It appears the fuel pump went out on my front tank and now that I am making trips across country hauling horses I thought it might be time to upgrade the fuel capacity so i can pass a gas station or 2. I have a crew cab with a 2 foot gap before my Flatbed starts that I had mounted a tool box. I am thinking of putting in a 125 gallon tank from a Semi. Has anyone done this? I plan on leaving the Rear Tank Intact as a back up as I dont think I will be able to get an acurate fuel sending unit. So if I run out I will have the rear tank in reserve. My plan is to mount the tank with a universal 45 psi inline pump that is activated when the fuel selector switch in the truck is switched to the front tank. Does anyone know what issues I might run into or have any suggestions? I have seen it done on diesel not gassers and was wondering why.

 

Something to remember, 125 gallons of gas weighs about 900lbs.

 

Are you thinking for mounting purposes or overall weight? As I get 10mpg running around empty or hauling 17,000 pounds of hay I dont think it will effect fuel consumption much. I was going to mount a cradle right on the frame where the tool box is presently.

 

Overall weight mostly. You're right, though. It won't make much difference to that 460. (I have 3!)

 

You need more than a 45 PSI supply pressure. The regulator on the fuel rail sets the pressure at the injectors. You will also need a shut-off valve to the add-on tank when trying to run the rear tank. In a factory dual tank system each Fuel Delivery Module has a valve inside to prevent the running pump from back flowing into the powered off pump.

 

OK I thought on a 1995 the fuel pressure was supposed to be around 35. And the fuel diverter switch did the job of back flow I better look at that a little closer.

 

The fuel pump in these trucks are capable of 100+ PSI of greater into a dead head. The fuel switch on the dash is strictly electrical, pump and sender switching.

A diagram of the inner workings of a Fuel Delivery Module:


courtesy of Subford

 

another thing to remember is that in most states anything over 100 gallons in an auxiliary tank requires a haz-mat endorsement on a CDL.

 

Maybe modify a stock FDM to fit the new tank, with a longer float arm and a longer fuel pickup...

 

That might work I just figured since I had to replace the fuel pump I might as well just straight plum the new tank. I could just drop the existing tank replace the pump and hook the auxiliary tank upmtomthe filler and use a small low velocity transfer pump to fill the tank as I go down the road.

 

http://www.ebay.com/itm/NEW-FUEL-PUMP-MODULE-WITH-INSTALLATION-KIT-STRAINER-FORD-VEHICLES-GA1200MN-/380991680419?fits=Year%3A1995%7CMake%3AFord%7CMode l%3AF-350&hash=item58b4dfafa3:g:Rg0AAMXQxU5SAqgM&vxp=mtr has anyone tried one of these. Seems like a pretty cheap price. Kinda thinking of the switch to transfer fuel route.