Sup guys. So I dropped the rear tank, put a brand new sending unit and pump combo in, replaced both sections of gas line going in/out of the rear pump (they were super kinked), and now I've got an awesome amount of gas shooting out of the supply line (before was a trickle) going into the fuel reservoir. Hooked the lines back up to the fuel supply reservoir and the truck doesn't run. The front pump has been buzzing like it's going out for some time (I've starved it from kinked lines), so I went ahead and ripped the old one out and threw a new Bosch in along with a new fuel filter. Still doesn't run. Pulled the line coming out of the high pressure pump off and it's pushing nothing but air. So I think my problem lies in the fuel supply reservoir. Can you guys maybe explain to me better what this does other than temporary fuel storage? Anything I could've messed up when I blew compressed air through it to clean it out?

 

The DFR (Dual Function Reservoir) has 2 functions, it hydro-mechanically switches supply from either tank depending on which one has pressure and it has a small reservoir which keeps supply flowing to the high pressure pump if the lift pumps loose their supply.

Test pressure for an air supply used for testing purposes should be no more the 5psi.

Here's one:

 

I've only got a single tank, but okay. So, if I put more than 5 psi on it, it'll mess it up?

 

Single function reservoir then.. Its a good possibility... they don't do well with 90psi...

 

....I'd say I put at least 60-70 through it :/

 

I did the same thing when I was troubleshooting my fuel system, put shop air on it so your not the first. I took it apart and tried to make it work, couldn't do it. I bought a new one problem solved.

If you have a solid flow of fuel pissing out of the supply line when the pump is on and with the SFR in there, nothing coming out the front side except maybe a dribble. Something inside that thing is stopping da flow.

 

if you only have a Single tank you do NOT need the reservoir just go to the auto parts store like advance auto parts and get Bypass lines... they are in the help section and there is a pack with a 3/8 and 5/16 lines about 10 to 12 inches long or up to 18 inches...

I was there yesterday and I know they have them

You could just put a high pressure pump in the rear tank from a 95 and get rid of the front pump and only run 1 pump...

why Ford did a low pressure and high pressure pump is beyond me...

 

...wish I would have known that 2 days ago, I wouldn't have bought two new pumps. Can I bypass the valve even with the high/low pressure pump set up?