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Author Topic: Fueltrim question  (Read 5498 times)
Jim_Coupe
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« on: October 01, 2015, 02:21:22 AM »

Hello,
Here another noob question from me.

As I am watching my log i can se that my fueltrims are around 1 - 2% at idle and low load. But att higher loads when my turbo kicks in around 4000rpm and load is 70 -100% (Lambda 0.85) my fueltrims are down -15%.  In my LAMFA table i have requested lambda 0.85 and im close to that value in actual lambda. Could this be compenated for in KFKHFM?  I dont want STFT to compensate that much under load. I must compensate somwhere else but dunno where.



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aef
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« Reply #1 on: October 01, 2015, 04:23:30 AM »

Changes on your fuel system or maf changed?

FKKVS is for fuel system if you use other injectors.
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Jim_Coupe
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« Reply #2 on: October 01, 2015, 05:00:06 AM »

I have changed MAF and injectors and did a rebuild on my fuelrail from returnless to return.

Changes are made  MLHFM for MAF and KRKTE for i Injectors. I have given it som more fuel on the top via LAMFA.

Ok, i have been studdying FKKVS for a while now by reading tons of threads here. Im thinking of setting FKKVS to 1.0 everywhere and se what STFT i get and then adjust after that. Is that a good aproach? I know about guitars FKKVS fixer but that program chrashes all the time for me. Sad

But what about KFKHFM,?
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« Reply #3 on: October 01, 2015, 06:00:44 AM »

In my aproach use:

MLHFM => use to linearize when MAF diameter or sensor are changed
KFKHFM=> use to correct amount of air (load) from diferent intake and air filter from OEM
FKKVS => use to correct amout of fuel (lambda) from diferent injectors
KFLF=> use to tune diferent lambda values

if MAF is OEM => MLHFM must remain the same
If inlet/intake are OEM => KFKHFM will remain the same, or little changes
if injectors are OEM => FKKVS will remain the same (TUVB too)


If I change MAF, intake and injectors my sequence is:
1- calculate KRKTE and TUVB (look at data sheet to TEMIM TEMINVA close values)
2- change MLHFM to new profile
3- make FKKVS, KHFM and KFLF flat
(You may want to flat LAMFA and disable BTS at this point, I usually leave it crude protection with KFLBTS, KFDLBTS disabled, LAMFA stock)

4- unplug N112 (wideband will not make STFT changes)
5- start driving around with low and medium loads.
6- make sure load is around it would be, is it´s not => KFKHFM
7- Start working on FKKVS to enrich and make all lambda =1
8- when it´s fine enough, make some basic enrichment in LAMFA to be safe enough to run some higher loads and start tuning.

(again, it´s my aproach)


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Jim_Coupe
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« Reply #4 on: October 01, 2015, 06:25:16 AM »

Ok.. Ive seen alot of diffrent aproaches tos this that has confused me a bit, but im getting some grip now.

I have set TABGBTS to 1200C to not have the KFLBTS to interfere with my tuning for now but maybe that was a bad idea.

And you said something about KFKFM to adjust load.. It funny.. in my logs i have over 150% load :0) This must be my 0.5 bar from the turbo?

Ok this is what im gonna do.

1. Flatten out FKKVS, KFKFM and KFLF
2. flatten out LAMFA
3. Change NORLA to "7" or 6"" open loop without lambda regulation. (BTW whats the tunerpro conversion factor for NORLA mine is 164 atm)
3. Make adjustments accordingly without any Fueltrims.


And now the big question. Where to adjust fuel.. Shall i just add some extra at LAMFA and let ECU calculate or go via BTS?
Or just leave LAMFA to 1 and add extra fuel in BTS.   Grin Grin Grin






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ddillenger
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« Reply #5 on: October 01, 2015, 11:39:01 AM »

Ok.. Ive seen alot of diffrent aproaches tos this that has confused me a bit, but im getting some grip now.

I have set TABGBTS to 1200C to not have the KFLBTS to interfere with my tuning for now but maybe that was a bad idea.

And you said something about KFKFM to adjust load.. It funny.. in my logs i have over 150% load :0) This must be my 0.5 bar from the turbo?

Ok this is what im gonna do.

1. Flatten out FKKVS, KFKFM and KFLF
2. flatten out LAMFA
3. Change NORLA to "7" or 6"" open loop without lambda regulation. (BTW whats the tunerpro conversion factor for NORLA mine is 164 atm)
3. Make adjustments accordingly without any Fueltrims.


And now the big question. Where to adjust fuel.. Shall i just add some extra at LAMFA and let ECU calculate or go via BTS?
Or just leave LAMFA to 1 and add extra fuel in BTS.   Grin Grin Grin








If your load is reading high chances are your MAF is overscaled.

You should learn more about the theory behind what you are doing.
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Jim_Coupe
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« Reply #6 on: October 02, 2015, 12:40:56 AM »

Yes I am reading every thread here on the forum right now about this and sucking in every bit of info i can get. I realize more and more that the tune i have bought is a total mess and i need to reset and go through it all.. I have been fooled buy the tuner that I bought this tune from. Nothing seems to add up in this tune. Getting really pissed.
I thought that the MAF was properly scaled from the start so i didnt bother to look into that. I smell a total redo of this file.
Anyway its still fun to DIY this stuff Smiley





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E85oholic
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« Reply #7 on: October 02, 2015, 06:28:22 AM »

If you changed returnless to return the fuel line, this is your issue, there is a curve that enrich to compensate the returnless behavior (less fuel when the pressure goes up in manifold)... can´t remember the name...  I guess it enrich about 15% indeed...
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Jim_Coupe
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« Reply #8 on: October 03, 2015, 12:43:16 AM »

Thanks for answer overspeed..  I think you mean FKKVS Smiley   I found the cause to the problem now and you´re right it was that table + a bad scaled MAF. Now fueltrims seem to be correct Smiley
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