LS1B Dual Fuel Tank Help

[Pitufo.Naranja]

I have a 2000 L29 C3500HD that I swapped a 0411 LS1B PCM into a couple of years ago. Truck runs well, but the truck has dual fuel tanks and I have been running off the one tank as my tune doesn't show an option for a second tank. I tried a segment swap, never done one before but the only tune I could find with a second tank was for a 08 Duramax C&C and the Editor doesn't want to let me segment swap different OS's. I found one HPTuners forum where someone says the only LS1B tune with dual tanks is an 03 8.1 C&C truck, but I couldn't find any tune file for that truck.
Does anyone have access to a tune file from a truck with dual tanks that would work, or know of any other way to successfully get the second tank working? Also having a hard time finding a walkthrough for how to segment swap, found lots of YouTube videos on HPTuners, but no help with the EFILive stuff. . . .

Thanks in advance

[nonnieselman]

The 2008 duramax uses a completely different ECM so thats not gonna work.

Here are the only 8.1 truck tunes i can find on my laptop.
You will have to check the VIN's to see what kinda truck they were.

[Pitufo.Naranja]

Thanks for sharing those two tunes, but alas, neither have the dual tank fuel segment unfortunately. I did find an 03 C&C tune with an 8.1, but it won't let me segment swap them giving me an error that says the OS version is different

[ChipsByAl]

Can you post your tune and the one you have "03 C&C tune with an 8.1" It may help.
Al

[Pitufo.Naranja]

Attached is my tune (C3500HD) and two tunes that I can see have dual fuel tanks, but I cannot get either to segment swap, just gives me errors. After looking at my tune, maybe I am goin{g down a rabbit hole that I don't need to , if I set {F0502} Fuel Tank Size to the total with both tanks combined, and set {F0504} Primary Fuel Tank Size to the size of just the secondary tank, maybe it will just work, I am kind of new to this, maybe I just assumed I had to find a different segment and I don't need to. If any of you know any help would be appreciated.2003 C2500 DBW 6.0L 4L80E 12593058.tun2003 Chevrolet Avalanche Truck Automatic L18 8.1 Litre (12579405).tun2000 C3500HD 0411 PCM 202005.ctz

[nonnieselman]

You cant use the 2003 Tune or any segment into your PCM. nothing in them are compatible.

1999-2002 is the "P01" PCM and the 2003-3007 is the "P59" PCM.
You have to stay in your lane so the speak.

So only 1999-2002 tunes are able to be segment swapped between each other if they Operating system is the same.
Same with 2003-2007 but the operating systems still need to be the same even tho that generation of PCM is the same.

I see your using COS 0202005. Sometimes that will give you issues on a segment swap. IF you find a tune with dual tanks it will need to be from a 2002 truck with a OS of 12212156, Then convert that file over to COS 0202005, Then you can do a segment swap.

[ChipsByAl]

The files will at least need to be the same year. Do you have a copy of the original file on the truck before the custom operation system was installed.
Al

[Pitufo.Naranja]

I do not have a copy of the original tune, but nonnieselman is right, it is based off a 12212156, the truck had a black box PCM and was swapped/re-pinned to a 0411. I have been looking for a tune based on the P01 PCM that had the dual tank config, but have not been able to find anything, if anyone knows of one that has the right segment in it that would be awesome. When I get some time this weekend I will try to pin the lift pump and level sensor to the PCM and dump the existing tune in again with F0502 and F0504 edited and see if it takes off and works. I have found a couple of 2002 tunes from the repository that look like they have done exactly that, set F0502 to the total size of both tanks combined, and F504 to just the primary tank size. That gives me a little bit of hope that it may just work without doing too much fiddling. . .

[nonnieselman]

I know your looking for a OE style operation.
but on my 2500hd i have a 45 gallon Aux tank in the bed and i use this wifi timer to control the pump to fill the main tank based off if the truck is hauling a trailer or unloaded.

https://a.co/d/f7piZwP

If im hauling a trailer it gets roughly 10mpg, and if empty it gets 15mpg. So i have a program for each and i can disable it when needed.

It was the easiest/cheapest way i could make it work.