Stopping the fuel trims affecting WOT fueling
Nov 17, 2009, 09:34 PM
#31
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^Are you saying by adding these definitions it will eliminate the ecu's ability to make compensation/adjustment in cold weather?
I am debating if I should use these for my next tune.
I am debating if I should use these for my next tune.
Nov 18, 2009, 06:09 AM
#36
That's a good question, I switched back to verify why my AFR's were so lean and apparently crips cold 30 F air tends to lean things out a bit compared to 50-60 F air where my AFR's were around 11.5 or so. Right now the trims that used to hover around +-2 are closer to +5 to +7 so when I disabled the LTFT from effecting WOT I was at the 12.3 AFR range. I'm going to get my LTFT's back to around zero and then also alter my High Octane fuel maps a few notches richer so that I can start on the richer side of things safely and then lean it back out again if needed.
I guess if I could count on the LTFT to be more stable & accurate it would balance the tune based on intake temps and fuel used with more safety but the trouble is it almost has a mind of it's own. I'll update more when I figure out why my LTFT's are drifting so positive.
I guess if I could count on the LTFT to be more stable & accurate it would balance the tune based on intake temps and fuel used with more safety but the trouble is it almost has a mind of it's own. I'll update more when I figure out why my LTFT's are drifting so positive.
I will keep updated on this as well.
Nov 18, 2009, 07:10 AM
#39
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Can you confirm once the AFR table is fully adjusted to optimal ratio, the values will stay constant and would not go north like initially?
Since I don't have a WB yet, I won't be throwing in these definitions until I hit the dyno.
Since I don't have a WB yet, I won't be throwing in these definitions until I hit the dyno.
Nov 18, 2009, 07:15 AM
#40
For now stick with what works...
I got a high knock count of like 36 and -10 timing because my AFR's leaned out like crazy. So it does have a major impact, hopefully after you dial in your AFR map again. You can just leave it alone. If not well then this solution does not work too well.
Nov 18, 2009, 07:59 AM
#42
For those thinking about adjusting these without a wideband, I would not recommend it at this time. If your LTFT's were hanging out at +5% then you will easily go about .5 - .7 AFR leaner once those no longer add in fuel during WOT and as others have seen that can push you past the safety area.
Nov 18, 2009, 08:58 AM
#43
Indeed this won't effect the compensations for temp/baro, but I found that the LTFT's generally drift positive and add a bit more fuel in when temps are colder. I think this will still be a great fix but I'm going to change my injector scaling a notch richer and see where that puts me. That should zero out my LTFT's again and reduce how much I need to richen up my High Octane Fuel tables to make things perfect again. Basically if I can get a consistant 11.5 AFR in 80F temps and 12.0 AFR in 30F temps with no wacky LTFT's acting on those numbers without my control I'll be happy.
For those thinking about adjusting these without a wideband, I would not recommend it at this time. If your LTFT's were hanging out at +5% then you will easily go about .5 - .7 AFR leaner once those no longer add in fuel during WOT and as others have seen that can push you past the safety area.
For those thinking about adjusting these without a wideband, I would not recommend it at this time. If your LTFT's were hanging out at +5% then you will easily go about .5 - .7 AFR leaner once those no longer add in fuel during WOT and as others have seen that can push you past the safety area.
New Map AFR = NMAFR
Desired AFR =DAFR
Current Map AFR = MAFR
Actual WB AFR = AAFR
NMAFR=DAFR X MAFR / AAFR
Example.
NMAFR=11.5 X 10 / 12.0 = 9.583
OR 9.6 will be put into your High Octane AFR map for a particular load/rpm.
Jut drop this forumla in excel after a WOT pull and it will tell you were to set your AFR. Then just slowly smooth out the fuel map again.
This is what my map looked like with LTFT @ WOT
This is what my map looks like now with LTFT OFF @ WOT
Nov 18, 2009, 03:31 PM
#44
Yeah I wouldn't do that.
It's very simple:
Either your cruise trim is negative (ie ECU taking out fuel?) then just leave the map as is and retune the AFR like normal
OR
Your cruise trim is positive (ie ECU adding fuel?) in which case you should multiple the fuel map by the cruise trim, flash, then retune AFR like normal
It's very simple:
Either your cruise trim is negative (ie ECU taking out fuel?) then just leave the map as is and retune the AFR like normal
OR
Your cruise trim is positive (ie ECU adding fuel?) in which case you should multiple the fuel map by the cruise trim, flash, then retune AFR like normal
Nov 18, 2009, 03:36 PM
#45
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This is great STUFF!!! Man thanks for your hard work man. What's your paypal tephra?
So when doing this we need re-map are High Oct map? If so no big deal just got to do it once! Right on!
So when doing this we need re-map are High Oct map? If so no big deal just got to do it once! Right on!