Commanded AFR not matching AFR tables in tune

[SandSoldier]

Hello all,

I am continuing my self-tuning “journey” and once again come to yall for help.

In my tune, I have set the WOT AFR to decrement to .782 (11.5:1) by 3k RPM and hold throughout the run. When I do a pull and take a log, it seems the ECU requests an AFR value much richer than .782 and don’t know why. I have seen .72, .74, .76 but it doesn’t ever just stay at .78, does anyone know why?

(also it appears the ignition timing is doing the same thing, ECU commanding timing values lower than what i set in my tune, but I have been trying to focus on one thing at a time...)

I have tested the following:
-setting “knocking” and “overload” AFR tables to the same values
- “0”-ing the last 3 cells in the “warmup enrichment” and “warmup enrichment decrement” tables
-setting the Open and Closed loop partial throttle AFR tables to something similar to WOT at the expected load values (~2.1 with my current WGDC)
-I can set “min desired lambda/afr” to .782 but then the ECU looses the ability to richen the mixture in the event of knock (or something else important that requires enrichment)

In a previous post (viewtopic.php?f=13&t=4568&start=10) mituc mentioned the following when discussing target IDC:
“95-98% IDC may be still safe. Usually once you go above 90% you need to inspect the sparkplugs from time to time to make sure all the cylinders burn right and get the right amount of fuel. You still need to leave some IDC room in case the fuel demand increases momentarily (knock, inputs from stability control module, fuel enrichment because of high temps, and so on) so tuning your engine for more than 95 may have some implications in certain situations which can only occur like once or twice in the life of the engine (because after such events usually the engine is done).”

-i have already unplugged my SWAS, so I don’t think there should be any inputs from stability control. Do I also have to press the DSC button? I think I tested that but I honestly don’t remember, need to go back out and try again I guess.
-follow up to the previous: I saw something on other forums about just pressing the DSC button while the engine is off vs holding the button prior to starting the car. Some say it doesn’t change anything, others say just pressing the button with the engine on does not fully turn off whatever systems. Did we ever come to a consensus on this?
-“fuel enrichment because of high temps” : huh… maybe this is something. Is this BATs or coolant temp? and is there a table in VT I can see/edit regarding this for testing purposes?

*note: I will try uploading my tune and a log but have had issues in the past with this, might post a dropbox link or something
*note 2: mods: built engine, CST4, catted downpipe, 3 port EBCS, 3.5 inch intake, 3.5 bar MAP, HPFP, no Aux fuel, California 91 octane

[SandSoldier]

yep... still having problems directly uploading files

Dropbox link: https://www.dropbox.com/scl/fo/to9r6okk ... g48lv&dl=0
Google Drive link: https://drive.google.com/drive/folders/ ... sp=sharing

[mituc]

-setting “knocking” and “overload” AFR tables to the same values

This is one of the reasons why the Cobb OTS tunes blow up stock engines making less power than the stock tune. Don't do that.

-I can set “min desired lambda/afr” to .782 but then the ECU looses the ability to richen the mixture in the event of knock (or something else important that requires enrichment)

Exactly. Do not do that.

-i have already unplugged my SWAS, so I don’t think there should be any inputs from stability control. Do I also have to press the DSC button? I think I tested that but I honestly don’t remember, need to go back out and try again I guess.

There are continuous inputs from the stability control module, including inputs from a freaked-out stability control module when the steering angle sensor is disconnected. The ABS sensors will still work so the stability control module will still have input and provide input to the ECU, even though the "stability control" part will be cut out without the input from the SWAS.
On a gen2 press the DSC button for 8 (or 10?) seconds to completely disable DSC, you will still have ABS. If you lose traction (or if you're at the limit of it) the SWAS doesn't matter, the stability control module will still sense that and there will still be some enrichment, even though not as much. If you're on a gen1 speed3 then pressing DSC once will do, you do not have to disconnect the SWAS.

(also it appears the ignition timing is doing the same thing, ECU commanding timing values lower than what i set in my tune, but I have been trying to focus on one thing at a time...)

It does what it is supposed to do when the BAT and/or ECT goes up. It works as it should.

Going back to the title of this topic, in your tune you're asking for AFR of 11.5 and you're getting 11.3-ish while the BAT temperatures get pretty high. This is pretty good, almost spot-on!
However, there may be some fuel enrichment tables which we may not have access to and that work similarly with the high bat/ect ignition retard tables, and they're not the warmup-enrichment tables which are in effect when the engine starts and shortly after (as far as I know until the primary O2 sensor comes to life).

P.S.: with those load and APP settings I reckon the car feels quite "bumpy" at low/mid speeds and loads, especially when moving slowly like in parking lots...
P.S.2: APP req knocking - DON'T DO that When you have knock you do not want to still target out of the roof load. this is Cobb AP OTS tunes shit, do not import that in your tunes!
P.S.3: you can safely run more timing. 6 degrees at 6000rpm is 87OCT gas territory. Increase the timing by 0.5 increments for load 1 and above and see where it goes.