MAF Scaling - Open/Closed Loop Fueling info

[solidONE]

Originally Posted by Wepeel

Are there really only 4 LTFT ranges for this car? I know on my STI there were LTFT A, B, C, D, each with a progressively higher g/s range (I *think* D was >40 g/s), and then D would be what was applied during open loop WOT, so although the fuel trims weren't linear with mass flow rate it still attempted to account for that.

Disclaimer here - I'm only monitoring fuel trims from the Torque app, which is reported as "LTFT1", so not sure if that has anything to do with it. I feel like I see a lot more than 4 ranges of fuel trims. It almost seems that there's a crossover around 3k rpm... if I'm cruising at under 3k rpm at a given highway load, and then speed up to over 3k rpm, the fuel trim changes although the flow range is constant. It goes from postive something to negative something. Maybe port/DI transitions?

Can you log or view the 'Equivalence RC' values? From closely monitoring these values for the past month or so, I've seen that when the throttle is increased from a steady state throttle the 'Equivalence RC' values will go down requesting the computer for a richer mixture than the base AFR for a few seconds before going back again to base AFR's. I think what you are seeing is a result of this action.

Usually when 'Equivalence RC' value are at, say 14.9, the computer will adjust fuel trims until the actual AFR readings from O2 sensor settles at 14.6. When you open the throttle from a steady 10% to 15 or 20%, even if the base map calls for 14.5:1 the Equivalence RC will go to something like 13.8 and the fuel trims will go up until O2 reads 13.5:1 for a few seconds before settling back down to the base AFR at something closer to 14.5:1.

Edit: Scratch that... What I was describing is what happens when you come to a stop in neutral or when you firs drop to idle speed, not while cruising.

[ML]

after a couple weeks of logging and adjusting everyday, I think I'm finally at a good MAF scale with OL and CL, the corrections are less and less. Thanks guys for everything you have taught me here.

[Kodename47]

Originally Posted by ML

after a couple weeks of logging and adjusting everyday, I think I'm finally at a good MAF scale with OL and CL, the corrections are less and less. Thanks guys for everything you have taught me here.

Is this an N/A car? Don't think that hump in the mid range should be like that, can you smooth it out at all?

[vgi]

Originally Posted by Kodename47

Is this an N/A car? Don't think that hump in the mid range should be like that, can you smooth it out at all?

the axis scalings are cut off but by the look of it i would guess it's Cl/OL transition section? if he did the scaling with mafv cutoffs then merging of the cl and ol curves/maf scales was not well merged? but then he would see correction errors unless he just doesn't get enough data at that section.

[ML]

Originally Posted by vgi

the axis scalings are cut off but by the look of it i would guess it's Cl/OL transition section? if he did the scaling with mafv cutoffs then merging of the cl and ol curves/maf scales was not well merged? but then he would see correction errors unless he just doesn't get enough data at that section.

it is maf/mafv. All the CL corrections where only in the top 2 mafv or the last mafv points. All the OL corrections where in the middle. I disregarded all the jagged corrections that I think are what you are talking about. After almost 2 weeks of logging, they all showed that long hump there.

[vgi]

Originally Posted by ML

it is maf/mafv. All the CL corrections where only in the top 2 mafv or the last mafv points. All the OL corrections where in the middle. I disregarded all the jagged corrections that I think are what you are talking about. After almost 2 weeks of logging, they all showed that long hump there.

my post was rather questions to Kodename47

I don't have enough knowledge to feel comfortable to give any tuning advises. so I don't.

but I am curious about that hump too.

[steve99]

Originally Posted by ML

it is maf/mafv. All the CL corrections where only in the top 2 mafv or the last mafv points. All the OL corrections where in the middle. I disregarded all the jagged corrections that I think are what you are talking about. After almost 2 weeks of logging, they all showed that long hump there.

Agree with kodename47 hump looks a bit suspect, what are ltft like in that area, when i do cl maf scaling i deliberatly drive as smooth as possible with slow throttle movements,

but it could be ok .

[Kodename47]

If you download the latest update and use the log stats screen to view:
X axis - MAFv
Y axis - fuel status (OL/CL)
Data set - RPM
Filter - Accelerator >0 (if you can)

Check max, minimum and count to see where you're actually getting data. Its hard to get decent OL data below 3v as you need to be at WOT at low revs which I wouldn't advise. You need to get the car over 3k to get decent mid MAFv CL data, but remember you need to keep the load down enough to stay in CL. You need to work out how far you can go while in CL and the best way is to be gentle and slowly work your way up the rev range.

[Grip Ronin]

i think all these maf scaling programs hate me. ive never gotten one to take a log lol. in closed loop this one keeps saying invalid cl/ol colum when i try to load it

[Kodename47]

Originally Posted by Grip Ronin

i think all these maf scaling programs hate me. ive never gotten one to take a log lol. in closed loop this one keeps saying invalid cl/ol colum when i try to load it

Are you entering the correct column header (Fuel System Status) and the correct CL descriptor? It defaults to -1 but I think it's 2 on ours. It is on ECUtek anyway. 2 is CL and 4 is OL.

[Grip Ronin]

Originally Posted by Kodename47

Are you entering the correct column header (Fuel System Status) and the correct CL descriptor? It defaults to -1 but I think it's 2 on ours. It is on ECUtek anyway. 2 is CL and 4 is OL.

i tried changing the number still wont load up. open loop tab it just says wrong throttle % and wont open. i dont know how to edit the column header. in excel it says "fuel system stat" for the log

[solidONE]

Originally Posted by Grip Ronin

i tried changing the number still wont load up. open loop tab it just says wrong throttle % and wont open. i dont know how to edit the column header. in excel it says "fuel system stat" for the log

Did you delete the first three lines on the top of the logs? You'd have to do that for it to work correctly.

[Grip Ronin]

Originally Posted by solidONE

Did you delete the first three lines on the top of the logs? You'd have to do that for it to work correctly.

i did, still get the same thing. invalid cl/ol.

[vgi]

Originally Posted by Grip Ronin

i did, still get the same thing. invalid cl/ol.

post you log somewhere so I could take a look at. and also the log file.