a contributor?

Changes Made: I've posted 2 different tunes with snapshots. One tune includes a table that I had customized over time and continually pulled timing from the sore spots (which seemed to make no difference). The second includes a stock LQ4 table that I pulled from repositories. I've installed 2 new OEM knock sensors and cable, balancer, have tried it in SD mode with 02's disabled, New motor mounts, nothing making contact underneath (such as exhaust).

Engine Config: LQ4 basically stock with a cam upgrade (216/224 @ .050, .551/.551, 114), 54lb injectors, shorty headers, duel exhaust with mufflers and resonators w/o cats, cold air box, stock truck intake, stock drive by wire throttle body, 4L60E, 3:42 rear.

Background: This is an 05 Avalanche that came with a 5.3 that was swapped with a 6.0 (ATK HP93) crate engine. I've been running it for around 3 years now and have never been overly impressed with the performance (advertised at 460hp). I would like to try a fast intake and larger TB, but I want to get these kinks worked out before I make any further changes.

In my research I've seen suggestions of adding octane booster to a low tank. I plan to try that, but I figure pulling the timing back should also rule out spark knock. I'm running 93 octane.

Thanks for any thoughts/suggestions.

[CranknChrome]

Pretty much need to start over. Your ve is all over the place and with that cam it is curving in the wrong place all together. Timing is also all over the place and not smooth. That cam starts making power after 1200rpm. Not before it. Ve is going to be less before that and at peak shouldnt be over 100 unless it is forced induction.
going to take a lot of studying to figure out how everything works. Also if you deleted the cats you will have to turn off rear o2 sensors. There is a whole lot to learn to do this yourself. But it can be done. This forum and youtube has everything you need to learn.

[tinindian77]

I appreciate the feedback.
That just it... I have started over. The VE table is where my snapshots have told me to go. And I have no doubt that the timing tables look crazy. As of late I've just been trying to correct the areas where it's detecting knock and then go from there. But the issue with that is that no matter how much timing I pull I'm still showing a knock reading. I've not worried so much about smoothing the tables due to having so much knock showing up. I just recently turned my MAF back on, more less to monitor and make sure I didn't have any misfires maybe from a leaning out injector.
The VE cells being over 100 have always bugged me, but again, that's what the recordings suggest it wants. Even back when I was tuning with just narrow bands and before I upgraded the injectors, the cells had to go over 100 to satisfy the lean conditions.
It has run better in the past with the VE over 100 like they are and the timing advance higher. That's what's driving me crazy.
You're the first that I've heard say that the rear O2's have to be disabled. Everything that I have read suggest that the rears do not affect fuel trims. And mine aren't even throwing a code.

Thanks again for looking.

[blindsquirrel]

If you pull significant timing out or increase octane and it still 'knocks' the same amount in the same areas it's not real actual spark knock, it's picking up some other mechanical noise.

[blindsquirrel]

Am I gonna have to go dig for another Edmund Hillary quote?

screenshot.21-08-2022 15.45.28.png

If you collected some data and it told you to build that ^^^, then the data is not to be trusted.

[tinindian77]

That's been my suspicion "Data cannot be trusted".
Thanks for your feedback.
I'll admit, I had to google to see who Edmund Hillary was. What a perfect analogy!

[djv86]

i am very new to hpt although ive used efilive a while now and i put at atk460hp 5.3 in my friends 1999 and at wot 27* it would say 8kr. we turned timing to 18* and still had 8kr set it at 0* and still showed 8kr. ive been reading the older os produce false knock. we installed a 2001 os in the truck and it runs great. not sure what year your os is although we went with a little later year os and the knock retard situation was no longer.