IF you guys need selector valves they are available
Some late '80's early 90's Econolines with dual tanks used the same valve
on an '88? that gets tricky, because from what I've seen the '88 uses the
same valve mechanically, but the electrical connector on it is different.
The problems I've had with the valves are that they were either electrically dead
(the motor didn't work)
internal O-ring failure
OR the retainer that holds the three way valve assembly in the housing slips.
Mind you, I've dismantled my valves by taking a moto-tool to the
rivets and replaced the rivets with #6 Machine screws to facilitate
subsequent repairs.
on my own valve I'm using doubled up valve retainers, because
I'm not running the valve to switch the output of low pressure
in tan pumps to feed a frame mounted high pressure pump.
HOW the six port valve actually works...
Inside are TWO "three way" valves.
The valves are actuated by either pushing or pulling on the valve stems
The pushing and pulling is done by a single "Crossbar yoke" that is moved one way or the other by a motor driven leadscrew.
If you have or can get a dead valve I strongly recommend taking one apart, it's a fascinating bit of engineering....
I'm running high pressure pumps inside both tanks and I deleted
the frame mounted pump, so if I don't replace my fuel filter before
it gets clogged my valve will "sneeze" internal parts, usually either
the valve stem O-ring on the high pressure side, but I blew the valve
body retainer once before I switched to doubled up retainers...
EVENTUALLY I'm going to re-plumb things so that the valve
is only switching the return side of the fuel system.
I can do that by using a Tee fitting fed by a pair of check valves
Only one high pressure pump at a time is going to run...
The contacts inside the valve only actually switch which tank unit
fuel level sensor is connected to the guage, the power to the different
in-tank pumps is actually controlled by the tank switch.
As I've said before in other discussions on dual tanks the important thing is not making the pumps work, it's not making the guages work, it's not making the selector valve work.
THE thing is control of the low pressure return fuel...
Imagine driving with two full tanks and having the system directing the return fuel to the "other tank" that's already full..
In technical terms this is called an "uncommanded crossfeed."
and it's literally the most dangerous thing that can happen.
AD