Duramax Fuel Gauge Calibration after larger tank installation

[hokiebob]

I need some help on my fuel tank calibration. I installed a Titan 52 USG tank and generated a new tank calibration by recording the voltage a % full from a Tech 2 while filling. I've generated the new table and also changed the two tank volume values from 24.62 to 52 on the fuel page (and downloaded), however the gauge calibration isn't correct and the miles to empty is stuck on ~350. I've run ~300 miles and the gauge is still showing full--curious if my float was stuck I hooked up the Tech 2 and its fine and reading 1.8 volts, yet it shows 100% full. In my reading of other forums, ie. EFI Live, there's mention of having to change 3 registers for it to work--so I'm wondering if I've missed something or if the software is missing something. It appears to me that somewhere it still thinks its a 26 gallon tank and since my tank calibration still shows >26 gallons, its going to just "hang out" until I have less than 26 gallons and then it'll work correctly.

Can anyone help me--Bill @ HPTuners-can you verify that the software is writing to the correct registers?

Thanks for any help
bob

[hokiebob]

I should have stated that the vehicle in question is a 2007 LMM Duramax 2500HD. I can post a screen shot of the table I downloaded if anyone things it could be helpful.

[hokiebob]

Attached is a screen shot of the fuel table that I downloaded--note that I didn't do a write entire, only write calibration.

Can anyone see where I may have missed anything. Note, the fuel level reads 1.8V on the Tech 2 and still shows 100% full, so somewhere it still thinks its a 26 gallon tank and is overfull.

[hokiebob]

So here's the latest. If I load the old fuel tank calibration back (or the old curve and change the two tank volume numbers from stock to 52 gallons, it doesn't make a difference), the gauge works ok (still of a bit due to tank geometry differences), but it seems to move off of full and through the range appropriately, however the "miles to empty" are ~1/2 of what it should be. Somehow I'm missing something or what I really suspect, the software is missing writing the tank volume to someplace....so I can it one of two ways--with the new curve, the gauge stays pegged full for ~26 gallons, then it moves through the range like it should (the miles to empty will stay pegged for 26 gallons, then work about right), or I can have it this way where the gauge always works but the miles to empty are ~1/2. I know EFI can do this so I suspect HP is missing something (or I'm missing something, which is entirely possible!).

thanks for any help
bob

[srt-hardware]

I have the same issue somewhat, I changed the rear of my 2 tanks to a new size and have just not been able to figure out the proper equation the the truck uses to display fuel info. If I change the tank size then full tanks only show 1/2 on the guage. I have tried many different configurations and finally resolved to using the gas gauge to tell me when I am empty and don't bother believing any other info.

[Captain Morgan]

11 years later.... has anyone been able to solve this mystery? I have changed the Capacity, Primary Capacity and rewritten the Primary Volume table, the gauge works fine, but range to empty is still reading as if it was a 26 gallon tank.