I just purchased an LBZ yesterday - it went from full to nearly empty pretty quickly. I filled up with 70 miles left until empty (according to the cluster) but it only held 13 gallons. The only fuel related mod is an AirDog, no tunes yet. Is this normal for a stock truck and something that EFI can fix, or is something else going on? I tried to search on the topic and couldn't get a definitive answer.
LBZ: Fuel Gauge Inaccurate
- Thread starter 2007LBZ
- Start date
Efi Live can help some but there is a section in the tune where the voltage jump from something like 2 volts to 5 volts and you loose a lot of tunable range there.
You can get around this if you are willing to bend the float arm so it stays under this voltage range then you can scale it for the correct level.
You can get around this if you are willing to bend the float arm so it stays under this voltage range then you can scale it for the correct level.
i would read with EFI Live what is says for voltage at the sender in the tank. you may have a sender going bad or the float has a crack
Mines been like that from day one. When mines on E, it only holds 13-15 gallons. Most I've ever got was 17.
This seems to be a common complaint with the LMMs.
Some have replaced the sender with no change, other see little improvement but all seem to hold more then 10 gallons when "empty"
Supposedly GM dit it so when towing you won't run out of fuel looking for a fuel station when the light comes on.
Some have replaced the sender with no change, other see little improvement but all seem to hold more then 10 gallons when "empty"
Supposedly GM dit it so when towing you won't run out of fuel looking for a fuel station when the light comes on.
After replacing my sender with an aftermarket (leaving the original in place) and rescaling the fuel level tables I routinely get 34 gallons in. The most I have put in was 36 but was likely lucky I didn't run out before making it to the station.
I scaled mine so I have about 4 gallons in the tank when the light comes on. Works great for me
I scaled mine so I have about 4 gallons in the tank when the light comes on. Works great for me
I wish I knew how to do that and had a v2 to do so, how hard would it be for my tuner to tackle or just say hell with it and go off gallons used? My gallons used has never been more than 1.5 gallons off.
well thats annoying as hell. my brothers 2010 26 gal tank reads correct. light comes on with 4-5 gal left. mine does the same with 34 gal tank, light comes on with 5 gal left. my truck did get screwed up when i flashed a tune in that had a 26 gal tank setup in for voltage. filled up like you guys are seeing, only took 15 gal when the light came on.
i tried rescaling it myself and it was nowhere near close. had to find a stock 34 gal file and copy it out of there.
Before replacing my sender I tried to rescale the stock one and got it down to about 7 gallons left when empty. If I took it just a little bit more it would jump to 0 gallons and leave me on the side of the road. I suspected my sender was bad but maybe this is how it works for even a new one
To have a tuner do it you would need to log the voltage when filling up. Run the tank down to as low as possible, then tank a reading of the voltage, put on gallon I. And read the voltage again. Keep doing this until full. Send this lot to the tuner and he can adjust the tune
To have a tuner do it you would need to log the voltage when filling up. Run the tank down to as low as possible, then tank a reading of the voltage, put on gallon I. And read the voltage again. Keep doing this until full. Send this lot to the tuner and he can adjust the tune
So just to make sure I'm reading this right, I run it to fumes basically(which I'm fine with, I have a transfer tank) and log, put (1)one gallon in and log again, and repeat every quarter tank until full or log every gallon??
10-4, thanks. I have to fill up tomorrow, I'll get them sent out when I ft back in town and see how it goes.
You dont even need to log it just read the voltage off the display after you add 1gal and write it down. I would think....
I think most of the time its the sending unit unless your truck has been like that since new. Both my 2500s have screwed up fuel gauges. My LBZ worked fine until 4 years ago now if I fill up at 3/4s its only 12gals. On my 08 I can sit and idle and watch my fuel gauge go crazy.
I think that hard part is getting the right sending unit. It sounds like there are a few of them. Im going to order one for my work truck and see if it looks like the right one for the LBZ too. I just hate dropping the tank since lifting the bed is a no go with 2000lbs of tools and fuel in it.
I think most of the time its the sending unit unless your truck has been like that since new. Both my 2500s have screwed up fuel gauges. My LBZ worked fine until 4 years ago now if I fill up at 3/4s its only 12gals. On my 08 I can sit and idle and watch my fuel gauge go crazy.
I think that hard part is getting the right sending unit. It sounds like there are a few of them. Im going to order one for my work truck and see if it looks like the right one for the LBZ too. I just hate dropping the tank since lifting the bed is a no go with 2000lbs of tools and fuel in it.
My 08 dually was like this. I put a used sending unit in it that was the exact same way. Kind of ridiculous to have a 34 gallon tank that says your empty when you have 10+ gallons left.
