Ok so today i put 70 dollars in I had 8th of a tank left i got 17.5 gallons got in the truck fired it up and the gauge read just shy of full. I was thinking has to be something with the floot. Not sure but I thought they have 34 gallon tanks. I getting into the tank soon anyways to put my drawstraw in. But id like to know if anybody else had this promblem. Also my truck had the intank pump conversion done to it

 

most did, i believe some came with a 27 gallon tank but I could be thinking of the gassers too. I'd say something was wrong with your float or sending unit.

 

swb 34 gallon lwb 35 gallon. but these things dont read the bottom of the tank very well my fuel light comes on with over 8 gallons in it. i drained mine when the fuel light came on to pull the tank and it had 8 plus gallons. been like that ever since io bought it. a guy was in the shop the other day for an air dog and pick up install and his fuel light was on and it had almost 7 gallions in it. so i thing its a dodge thing.

 

When my fuel light comes on, I have 2 gallons left, maybe. I could have a different sending unit, but it kinda seems the opposite of what you guys are saying. I can drive 120-160 miles before the fuel gauge starts moving off of its fullest position. If you are in question of your fuel sending unit, and doing a draw straw upgrade, why not do the Vulcan Liberty system? That's the route I would go, and will if my sender fails.

 

im thinking that its the height or the float arm pivot point i think they can be adjusted although im not sure on it, but a lot of them are on different vehicles. but most ive seen still have about 8 gallons in them yours is the first ive heard of turning on that low in the tank. even one of our 07 5.9 tow rigs turns on with 5-6 still in it. everyone ive ever seen turns on at the 1/8 tank mark which is roughly 5-8 gallons depending on tank size.