i have an 87 f250 4x4 with the dual tank setup well i just bought the truck,
as is not running, today i got it running for 2 minutes untill it cut out and stalled, so i checked all 3 pumps and they are working fine, then i found the problem, each tank has 2 fuel lines coming from the in tank pumps, then they go to a round black thing where all 4 lines go in and two come out the other end and proceed to the in line pump then the filter, my question is what is that black round thing before the out of tank pump, i tried going to auto zone but they were no help to me,
thx

 

I'm not sure but this may be the solenoid used to switch tanks. Hope you get it running and welcome to FTE! I know someone here will know for sure.

 

It's called a Dual Function Reservoir. As posted previously, it acts like a buffer in case the low pressure in-tank fuel pump does not supply enough fuel to the high pressure fuel pump which is mounted on the two-outlet side of the DFR. It is also a mechanical switching valve between tanks. (You're welcome) One side of the DFR has 2 lines; a fuel supply going to the high pressure pump and then to the fuel pressure regulator then the injectors, and a fuel return line coming back from the fuel pressure regulator (that will return unused fuel back to the tank from which it came). The other side that has 4 lines has a low pressure fuel feed from the front tank and a fuel return to the front tank, a low pressure fuel feed from the rear tank, and a fuel return to the rear tank.

 

thanks man
this is actually the first ford truck i have ever owned, i don't know much about their systems, allways had dodge trucks in the past, i didn't even think of that, now that i know what that is, i'll have it up and running tomorrow,
the 5.0 in it is solid just need that reservoir because it has seased up on me, no fuel coming out of it
once again thanks

 

If it's bolted thru the frame, with 6 fuel lines total, it's the fuel tank selector valve.

 

Fuel tank selector valve