weird afr issue for open loop tuning

[Wingman520]

trying to do a summer based open loop tune... been using what russk has said awhile back to enable pe at all times to make the commanded 14.7 stay locked, BUT it doesn't anything from about 20% throttle and below it want's to go as high as 16.1 afr on the commanded if i have the pedal at 0% when coasting or above 20%-23% throttle it locks 14.7 fine...

i have no idea what table is making this happen and would like to know if this is able to be fixed in some form or fashion to keep the afr locked at 14.7? thanks in advanced and tune i'm using for open loop and the scans are down below

[MMGT1]

Closed Loop adders are still in play in your tune there man. Need to 0 out the adder table and set the Open Loop afr to 14.7 in all cells. Are you using the BETA version to tune? If not, you need to contact support and get it. Without the BETA you do not have access to the tables. Looks like you are close there on using that method without the OL tables. Try setting the coolant temp to 250 and see if it makes you hold the OL, in the OL tab there if you dont have the BETA version

[Wingman520]

using beta version 2.23.598 since they update daily i try to update it once a week so i'm current... which one do you have that your running on?

showing my open loop afr is 14.7 across the board for open loop and afr adders are non existant in open loop... coolant temp to enable closed loop is 284 deg f

def confused on which tables i have for adders still on any help on which tabs your seeing enabled would be much appreciated... also during tuning i turn off closed loop and disable fuel trims just to make sure it's in open loop even though the tables set in the file are supposed to keep it in open loop

[Russ K]

Yes, you have the open loop AFR table set up correctly at 68*F and warmer, but I would return the colder temp AFR back to stock. This will allow better cold starts. No need to set the PE at 0% with the addition of these open loop tables.

And the AFR adder table is correct at 0, I normally leave the adder table at 0 when the tune is done.


Russ Kemp

[Wingman520]

Yes, you have the open loop AFR table set up correctly at 68*F and warmer, but I would return the colder temp AFR back to stock. This will allow better cold starts. No need to set the PE at 0% with the addition of these open loop tables.

And the AFR adder table is correct at 0, I normally leave the adder table at 0 when the tune is done.


Russ Kemp

Ok I recall you saying having pe enabled to try and get the 14.7 afr for non pe tuning then revert to normal settings for tuning pe while commanding 2nd gear ... I had the colder temp AFR set to see if it was a table thing for giving me such a lean afr for 20% throttle and under... They are at stock now on my normal tune this tune is for open loop tuning only... The scanning still baffles me to why it won't lock 14.7 afr

[Russ K]

Looks like the AFR Adder table is the cause, but just set up the open loop tables the way I mentioned and the commanded AFR will stay where you want.

Russ Kemp

[Wingman520]

Looks like the AFR Adder table is the cause, but just set up the open loop tables the way I mentioned and the commanded AFR will stay where you want.

Russ Kemp

so for the open loop afr adder table just set that back to stock and set the open loop afr to 14.7 for 86 and above? if so then i'll try this out tomorrow and follow up with scans if the issue persists

[Wingman520]

tried scanning today and no success... below 5500 hz or so it's showing a commanded afr of yet again up to 16.1.... scans and attemps for making the afr lock at 14.7 are provided

[gn2beatu]

Is this at 0 throttle, and is decel fuel cutoff enabled or disabled?

[Wingman520]

Is this at 0 throttle, and is decel fuel cutoff enabled or disabled?

Don't have access to dfco tables on here... It's while in drive not during coast... During when the throttle is 20% throttle and below (like just holding speed or accelerating slightly) or 5500hz on the maf and below from what I've found out in the scans. Idk if it's just how the pcm is tuned or something I'm missing completely

Also I have tried disabling deceleration enleanmeant. Didn't change anything

[MMGT1]

Fuel:Open And Closed Loop:Open Loop: "AFR ADDER"; "0" that table out. You are commanding the 16.5 in that table.

[MMGT1]

You are running around 30g/cyl and 2000 rpm when it happens. In that table that whole region is set to put you at 16.5:1
0 that table out and leave Open Loop AFR vs Coolant the way you have it now, that one is good

[Wingman520]

Fuel:Open And Closed Loop:Open Loop: "AFR ADDER"; "0" that table out. You are commanding the 16.5 in that table.

good observation (not sounding mean it is a complement honestly) where i'm puzzled in this entirely is my op that had the first tune i used has that table completely zeroed out and regardless if i change that or not it still commands 16's for my afr... my WOT ltft is great even if these afr's are being achieved.... i tried taking the afr i'm getting by 14.7 to try to change the percentage of fuel so that it would be close to 14.7 afr during cruise but when i did my ltft went -25 yet the afr was closer to 14.7.... sadly i don't have a scan of this or i would post it


i'll be making a video of this if i have to, because it's getting really annoying that i'm not able to lock my afr on the cruise side properly even though my ltft trims at WOT are consistent and below +/- 2%....


i'm almost considering it to be an impala thing, because all the pontiacs i know running the same engine are able to lock this afr when i tune this way no issues whatsoever