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Is the fdm actually part of the fuel pump or separately replaceable. Also the pump doesn't seem to be working but is fairly new. Are the electronics replaceable or is it the whole pump? '94 f 150 Flare Side. (Just bought it, work was done by previous owner)
The pump is inside the FDM. The FDM may be pried off the hanger and replaced.
If the new pump (FDM) does not work check the selector switch on the dash.
Here is how the previous owner solved the front tank issue on my 94 F250. They just removed the front tank completely. Cut the connectors off the top of the fuel pump.
Filled them with solder or brazed them making them into a plugs.
Seems to work.
Check valves used to be available from Ford. Solved the problem on both my 89 and my 95 F250s, 4/truck and the pumps are still going strong. The 89's approaching 500,000miles. Parts vendors dealing with NLA parts should have these things since they were used in Fords recall. That's when I got mine
To fix the fuel transfer problem you have to replace the fuel delivery module in the front tank, and if you want to run just a rear tank you need to plug both fuel lines at the front tank. Plugs can be fabricated from common bolts that will insert into the fuel lines and be retained buy the factory clips, with this you won't have any leaks and can return the truck to a dual tank system at some point if so desired. You will probably need to at least partially lower the front tank to detatch the fuel lines so you might as well remove the tank if you go that far.. it's often easier to just cut the bolts holding the straps in place.
would the same repair also work on the 97' 7.3 Diesel tanks? what would the most cost effective solution be for reliable rapair or upgrade? i have been giving a lot of consideration to doing a 38 gal rear tank or something of that nature. would replacing both tanks sending units be the long term choice? best aftermarket brand available now?
I just replaced both the fwd tank and fuel tank selector switch on the dash. after maybe 100 miles after the switch replacement and 600 after the fwd tank replacement fuel began to overfill in the front tank.
How would one go about blocking off the front fuel tank for the time being? Would I just need to cut the return and supply lines, add some fuel hose at the end and plug it with a bolt? Would that hold up to the pressure the fuel system is under?
I bought a new 17 gallon front tank with the FDM in it came with straps from autozone for about $180 for my 96 f150. They price matched rock auto's price. It's the same one but Rockauto is only 2 yrs warranty while AZ is lifetime only takes an hour to to put in if you have basic knowledge. Only need a couple wrenches, sockets and the quick disconnect for fords which you can loaner from AZ. My tank a strap broke and was leaking so we didn't use it anymore. It was getting fuel from the rear pump so I just replaced it. Not to mention im not quite ready to give up on the old girl since she runs so good
To fix the fuel transfer problem you have to replace the fuel delivery module in the front tank, and if you want to run just a rear tank you need to plug both fuel lines at the front tank. Plugs can be fabricated from common bolts that will insert into the fuel lines and be retained buy the factory clips, with this you won't have any leaks and can return the truck to a dual tank system at some point if so desired. You will probably need to at least partially lower the front tank to detatch the fuel lines so you might as well remove the tank if you go that far.. it's often easier to just cut the bolts holding the straps in place.
I'm looking to see if I have the same issue. 1991 F350 dually. The rear gas cap has fuel leaking. It seems to happen when warm out, not so much when cold. I believe the front tank is feeding to and overfilling the rear tank. Is this possible on this year? The truck is driven monthly, has VERY few miles. It has been babied since birth.
