What's going on with my LTFT's?

[BrandonHall10]

Spent more time dialing in my VE table the usual way;

Failed maf, disabled DFCO, set OL & CL EQ ratio to 1 between 140? and 230? ECT, disabled STFT, disabled LTFT, disabled CL by setting IAT temp to 285?, disabled COT, copied the high octane spark table to the low octane spark table. (See VE_Calibration_Tune). Drove a few times for a half hour each time. Residential, rural and expressway logging the AFR error using a wideband. Things were looking pretty good. (See 1-14_3_Scan). Copied the data from the AFR Error graph and pasted by % half into my "VE_Calibration_Tune" one last time and saved the file.

I then opened my regular tune (See Daily_Driving_Tune), and pasted the VE table from my "VE_Calibration_Tune" into my regular tune. Here's where things get confusing to me...

As soon as I fire up the truck with the new tune/VE table, the LTFT's at idle go to around -8. In fact, the LTFT's are all over the place while driving. Shouldn't they be closer to zero after working the VE table? Or am I doing something wrong?


Pertinent data:
Stock 2002 LQ4 in an S10
Shorty headers
Cold(ish) air intake

[5FDP]

Have you reset the fuel trims prior to tuning in open loop and after you've gone back to your closed loop tune? I also remove the MAF channels from my logs to prevent possible data skewing from channels I don't need there.

I mean if you got the long term trims to within 3-5% of zero mostly all the time I'd say it's doing okay.

Not to nit pick the VE but clicking that smooth selection a few more times does help even out the little dips and bumps that are kinda there.

[BrandonHall10]

Have you reset the fuel trims prior to tuning in open loop and after you've gone back to your closed loop tune?

I did not. In either scenario. I didn't think I'd need to reset them for my VE/OL scan since I have LTFT's disabled in the VE/OL tune. Not the case I suppose?

I can see why I should have reset then when I flashed the Daily driving tune. Wasn't even thinking about it. Noted for the future.

I also remove the MAF channels from my logs to prevent possible data skewing from channels I don't need there.

I will do this as well.

I mean if you got the long term trims to within 3-5% of zero mostly all the time I'd say it's doing okay.

I think I'd be happy with that as well, but 8%-10% seemed a little out of range. I'll do some more driving making sure I reset the LTFT's, and maybe even force LTFT learn off using the "Vehicle control & Special functions" control.

Not to nit pick the VE but clicking that smooth selection a few more times does help even out the little dips and bumps that are kinda there.

Not at all. I appreciate any input feedback.

[anniversaryss]

Not to steal the thread but What is the purpose of setting the eq ratios to 1 at 140 to 230. Is that bc it's the operating range and setting it to stoich to asjust for the 02s later on? Also the colder temps need richer fuel so you don't mess with that yet?
Thanks
Also I would look into resetting the LTFT as stated.

[5FDP]

Yeah, most calibrations already set the open loop EQ to stay at stoich above 140 degree coolant temp. Some of the early LS1 cars I've seen will run .96 or even up to 1.03 at operating temp in open loop, so setting it to 1.00 is required when running open loop and using a wideband.

[BrandonHall10]

Not to steal the thread but What is the purpose of setting the eq ratios to 1 at 140 to 230.

From the guide I'm using:

By making those cells 1, your PCM?s stoich value will be the target for fueling. Vehicle needs to at operating temperature before tuning VE table.

Also I would look into resetting the LTFT as stated.

I think not resetting the LTFT's each time is what has me messed up. Going to reset them for sure each time from now on.

Edit: 5FDP beat me to it. Better explanation also.

[novaman996]

How do you reset the LTFT when using the remote data logger or no laptop connected when recording..It seems to keep data from the last log...

[5FDP]

By unhooking the battery for a while or using a hand held scan tool that can reset the trims.