My 1996 ford f150 has a 300 v6 engine and dual fuel tanks. The problem im having is when I put fuel into my back tank it somehow flows into the front tank. I have not put fuel into the front tank in a year but it always has plenty of fuel. Also when the fuel tank switch is switched to the front tank the truck will run good for a while then the engine seems to be cutting out (like not getting fuel) so i switch the fuel tank switch to the rear tank and the truck picks right back up and runs great. I will switch back to the front tank and now the truck runs great for a little while then it cuts out again. Also if it is a warm day you can not start the truck with the switch on the front tank, switch it to the back and it will start easily. Also if the truck is warmed up and you shut it off and try to restart it with the switch on the front tank it won't restart. Switch it to the rear tank and it don't matter it will start hot or cold. Another thing when it is cold outside you can start the truck right up on the front tank as long as the truck is not warmed up. Has anyone ever had this problem and what do I need to do

 

so your having problems with the front tank?

 

My truck is having a similar issue. It is somehow pumping the gas from the front tank to the rear. Is there a check valve that has failed?

 

You have a bad Fuel Delivery Module (FDM) in the front tank.

 

I'm having almost identical issues with my truck (300 w/2 tanks) but I think yours is a little farther down death row than mine is. No cross tank filling on mine yet. My vote is for a bad pump in the front tank. The check valves that prevent back flow - which is why your tank keeps filling itself up - are built in to the pump, so the whole unit has to be replaced. I've heard it might simply be the selector switch in the dash, which is a cheap part to replace. I'm planning to replace mine and cross my fingers, but I think it's probably the fuel pump.

 

The check valve is not built into the pump, the check valve is in the Fuel Delivery module the same place the fuel pump is.
An image of the FDM:
http://i54.photobucket.com/albums/g9...yAssembly2.gif
/

 

Kind of a terminology thing here. In addition to referring to it as the fuel delivery module, it is also referenced in manuals as the "modular In Tank Reservoir (ITR) system". I was talking about the entire assembly when I used the word pump.



I know the valve isn't part of the pump, I kind of just generalized because you can't really just buy a check valve (or other pieces of the assembly) and install it....can you? I've been told the housing for the unit isn't intended to be rebuilt and will likely fall apart. That would be a money saver if you could just replace the parts.

 

My 1988 E250 , 351W, dual gas tanks, did the same stalling routine other folks describe. Had to replace 2 fuel pumps, one to rear, one on frame, plus check valve. Now in big trouble because breather tube in rear tank has rusted, and mechanic says no replacement available. Neither Ford nor J C Whitney nor Tanks Inc has o-ring and breather tube.
Am running on front tank only, and this is bound to fail, being same age as the rear one.

The size of gas tank is being debated. One mechanic claims it is 22 gal. Another says it is 12 gal. It measures 33" wide X 23" long X 7 1/4 deep.
I was told it is 12 gallon, and 12 gallons seem to fill it.

J. C Whitney's 22 gallon behind rear acle tank is OK for measurement, but does not have o-ring, and they don't know where to get one!

Anyone know of a supplier?
Appreciate your help!

bsdetectr@aol.com

 

There is no breather tube in any of your fuel tanks.
Can tell us a little more of what you are talking about?
Where is it located?

 

bsdectr
The size of gas tank is being debated. One mechanic claims it is 22 gal. Another says it is 12 gal. It measures 33" wide X 23" long X 7 1/4 deep.
I was told it is 12 gallon, and 12 gallons seem to fill it.

J. C Whitney's 22 gallon behind rear acle tank is OK for measurement, but does not have o-ring, and they don't know where to get one!

Check out lmctruck.com I don't know about the vans but the 89 and my 95 have 19 gallon tanks front and rear. By saying breather tubs are you talking about the filler necks that have the extra tube in them that lets the air escape when you filling the tank. If the trucks are the same I have two.

 

That tube just has a hose on it with hose clamps. No "O" rings.