2015 Denali 2500 LML tuning question

Gmcnjeepguy

New member
Apr 28, 2025
2
0
1
Alabama
I got my truck already tuned and deleted, its got banks delete under the hood from cold air intake to pipes and everything, CP3 conversion, FASS filter and lift pump, straight pipe dual exhaust which I am not a fan of I would rather have a single 5 inch to axle dump, but it has a 5 position switch, I have been told by the previous owner that he got 29mpg which I know is not right, the truck int lifted with 37's calculated on miles per gallons, I am looking at 11 to 13.5 the computer shows much more, and the average speed when looking at the computer shows 20-30 mpg, it has a throttle controller on it as well, EVC I think is the name of it, but I think it has exlynk tunes in it. I have been told that EFI live is the best tunes by someone in this group with out calling names, but also was told that these LML trucks can't hold 5 tunes and the switch is useless. They said it only has 1 tune and it defuels the other settings when you change and switch and makes the truck run poorly, my question is how do go about finding those other tunes and tuner for it and is it going to actually hold 5 tunes vs defueling like they said it will do? Which I know that the tires are a big issue, I am going to go back to 35 AT when these wear out, I didn't know they would scrub like they do when I got it the stupid thing needed tires and the dealer wouldn't touch it so I put 37;s back on it like an idiot, and the computer was showing and still does 20 plus mpg but I know that is not right. Any help or input I greatly appreciate! Oh I forgot the owner also upgraded the turbo to a stage 1 turbo as well.
 

Lennydmaxguy

Just another diesel tech
Nov 8, 2023
125
65
28
Somewhere, USA :)
Yes, the 5 position knob that you have now is a fuel limiter knob. I don't personally hate them as much as some people do. I've had great experiences using Efilive on these trucks. There is supposed to be a way to make true multi stage tunes for your ECM type, but it would be a custom third party tune, nothing Efilive can do itself.
 

Gmcnjeepguy

New member
Apr 28, 2025
2
0
1
Alabama
Yes, the 5 position knob that you have now is a fuel limiter knob. I don't personally hate them as much as some people do. I've had great experiences using Efilive on these trucks. There is supposed to be a way to make true multi stage tunes for your ECM type, but it would be a custom third party tune, nothing Efilive can do itself.
That is what I wandered, it did have I don’t know if it still does or not but it had ezylink on it but I think the dealer has messed that up honestly, they messed with so much crap and took stuff off the truck when the previous owner treaded it in, I think they may have wiped the tunes and put something in there to get the lights off with, I can’t prove it I don’t guess but something don’t seem right with it compared to what I was used to in my ram I had with efi live and 5 position switch