Questions about LTFTs

[Super Sky]

1. When the battery cable is disconnected are the LTFTS lost ??

2.When we load a new tune are the LTFTs part of the tune ??

3. How many LTFT values are there ??

I working on a 2007 Redline

[5FDP]

As far as I know the LTFT is "reset" if you disconnect the battery for a given amount of time, they start over learning once the vehicle is running again. It seems around 10-20minutes of driving makes them come back to working normal again.

If you are using LTFT as part of your tuning and you make changes based on them, I always reset the LTFT once I flash the tune to start fresh for the next log.

[ECaulk]

The 2007 ion redline (assuming this is what you're talking about and not a Sky Redline) the ecu has multiple LTFT, not sure on the reset method. If it is a Sky Redline then it should have the Bosch E69 (iirc) ECU with a single global LFTF which you can disable by unplugging the EVAP.

[AP83]

Assuming that this is an Ion Redline, not a Sky, and that you're using the P12 PCM.

1. When the battery cable is disconnected are the LTFTS lost ??

Only if disconnected for a long period, 10 mins or more.

2.When we load a new tune are the LTFTs part of the tune ??

When you flash a tune, the LTFTs should reset. The LTFTs aren't "part of the tune", but the parameters to use them are. It's best practice to reset them using VCM Scanner each and every time you scan the car.

3. How many LTFT values are there ??

Approximately 20, 15 that are RPM/MAP based, as well as idle in gear, idle in park/neutral, ac on/off, and EVAP.

I working on a 2007 Redline

FWIW, on my 2004 Redline, I don't use LTFT's period. Car runs just fine on STFT's, and I don't get random interference with my WOT AFR.

[Super Sky]

Thank you for the replies. My car is a 2007 SKY Redline . I did not even know they made an Ion Redline. I now see they did and it was supercharged. Learn something everyday. So if you have additional thoughts please let me know.

Larry

[cobaltssoverbooster]

reset the trims in the vcm scanner. its fast, easy, and guarantees quality data from the beginning of the recording.

[MikeM173]

LTFT?s lost is nothing on your Sky. We have STFT?s to account for changes, and LTFT?s are just there to ease the amount the ECU has to do on the fly.

1. Yes

2. No

3. LTFT?s are apart of the entire RPM and load ranges.

[Super Sky]

reset the trims in the vcm scanner. its fast, easy, and guarantees quality data from the beginning of the recording.

Cobalt, easier said than done. I looked briefly and did not see a way to clear them. Can you help me out ??

Larry

[MikeM173]

What are you trying to accomplish? Your questions have been answered, so getting more specific will allow us to answer better.

[cobaltssoverbooster]

when connected to the vehicle through the scanner there is a button in the upper header area that looks like a power button. its right next to the check engine light looking button. after the window opens you are now in the override command center for the ecu. Under engine fuel their should be a trim reset....its usually around force trims on/off toggle button.

[Super Sky]

What are you trying to accomplish? Your questions have been answered, so getting more specific will allow us to answer better.

Mike, my question at the moment is "How can I reset the LTFTs" Cobalt said I could reset them with the scanner but I don't see how on mine. I watched the school video on the latest version and I still don't see how on my system. Do you know how to reset them with the scanner??

Thank you, Larry

[Super Sky]

when connected to the vehicle through the scanner there is a button in the upper header area that looks like a power button. its right next to the check engine light looking button. after the window opens you are now in the override command center for the ecu. Under engine fuel their should be a trim reset....its usually around force trims on/off toggle button.

Cobalt, I found and tried that button earlier while scanning and don't believe I got the results you mention. I will try again now and get right back to you. Thanks, larry

[MikeM173]

Larry, I never reset them because I don?t ever have a need to. If I?m tuning, I disable them because then I don?t have to worry about tuning against both LTFT?s and STFT?s. If I?m not tuning, then I?ve tuned it well enough and the computer can now compensate, in which case there is no need to reset LTFT?s anymore. I sold my old car, but I actually deleted the EVAP solenoid and ran it strictly on STFT?s. I don?t recommend that for most cars, but it worked for what I used it for. However, there never really is a need to reset it in my opinion. Just unhook the EVAP and run it on STFT?s, or just drive it long enough (which you should do no matter what), and you will look at both STFT?s and LTFT?s and there would be zero reason to need to start with LTFT?s reset.

Can you elaborate on why you want them reset?

[cobaltssoverbooster]

it happens really quick if the car if running....you click the button when trims are active and it resets to zero then starts trimming within ms.
just click it once after a flash and keep going.

once the trims are within 2-3% its almost pointless at that point because it can trim smoother when the fueling is on point.

[Super Sky]

when connected to the vehicle through the scanner there is a button in the upper header area that looks like a power button. its right next to the check engine light looking button. after the window opens you are now in the override command center for the ecu. Under engine fuel their should be a trim reset....its usually around force trims on/off toggle button.

OK just tried it again. Car running and logging. Clicked the button and got a screen " Controls and special functions". It came up with 2 folders a general folder with a system folder behind it. General folder had 2 options "relink VATS" or "change vin"


Could not click on system folder or close general folder. That was about it

Larry

[Super Sky]

[QUOTE=

Can you elaborate on why you want them reset?[/QUOTE]

Mike, I guess at this point it is more about can they be reset with my version (July 2017) of the scanner than actually the need to reset them. I will just feel better if I can reset them on the fly. I have installed a larger turbo and have been playing wit my A/F ratio and just trying to learn more.

Thank you, Larry.

[MikeM173]

I guess I fail to realize why that would be needed. They are there to lessen the burden of the STFT swings, so resetting them would cause bigger swings for fueling, which isn?t something you want.

I don?t have an answer for you because I?ve never tried it. Sorry.

[cobaltssoverbooster]

ltft skew WOT. resetting them prevents wot from being offset.

[MikeM173]

CSSOB, I?ve never had an issue with it skewing it, but I usually have it dialed in pretty well before I go WOT. I know that doesn?t sound right to most who will read this, but usually my fuel trims are not off much, and I don?t have to worry about LTFT?s. Also if you just disconnect the EVAP solenoid, then there is no concern about them anyways.

[cobaltssoverbooster]

some people dont have issues some do.. its the way i was taught by multiple classes so i consistently roll with it.
i never did it on the lnf because ltft are a single cell which i disable. the other cars have 3d ltft and 3d stft plotting capabilities and sometimes they mess with ve blending.

mike this 2007 isnt a DI E69 ecu its a SC platform.