After fighting the fuel system for a few weeks, I realized that the problem was the aftermarket solenoid-style fuel pumps. Because they didn't allow fuel to bleed back into the tanks (like the original impeller-style pumps), the DFR was unable to switch, and it would jam midway, blocking all fuel flow.
Since aftermarket low-pressure impeller pumps cost ~2x as much as solenoids, and we already had new solenoids, I replaced the DFR with these valves from NAPA, and a SFR. There have been no fuel problems since.
The solenoids are carefully plumbed so that, when UNpowered, they default to the same tank. Wiring then is simple: they're parallel to the OTHER tank's pump, meaning, when the pump for the other tank runs, the valves are energized & direct fuel to & from the other tank.
Even though this section is strictly for low-pressure fuel, I still chose to use EFI-rated fuel hose.
For more info, see this album:
...but these have now been replaced with a 6-port valve designed for EFIs:
![fuelsolenoids.jpg After fighting the fuel system for a few weeks, I realized that the problem was the aftermarket solenoid-style fuel pumps. Because they didn't allow fuel to bleed back into the tanks (like the original impeller-style pumps), the DFR was unable to switch, and it would jam midway, blocking all fuel flow.
Since aftermarket low-pressure impeller pumps cost ~2x as much as solenoids, and we already had new solenoids, I replaced the DFR with these valves from NAPA, and a SFR. There have been no fuel problems since.
The solenoids are carefully plumbed so that, when UNpowered, they default to the same tank. Wiring then is simple: they're parallel to the OTHER tank's pump, meaning, when the pump for the other tank runs, the valves are energized & direct fuel to & from the other tank.
Even though this section is strictly for low-pressure fuel, I still chose to use EFI-rated fuel hose.
For more info, see this album:
[url=http://www.supermotors.net/registry/2742/66025-4][img]http://www.supermotors.net/getfile/669591/thumbnail/d03diaphragm.jpg[/img][/url]
...but these have now been replaced with a 6-port valve designed for EFIs:
[url=http://www.supermotors.net/registry/media/858333][img]http://www.supermotors.net/getfile/858333/thumbnail/01olda.jpg[/img][/url]](https://www.supermotors.net/getfile/727253/fullsize/fuelsolenoids.jpg)