I have an 05 2500HD 6.6 Diesel. The Vin shows that I should have a 26 gal fuel tank, but the truck will only hold 20 gal when I fill up. I am running the truck down to E. Plus I am only getting 250 mile per tank. Any ideas on what is wrong?
If I had to make an educated guess as to what was going on, I would say that the fuel gauge sender is not being completely honest with you. i.e. when the gauge reads E there is actually 4-5 gallons of gas still in the tank. This is why when you fill up you are only putting about 20 gallons in.
Also when filling up if you don't pump slow the fuel foams up and shuts the pump off. If you take your time and pump it slowly after the pump kicks off you can almost pump another 2 gallons of fuel in these trucks to top them off. It's not something that you want to do though if you lack patience.
Long beds have 34 and the others have 26. I saw this question on another forum and someone said that it is marked on the bottom of the tank. Mine takes about 22 gallons when it reads empty and thats filling it all the way up to the cap.
I would guess that GM doesn't want you running your tank dry. It would cause them allot of complaints from the customer that doesn’t understand that a diesel injection system cannot function with air in the system and must be bled. Your supplement owner’s manual shows you how to bleed the system, but I doubt many have even cracked the cover on it. In all it keeps everyone sane.
Swap out the OEM tank for the Titan 52 Gallon OEM tank and then get a 100 gallon Combo Tank with Transfer Flow and drive till you drop. I have about a 3000 mile range. Drive back and forth from Montgomery, Texas to Pinedale, Wyoming every month. Never buy fuel up the, too expensive.