I know on the pre-1993 trucks they have the valve resevoir selector between the fuel tanks. (as per "dual tank woes thread") Did Ford replace this setup post 93 with the check valves on top of the tanks? I looked for the resevoir on a relatives 94 with a cross flow problem and it wasn't there. After doing some research on here that is my assumption,but I'd like to make sure it's correct. Thanks. Where you at,Steve83? I know you know!

 

On the 93-96 there is a shuttle valve which is basically a pilot-operated check valve in the fuel delivery module of each tank. When the pump for a given tank is running it opens the shuttle valve and allows fuel to return to that tank. The common failure mode is that the shuttle gets gummed up or crudded up and doesn't close properly when the pump is off. This allows some of the fuel to return to both tanks causing a transfer.

 

Is this in the fuel line coming out of the pump about 4 inches out? that's what i'm seeing.On the outside of the tank,not internally,right?

 

Nope.
The shuttle valve is internal. You have to pull the entire FDM to get at it.

 

huh. ok then. thank you!

 

I'm looking. Is it inside the band aid colored housing of the fuel pump? I'm not seeing anything that looks servicable.

 

The "housing" is the Fuel Delivery Module.
It consists of a pump with a strainer sock, an anti-drainback check valve, the shuttle valve and the level sender. AFAIK the level sender is the only serviceable part in the whole thing. The rest of the FDM has to be replaced as a unit.

 

Gotcha. Except for the "AFAIK" thing. What?

 

standard internet-speak for "As Far As I Know"

 

Ahh! I'm getting smarter by the minute on here. TFETDAIHMTWDGOOTGM- standard internet speak for"thanks for educating the dumb *** in his mid-thirties who doesn't get out of the garage much"

 

All good,all works. Thanks again!

 

For future reference: you don't have to wait for me to post. Just click my signature link in any old post and look for what you need. I have an album called '90-96 Fuel System that shows all this.