Fuel Selector Switch....

[Alaskan]

Our 1990 & 1991 B190 E350 Ford vans have fuel injection and two fuel tanks, unlike the future E-series vans that have a single fuel tank. Prior to 1990 this same E350 van was equipped with a carburetor.

By-the-way, the switch at the base of your dash just switches between the tank gauges, it has nothing at all to do with the selector switch...

After 1991 Ford changed to a single fuel tank on the E350 vans and retained the fuel injection..

With fuel injection, due to the pressure required, you will have an access of fuel that needs to be returned to the fuel tank. A carburetor engine does not have a fuel return line.

So, with dual tanks and fuel injection our 1990 & 1991 rigs have a pressure-activated fuel selector switch, rather than electric as found in many other applications. That switch is activated by the pressure of the returning fuel.

This switch controls both the return and supple lines so its rather complicated in what it does.

A frequent problem when this switch stops functioning correctly will be fuel spilling out of a filler from one of the tanks...not a good situation. This occurs when the switch malfunctions returning fuel to the wrong tank, therefore filling it to the point where it can be forced out of the filler/vent.

To replace this switch assembly is costly, but its pretty simple to disassemble and perhaps clean up and get the little valves within it back functioning.



Here in this pictures below you'll see the red-rubberish diaphragm that with pressure activates the valves.....check that carefully for tears or holes



Here in the 3 pictures below you can see the small valves that can become stuck, very possibly from prolonged non-use...





The diaphragm pushes down on the round silver metal disk seen below at right....ANY defect in this diaphragm will cause the selector valve to stop working

[URStruly]

You waited.... ????

[Alaskan]

More behind than usual, days, weeks and perhaps months, but URStruly I got it done....

[micabarry]

Congrats Alaskan for purchasing back your old rig. You confirm what I've always thought of we B190 lovers, we are all nuts!
Anyhow, the fuel selector switch on my 91 is bad and will pump gas out the fill hole of the opposite tank selected unless I switch back and forth, just as you describe. Local Ford dealer wants $300 for the part and another $250 to put it in. I can get it for $199 On-line and I'm nuts enough to try putting it in but do you need a special tool to disconnect Ford fuel lines? And you must have to release the preasure on the lines, right? Since you have done it and when you have a moment free, if that is ever going to be the case anymore with your new project, I'd value your thoughts. Thanks! Barry in Vermont

[Choptop]

Congrats Alaskan for purchasing back your old rig. You confirm what I've always thought of we B190 lovers, we are all nuts!
Anyhow, the fuel selector switch on my 91 is bad and will pump gas out the fill hole of the opposite tank selected unless I switch back and forth, just as you describe. Local Ford dealer wants $300 for the part and another $250 to put it in. I can get it for $199 On-line and I'm nuts enough to try putting it in but do you need a special tool to disconnect Ford fuel lines? And you must have to release the preasure on the lines, right? Since you have done it and when you have a moment free, if that is ever going to be the case anymore with your new project, I'd value your thoughts. Thanks! Barry in Vermont

I would also be interested in this fix and pics, if possible.

[micabarry]

Ok. It may be a while if I decide I can do it because it isn't undriveable and I'm on to sealing windows and repairing bed over cab.

[Abie Sea]

I think I may be having the same problem. My front tank seems to be associated with the stalling after some driving and normally under stress or warm. While the back tank does not over fill when the engine seems fuel starved, It could be this selector valve. I talked to some knowledgeable folks that had several suggestions that might work. The first dealt with a check valve in the back tank that is supposed to block the flow of fuel back. If the switch only controls the senders, does this mean that the pumps are running continuously, even when the tank is empty? Does anyone know how the pumps are controlled?

The other suggestion was that there was debris in the front tank that would clog the filter on the in tank pump. This sounds like it would have some merit. When switched to the back tank and the front tank pump is off, sediment would settle off of the front tank filter.

I would be interested if hearing whether anyone has been able to access the pictures on Alaskan's initial post. They do not seem to allow access from this site. Let me know if you find anything out in your situation.

[Choptop]

On my '90, if the switch at the base of the dash only controls the gauges how come when I was slowing down on the freeway the other day, switching the lever from front to rear, appears to have started the use of the rear tank and I was back in business

[skater]

On my '90, if the switch at the base of the dash only controls the gauges how come when I was slowing down on the freeway the other day, switching the lever from front to rear, appears to have started the use of the rear tank and I was back in business

I don't think Abie Sea meant that it only controls the gauge.

[Choptop]

On my '90, if the switch at the base of the dash only controls the gauges how come when I was slowing down on the freeway the other day, switching the lever from front to rear, appears to have started the use of the rear tank and I was back in business

I don't think Abie Sea meant that it only controls the gauge.

I thought not but...

[micabarry]

I never did fix mine before tucking it away but I did go out and fill both tanks before driving it to storage(about 30 miles) and as long as I kept switching tanks I was able to keep it from overflowing. The switch under the dash does switch tanks through the big control valve (size of a big oil filter) street side in front of generator. My problem started with this valve leaking on a trip. I stopped at a Ford dealer in Gaspe Quebec and they "fixed" it. It stopped leaking but no longer works. If my front tank is empty and rear tank full, after 100 miles running on rear tank I'll have 1/4 tank of gas on the front. And if both tanks are full, in about 30 miles it will start pumping gas out of the filler hole in the opposite tank selected.e As Alaskan points out somewhere these are known to be problematic in Ford vehicles early 90's, and expensive to fix.
As for both tanks running all the time, my sense is that only happens when the rear tank is selected. Rear pump pumps to the front tank and front tank pumps to engine. I believe the rear pump is off when front tank is selected. There are numerous referrals in ths forum to the danger of running the rear tank empty and burning up the pump. But I really don't know if I have that right. I should warn forum readers my wife tells me that I often know just enough to be dangerous.

[Abie Sea]

I was commenting on this note in Alaskan's original post.
"By-the-way, the switch at the base of your dash just switches between the tank gauges, it has nothing at all to do with the selector switch..."
I have had the same experience of switching from the front tank when the engine is stalling. It would seem that there would have to be a switch to turn off the pump in the tank not being used, because if it continued to operate when dry, the pump would burn out. I will be continuing my research

[Choptop]

I see in '91 they went w/a single 35 gal tank, I realize that the 6 or so more gallons given the previous years may get us a few more miles down the road but if a person starts having problems w/the valves controlling the dual tanks, could a person go to one of the newer 35 gallon tanks ?

[Abie Sea]

I have been checking all around the internet to gain more information on this problem. The more likely situation even with the fuel transfer, it that the fuel selector switch is not sending the return flow to the right tank. If this is the case, then there is no need for a check valve in the tank. These are the most informative links. http://www.blackeagle12.net/F150/Dual_T ... ector.html and https://www.youtube.com/watch?v=qBE3LWWmelM . The video was most informative. Hope this helps.

[Choptop]

I have been checking all around the internet to gain more information on this problem. The more likely situation even with the fuel transfer, it that the fuel selector switch is not sending the return flow to the right tank. If this is the case, then there is no need for a check valve in the tank. These are the most informative links. http://www.blackeagle12.net/F150/Dual_T ... ector.html and https://www.youtube.com/watch?v=qBE3LWWmelM . The video was most informative. Hope this helps.

Thanks