When logging fuel trims I am letting the car go into CL and I am using the LTFT from bank 1&2 average. I have read some information lately on this forum that would lead me to believe I should be forcing open loop and using the short term trims. Is this correct?
What I would do is disable LTFT and use STFT while staying in CL. Use the oem narrowband sensors for your part throttle tuning and get a wideband installed for your OL/WOT areas. Some people like to tune the car completely in OL using a wideband... only to turn back on CL and have the NBs re-correct everything (which is dumb IMO).Originally Posted by DirtyDave86
Would I be correct to disable LTFT in the file by setting min/max ECT so they do not come on? This makes sense, but I have a lot to learn here.
That would disable LTFT, yes. Personally, i think leaving LTFT and CL on and then using LTFT+STFT math gives a better result if youre tuning with narrowbands. There are several ways to get it done and some work better for some people. You can try one way and then make a new tune file with the changes from a different way and see the results yourself though.
"I don't care how it runs as long as it chop chops at idle"
Yes, in my experience you can get the car dialed in way faster using STFT vs. LTFT. I've tried both and ended up with the same result...just LTFT take much longer to settle in
My STFT is all over but the LTFT stay around -1 to +1. Considering I have been using the LTFT and going for relatively short drives, maybe I will have better luck using the ST
Appreciate the input
Appreciate the input, I have been using LTFT only and not having good results
A quick screenshot that should explain how to use what im talking about. Its already in the scanner, all you have to do is select it.
"I don't care how it runs as long as it chop chops at idle"
You still need to get steady state data but the STFT will start to settle in the longer you drive
When both are enabled you need to drive longer. The STFT is off because you don't have enough data hits on each cell. Once the STFT slowly gets close to 0-1% you will see your LTFT's are now off and that's when you copy paste the data from LTFT into your VE table. IMO if its way off I will use OL, wbo2 error. Once close I then tighten them up with CL, STFT.
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thanks I?ll check it out
So I need to use CL fuel corrections regardless when tuning part throttle with the narrowbands
Thank you
Sounds like there are a lot of ways to get it done
I really need to get a W/B O2 on the car
Thank you
Yeah, I feel that's the best way to do it considering the narrowbands are the ones doing the fuel corrections when in CL. Like I mentioned previously it's really up to you if you want to use STFT, LTFT, or LTFT+STFT.
Thanks, I'm still getting a grip on all this and appreciate your input. I'm taking the safe route and just ordered an innovate wideband and plan on setting it up via the 0-5 output and bringing it in on the AC pressure sensor.
Last edited by DirtyDave86; 03-12-2024 at 05:52 PM.
Gotcha, just make sure to reset your LTFT (if you decide to use them) via the scanner PRIOR to each log. If you disable them you won't have to worry about doing that
I use LTFT and STFT together while tuning.
If LTFT is adding 10% and STFT is -5%.. what your tuning should be moved +5%.
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I used STFT multiply by percent half and it seems to be working better. For whatever reason I can force SD, drive for an hour, and the LTFTs all settle around -2 but the STFT are all over the place from +5 to -5
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