2008 Non-Flex Fuel 5.3 Silverado

Burst Knock Retard and Displacement on Demand both Disabled.

Why would the ECM ADD Timing via the ECT Spark Timing Adder function, if the actual ECT is only like 150*, at which that whole area's "adder" function is zeroed out in the tune itself?

Amongst other things, I am logging:
Ignition Timing
Knock Retard
IAT Timing Advance
ECT Timing Advance

Is there another ECT Spark Timing Adder I am not able to see/find?

I am trying to dial in my Timing Advance, and when the ECT ADDED Timing this morning (at 65* ambient/150-ish* Coolant), it caused some Knock Retard.

Over the weekend, it was over 100* and my IAT Advance function subtracted some timing due to high IAT readings (122+*), which is what it is supposed to do, but this morning, there was no reason for the ECT Adder to even be active.

Anyone familiar with this function and why it is active if the ECT is not "hot" or "cold"?

Screenshot, Tune, and this morning's Log, all attached...

 

I'm not seeing any ECT timing advance in the log after ~138 deg F which corresponds to exactly what is in your tune. If there is and I missed it post up the time stamp in the log so I can go right to it.

 

I guess I need to learn how to read these damn logs better...

I just saw the KR in the same areas as where the ECT Adder, added, and ASSumed that was what had caused the KR...

You are much wiser than I, with HPTuners.

Using the + (Max Values), instead of the A (Average Values), I show 1-2* KR in several cells from 1200-2000 RPM, but only one cell, with 1* KR if using Average Values.

Driving my old feeble mind crazy, trying to eliminate ALL KR, using the Max Values logging...chasing my tail, in essence.

Do you use AVERAGE VALUES, or do you use MAX VALUES?
I've heard BOTH...and out of habit, have always used MAX VALUES.

Since this truck seems to have had a ton of KR from the day I got it...
What I am trying to do is get the truck out of ANY KR scenario, using 87 octane. ( I am finally close, I believe)
I want to make that table my LOW OCTANE table
Then, I plan to run strictly 93 octane, after adding 3-4 degrees to the actual HIGH OCTANE table.
My thoughts are that "SHOULD" keep me out of KR full time...and be as safe as I can possibly be.
Sound reasonable?

 

I don't use average because I'm really just looking at the direct conditions that caused each knock event individually and going from there.

Personally on a daily driven truck you are just trying to eliminate knock on you are best served by doing it how GM does it, leave the low octane timing table alone and in the dumps and set your high octane timing table with 93 octane so it's not pinging. Of course copy the high to the low when making these adjustments to ensure it's not learning down but afterwards put the low octane timing table back to stock. The knock learn factor on these trucks is relatively high so it starts to pull you down in the low table relatively quickly but it also learns up at a decent rate. This probably why GM has settled on keeping the low octane timing table in the *******.

 

I got several areas of 1-2* KR in the last few logs. Then I "Paste Special - Subtract" those numbers from MAX VALUES, and then next log, I have 1-2* KR in the cells right next to it...Getting aggravated.

What sucks is I took a LOT of timing out to try to eliminate the logged KR. From 2 or 3*, in the cruise areas,to as much as 13* out in the higher vacuum regions.
Have never heard it ping, or spark knock at all. Then or now.

Ironically, it does seem to actually run better/stronger with all the timing taken out, which I thought was weird.

 

NicD, thanks again for taking the time to reply, and for the advice.

I finally hardwired my wideband in, with new Bosch sensor, and now am able to see/tune my WOT AFR.
I ran the truck damn near out of gas, and filled it up with Top Tier 93 octane unleaded
Reflashed the High (and low) Octane Timing Table to a factory updated ecm flash, which had very different numbers than my "stock" HO table did...as in more aggressive.

Used blended STFT/LTFT AFR ERROR for tuning CRUISE, which agrees with my wideband readings (average 14.7)

Never did hear any ping before or now, so did some logging in various conditions, with and without AC on.
Saw no more than 2 degrees KR using MAX VALUE numbers
Subtracted them using Copy, Paste Special, Subtract and reflashed.
Then saw less than 1 degree in barely any cells at all, in 100 degree weather, but still subtracted anyway

I also decided to let the IAT and ECT Spark Adders remain 100% functional, which is letting both adders, "add" in cooler air, and "subtract" in warmer/hotter conditions. This seems to work very well, as the ambient temps here have been all over the place lately...65* in the morning, 95*+ in the afternoon...
Even having as many as 10 degrees higher timing than I did with 87 octane, I'm still not seeing any real worry-able KR (from .1 to a high of less than .5 degree, randomly and only at higher load, low rpm, up a hill, without downshift, and stuff like that)

Used Wideband MAF AFR ERROR to tune WOT, and now have it right at 12.4-12.5:1, (and zero KR) which I am good with.
Not even going to attempt to figure out how to tune VE on this thing, and since I have no plans for cam swap, or even longtubes, I don't think I'll need to anyway. Only took a couple reflashes to dial in MAF AFR ERROR from Idle to 5600rpm.

I did install a catch can a few weeks back, and it has "caught" some minor blowby.

All of the above, along with the minor transmission/converter tuning I have done, have made the truck much more enjoyable to drive. If rain holds off, I am going to trailer my very heavy 2000 TransAm (3700# WITHOUT me in it), and will report back how it does in that scenario.

I figure worst case, is maybe a swap to 4.10 gears, to replace the 3.73's. Truck's 2wd so I'm only a couple hours of labor away from that change if need be.

Thanks again for the replies and advice.