Hey guys, I have an 08 F250 with V10 gasser. It has the 30.5 gallon tank but the low fuel warning seems to be way off. I can get it down to where it shows only 15 miles to empty, which should be less than 2 gallons left in the tank. When I fill up it will take 23-25 gallons. There are no dents in the tank so it should take closer to 28 gallons right? Can the warning sensor be relearned to be more accurate?

 

I have a V10 F250 CC, LB, 4X4. Because it is a LB it came with a 38 gallon tank. The short bed CC came with 28 gallon tank. I never have heard of the 30.5 gallon tank.

 

I thought it was a strange capacity too, but this is exactly how it is listed in the manual.

Fuel capacity (gal)

30.5 gallons with 141.8, 156.2 wheelbase, 38.0 gallons with 137, 158 and 172.4 wheelbase


If thats a typo in the manual and my tank is actually 28 gals. then it would make a lot more sense.

 

There usually is a couple gallons left when it hits "E" That's where the difference is. Ford doesn't mean o miles to empty and you run out, that's just to the point the gauge shows empty....

 

Wonder if you crawled under and look to see if there was a part number or something. Just to look it up somehow. I would think that it would not be a typo but you never know.

 

I may take a 5 gallon jusg and put in the bed then dive till it stops. I know its not good for it but it bothers me.

 

yeah i hear you my lie-o-meter was wayyy off when it was working to.

when i filled up it used to say i have 240 miles till empty and that never happened. 1 time i was down to 6 miles till empty and it filled up 25 gallons your not the only one

 

The manual for my 2005 says 30.5 gal as well. I've never been able to get that much in it though. Maybe the 28gal refers to the "usable" volume?

 

Each time the vehicle is started it calculates the DTE based on the fuel level it sees and the running average. It could be the angle your truck is parked. If the vehicle is facing down a hill, it could show the DTE as having fewer miles then there actually is. If the vehicle is facing up the hill it will show more miles then there actually is. This number doesn't get recalculated until the next time the vehicle is turned off and then restarted.

 

My first long road trip I hauled a jerry can with 4 gallons of diesel in it. Hit the check fuel light at 425 miles, added 4 gallons, made it home for a total of 525 miles just fine. Since it started fine the next morning and didn't ever stall out or buck like it was purging air, I figure I had roughly 3-4 gallons in the bottom after I hit the warning light. That's seems pretty reasonable to me, since in a SD single digit MPGs are a real possibility if you're towing heavy, and if that happens 4 gallons won't always make it to the next town.

And correct me if I'm wrong, but gassers actually need airspace over the fuel in the tank that diesels don't. So the oil burners get to do the harpoon mod and put 32 gallons in what Ford calls a 28/30.5 gallon tank, whereas a gas guy might get stuck with a long vent/fill tube he can't trim down.

 

I have thought about that but I park on a completely level surface at work all day and it still does it. Took it down to 12 miles till empty and was only able to get 27 gallons in it. It must leave a 2-3 gallon margin of error like an earlier post mentioned.

 

My '04 hits "0 miles until empty" and the light comes on way before that, and I STILL can't get more than about 25 gallons in my 29 gallon tank. But here's my theory on that one: the general public (me included) typically run the gas gauge waaay too low before they fill up. Not smart, I know, but I do it anyway. This kills in-tank pumps because the fuel actually keeps them cool, plus running it that low drags all that sediment into the pump, helping kill it. Is it possible, the Ford engineers are using a little psychology to keep you from running your tank too low? If you think you are going to be stranded, wouldn't you fill it earlier? Hey when our Suburban hit the "E" on the gauge, you were gonna be walking! Don't ask how I found that out. But than again, it ain't like that was the only reason you would be walking driving that thing. Anyway, that's my theory on the gas gauge in Ford trucks, and I'd sure like to hear from someone who actually ran his Super Duty out of gas and see if I'm right about how much actual fuel is left when the gauge reads empty.

 

Correct, the gassers need the air space.

 

Why is that? While I know some hydraulic oiling systems used in industries (the CNC machine I run for example) need a little air in the tank to properly function, I can think of plenty of gas vehicles that don't. Motorcycles, lawn mowers, weed-eaters, both my Mustangs, my wife's Corvette are the ones I know full well have no air space in the tank. I have no idea if my truck does, but I'd like to know what the theory is, and how you know if it does or doesn't.

 

Diesels need some space too since the fuel will expand somewhat based on how much it heats up. If you harpoon the tank and fill it up till fuel is in the fill neck, the fuel can expand and overflow out the fill neck (fuel underground is cool, then heats up in tank on a hot day and expands). Its not like this happens all the time, but it could.


A quote from this site http://www.diesel-max.com/ventkitarticle/

"After some research and tips from other members on the forums, I’ve learned that there are some cautions that should go with this modification. Diesel fuel has a thermal expansion rate of .00046 gallons per degree Fahrenheit. Lets say your diesel fuel comes out of the ground at 50 degrees F, and you fill your tank and park your truck in the summer Arizona sun while you go eat lunch. You spend an hour inside and return to your truck where the fuel has had a chance to heat up to 100 degrees. If you put 35 gallons in your tank, and the temp changed 50 degrees, your tank of fuel will expand by .805 gallons. If you don’t burn that fuel off before it warms up, or leave an air space, it will expand and you could possibly have a leak. The walls of the tank itself may expand with the temp change, the sides could bulge outward as the fuel expands, but it might be wise to keep this in mind if you find yourself in the above situation."