LTFT running rich

[Rano90]

I just got my MPVI and started a log on my 2014 Yukon Denali. I noticed it was running rich most of the time LTFT reaching -17.
I added my log here..can anyone advise me what I need to be looking at first?
is it bad O2 sensors or should I go ahead and do a MAS re-calibration.
Appreciate the support.

the car is in stock form fully, except for a muffler delete.

GMC-YukonDenali2014 - Cruise After base tune2.hpl

and this is the current tune on the car
GMC-YukonDenali2014 - Tourque Converter Slip.hpt

And here is the first log I took at stock ECU tune
GMC-YukonDenali2014 - Base Drive.hpl

[edcmat-l1]

What's done to the vehicle? Or are we playing a guessing game?

[Rano90]

What's done to the vehicle? Or are we playing a guessing game?

the car is in stock form fully, except for a muffler delete.

[Alvin]

Looks Ok to me.. Even stock cars aren't 0/0.

Tune away.. Specifically the MAF table would be a good start.

[Rano90]

Looks Ok to me.. Even stock cars aren't 0/0.

Tune away.. Specifically the MAF table would be a good start.

So I shouldn't be worried about the -17 values? I got these even after resetting the LTFTs.

Thanks for the reply.

[2xLS1]

Is it Flex Fuel?

[edcmat-l1]

It's better running in the negatives than positive. If it were adding fuel that would be a sign of lower fuel pressure.

Being off 17% is nothing to worry about. It has to be off a lot more than that before the PCM thinks somethings wrong.

[Rano90]

Is it Flex Fuel?

No, gasoline

[blindsquirrel]

By not posting the tune file you're forcing people to ask things, and those are things you may not fully understand, and so the questions have to be asked multiple times before the real information gets transmitted. But if you post the tune file, we can open it and see if Virtual Flex is still enabled, and then tell you to turn that off and never turn it on again.

[Rano90]

By not posting the tune file you're forcing people to ask things, and those are things you may not fully understand, and so the questions have to be asked multiple times before the real information gets transmitted. But if you post the tune file, we can open it and see if Virtual Flex is still enabled, and then tell you to turn that off and never turn it on again.

Thank you for the response...It's my first time here, appreciate it. This is the current tune on the car.

GMC-YukonDenali2014 - Tourque Converter Slip.hpt

[Rano90]

It's better running in the negatives than positive. If it were adding fuel that would be a sign of lower fuel pressure.

Being off 17% is nothing to worry about. It has to be off a lot more than that before the PCM thinks somethings wrong.

Thank you so much, appreciate the advice.

[blindsquirrel]

Stock except muffler delete and DOD disabled and idle speed adjusted and virtual flex turned off and lots of transmission changes and also some other stuff, is different from a flat statement of 'stock except muffler delete'.

[Rano90]

Stock except muffler delete and DOD disabled and idle speed adjusted and virtual flex turned off and lots of transmission changes and also some other stuff, is different from a flat statement of 'stock except muffler delete'.

Apologies for that, I thought these should not be affecting fueling, As I've seen LTFTs at -17 even with the first drive log I took with stock ECU tune. I'm attaching that log hereGMC-YukonDenali2014 - Base Drive.hpl