AFR in Closed Loop

[steve99]

Originally Posted by 504

Its very interesting that this issue is resolved with subaru wrx's through the above tables, but potentially not with 32bit ECUs?

We do know that a low voltage reading to the rear o2 will tell the car its supposedly in a lean condition, therefore adding a dummy 0.3v minimum input may resolve the issue entirely. Not sure how to go about doing that

some flex kits use 0.5 to 4.5 range instead of 0-5v. this may solve issue it also allows a failsafe if you ever see 0 or 5v that means error or flex sensor fail

[504]

thoughts? I'm not clued into flex fuel tuning, but assume that it utilises LTFT to account for fuelling differences?

pulled straight from the Proecu manual

[tomm.brz]

the way ecutek wants you to use flex fuel, doesn t involve ltft
they want you to hook up a flex fuel sensor to know exactly the % of ethanol so it corrects the fueling by itself and doesn t rely on ltft, stft is sufficient

[steve99]

Originally Posted by 504

thoughts? I'm not clued into flex fuel tuning, but assume that it utilises LTFT to account for fuelling differences?

pulled straight from the Proecu manual

Yes turn off af correction #3 for sure but​ not essential to turn of ltft in open loop ive left mine active and run flex kit.
Ill try and test out the issue you and kodenane47 see but im on e85 so it may not show up


I like to leave ltft on as its not just ethanol % it accounts for its any errors in fieling due maf or temp compensations or any other error it corrects

[tomm.brz]

it's true, agree.. but if you scale it correctly i think it's enough the STFT correction, it has anyway more than +-30% of range of correction
also, i get a smoother closed loop driving with ltft disabled as ecutek suggest (Fensport also disables ltft both on NA or FI cars)
also, if you get very important vacuum leaks or exhaust leaks near lambda sensor, and the ecu tries to dump fuel, with ltft enabled you get extremely high fuel quantity dumped into cylinder and i think it could be dangerous to spark plugs or cylinder walls wash, with STFT only at least it puts a lower limit to this

anyway
ecutek just suggests to disable ltft during open loop, and i noticed now that i m talking about disabling ltft in closed loop putting afr target to 14.7

[Kodename47]

Originally Posted by tomm.brz

which calid do u use kodename?

A01G. Tried A02G and reverted back. Same on that as well I found.

Originally Posted by 504

adding a dummy 0.3v minimum input may resolve the issue entirely. Not sure how to go about doing that

A potentiometer to work out the resistance required and then wired to 12v supply would work. I've just never bothered to test.

Originally Posted by 504

thoughts? I'm not clued into flex fuel tuning, but assume that it utilises LTFT to account for fuelling differences?

It's not this. I've been doing this long enough to have tried everything (and I've read that manual more than I care to share).

Originally Posted by tomm.brz

it's true, agree.. but if you scale it correctly i think it's enough the STFT correction, it has anyway more than +-30% of range of correction

I agree. LTFT in open loop is nothing to do with this subject anyway.... unless you want to always run in open loop. Then you might be able to bypass this issue altogether.

[steve99]

Originally Posted by Kodename47

A01G. Tried A02G and reverted back. Same on that as well I found.

A potentiometer to work out the resistance required and then wired to 12v supply would work. I've just never bothered to test.

It's not this. I've been doing this long enough to have tried everything (and I've read that manual more than I care to share).

I agree. LTFT in open loop is nothing to do with this subject anyway.... unless you want to always run in open loop. Then you might be able to bypass this issue altogether.

Have you guys tried runnig ecutek closed loop do you get same issue ?

[tomm.brz]

it does not change with cl fuel control enabled, because the stock closed loop is active anyway untill 0.8 of engine load and also because you usually enable it only when the ecu is actually in open loop

but kodename could have activated it also at lower engine load since he is running a forced constant open loop mode in his car
actually i think when i have time and am not lazy, i will try do the same as him, since he actually fixed this
@Kodename47 , do you mind repeat me again how you forced open loop? i remember maybe putting the minimum open loop threshold to 14.65 afr?

[steve99]

Ok i looged again on highway, and i dont get the issue when you accelrate my afr doest go rich for 10 seconds. As you accerate it goes richer id image due tip in fueling for a wecond or two then it followes commanded afr. Coasted, cruised accelerated all ok goes straight back to 14.7 when cruising.


I have rear 02 connect flex kit A02G rom racerom 9.1 , however i am on 85% ethanol. However i only occassionally​ run petrol its possible that the issue may show up if i ran petrol and volts from flex kit was near zero volts. My flex kit is full range 0-5v zetronics kit



My ltft is active in open loop


My closed loop timers are zeroed out ie i go straight to closed loop on hard acceleration



Af#3 corrections are zeroed and all dtc associated with rear 02 zeroed theirs quite a few about 6 from memory.

[504]

Originally Posted by steve99

Ok i looged again on highway, and i dont get the issue when you accelrate my afr doest go rich for 10 seconds. As you accerate it goes richer id image due tip in fueling for a wecond or two then it followes commanded afr. Coasted, cruised accelerated all ok goes straight back to 14.7 when cruising.


I have rear 02 connect flex kit A02G rom racerom 9.1 , however i am on 85% ethanol. However i only occassionally​ run petrol its possible that the issue may show up if i ran petrol and volts from flex kit was near zero volts. My flex kit is full range 0-5v zetronics kit



My ltft is active in open loop


My closed loop timers are zeroed out ie i go straight to closed loop on hard acceleration



Af#3 corrections are zeroed and all dtc associated with rear 02 zeroed theirs quite a few about 6 from memory.

Thanks so much steve for the efforts,

I have no issue also on e85, its only when I shoot under E8 or so on the flex sensor

6 corrections!? this is the first I hear on this. I have only found two (perhaps this is the solution?)

from ecutek:

- AF Correction #3 CL Target compensation limits
- AF Correction #3 limit - Rear o2 sensor

would LOVE to see anything else you may have altered to delete rear o2 link to CL fuelling




Edit,

Noticed 4 DTC are available for rear o2. \\\\ totalling to 6

[Kodename47]

Originally Posted by tomm.brz

but kodename could have activated it also at lower engine load since he is running a forced constant open loop mode in his car
actually i think when i have time and am not lazy, i will try do the same as him, since he actually fixed this
@Kodename47 , do you mind repeat me again how you forced open loop? i remember maybe putting the minimum open loop threshold to 14.65 afr?

I leave the EcuTek CL above loads of 1. I run my own custom CL so I can run any AFR I want when cruising (now I use the car for occasional 3+ hour commutes, this is handy).

Change the minimum open loop to where you want and the OL fuel map to below that value. You can set it anywhere below 14.7 and any time the OL map is lower than that it will command open loop.

[tomm.brz]

got it, will try
thanks