Testing tunes and LTFT restes

SO I have tune that looked real decent in some mid 70's weather without too much humidity. I want to log the same tune in hotter and way more humid weather to see the difference, but my question is should I reset the LTFT before I log more time on the same tune in different weather?

Also, I looked through the help files and not much to be explained well about the "Learn" on and off for the LTFT Reset area. Can someone maybe explain when or if I should turn on learn or not? I've just been resetting.

Thanks!

If you turn 'Learn' off, it disables the LTFT for that scanner session or until you turn it back on manually. Hard to collect LTFT chart data when LTFT is disabled.

Reset the trims before every single logging session (after up to normal, stable operating temp), otherwise you're mixing old leftover data with current data.

Quote:

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Originally Posted by blindsquirrel

If you turn 'Learn' off, it disables the LTFT for that scanner session or until you turn it back on manually. Hard to collect LTFT chart data when LTFT is disabled.

Reset the trims before every single logging session (after up to normal, stable operating temp), otherwise you're mixing old leftover data with current data.

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I have been using the reset w/o learn, it goes back to all zeros as was described, but you are saying you have to have learn to on as well as reset?

And, as I understand, you say to reset trims for every log, even when it's the same tune, but checking in differing weather?

Thanks man!

Don't turn off 'Learn' unless you have a specific reason to - and if you're trying to collect fuel trim data to make VE/MAF corrections, you need 'Learn' on, so turning it off would be self-defeating. Just hit reset if you're planning to use that log session for data to apply to the VE/MAF. Yes, eventually the LTFT will adjust itself back into line with current conditions, but it takes time, and if you don't want yesterday's data mixed in with today's, hit reset.

Quote:

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Originally Posted by blindsquirrel

Don't turn off 'Learn' unless you have a specific reason to - and if you're trying to collect fuel trim data to make VE/MAF corrections, you need 'Learn' on, so turning it off would be self-defeating. Just hit reset if you're planning to use that log session for data to apply to the VE/MAF. Yes, eventually the LTFT will adjust itself back into line with current conditions, but it takes time, and if you don't want yesterday's data mixed in with today's, hit reset.

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I see now, even though I was able to get trims to 0 out with reset, they weren't "learning" and weren't doing me much or as much good. This could be why my adjustments when used, seemed to have extreme results.
The tune I was logging did in fact act quite differently than my old school thinking. Usually in the "old days" heat and humidity would cause a lean condition, the tune was done and logged a couple good long sessions and was literally all + or -1 and a few 0's all over. When I reset, "learn on" They all went pretty rich, -3 to -4 and even worse on coast down. I guess that's the ECU doing it's job. I'm still only tuning the lower RPM until I get my WB installed, as I do get some KR blips at higher rpms, 4500 and above, but like you've all told me, I won't fix it w/o a WB or a canned tune possibly. (they generally suck) unless it comes from someone you know.

I would ask this as it seems the area I struggle with often is idle and coast down (from say a slow acceleration) to 4 to 5k rpm then let off. It's then I seem to be real lean or real rich often. I have read and read, watched all kinds of videos, but can't really seem to find where to properly adjust this and do it correctly. I am finding some idle adjustments that help a little, but not sure about the "coast down" from a higher rpm.

Don't turn the trims on OR off via the special functions panel, unless you have a specific reason to.

It will go into closed loop when the conditions are met, per whatever settings you have in the tune file, you do not need to manually turn them on. Just click Reset and then the little red X up in the corner.

Quote:

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Originally Posted by blindsquirrel

Don't turn the trims on OR off via the special functions panel, unless you have a specific reason to.

It will go into closed loop when the conditions are met, per whatever settings you have in the tune file, you do not need to manually turn them on. Just click Reset and then the little red X up in the corner.

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Ok, NOW I understand, I didn't think I had to push it to make it "green for on", I've always reset trims on a new tune, but I have logged the same tune at two different times w/o resetting, and I'm sure this is why I chased my tail a few times.
Thanks for the help!