Fuel Selector Control Valve - (3 hose) - troubleshooting.

[Starliner]

Hi guys
My 84 F250 manual only shows troubleshooting steps for the 6 line selector valve. I dont have return lines on mine so my selector is the simple 3 line one.

When I switch tanks the fuel guage changes to the correct tank but I am getting no actual switching of tanks.
I am tempted to just replace the valve but since there is only 1 wire going to it I should at lease check it if I can.
Any help?
Thanks.

[Gary Lewis]

Your system should be wired as shown below, which is from the 1981 EVTM: Documentation/Electrical/EVTM/1981 EVTM.  I would check to see that the brown/white wire has power on it when in the Rear position.  If so and the valve doesn't switch then the valve must be bad.

[Starliner]

Oh great Gary, that is EXACTLY what I was looking for. 

Thanks very much.

Joe

On Fri, Aug 28, 2020, 10:47 PM Gary Lewis [via Bullnose Enthusiasts] <[hidden email]> wrote:

Your system should be wired as shown below, which is from the 1981 EVTM: Documentation/Electrical/EVTM/1981 EVTM.  I would check to see that the brown/white wire has power on it when in the Rear position.  If so and the valve doesn't switch then the valve must be bad.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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NAML

[ArdWrknTrk]

I'd start by making sure fuse #15 is supplying power to the switch, on the red wire #973.

[FuzzFace2]

ArdWrknTrk wrote

I'd start by making sure fuse #15 is supplying power to the switch, on the red wire #973.

Yep mine popped the fuse a few days ago and I wondered why the front tank level was not going down?

FYI the 3 hose TSV defaults to the rear tank with out power.
So what Gary said of having power on the wire when on rear tank is wrong. THe wire should have power when on front tank.

FYI II when looking for replacement 3 hose TSV look on Amazon as that is where I picked up 2 just in case mine was bad before I found the bad fuse.
I could not find the 3 hose TSV on line at any of the "local" parts stores, only the 6 hose ones.
Dave ----

[Starliner]

Thanks guys.
Good to know the default position.

Turns out the valve is fine .  .  .  SO,
I had already replaced the rear tank sending unit, it was junk.
It turns out there is a clog in the metal fuel line somewhere.
There is definitely a small opening though, maybe like a clogged artery because whenever I disconnect from the valve fuel did pour out.

So now I have gas ALL OVER ME.
I was thinking of trying to blow out the line, alternating ends.  I was also thinking of trying fish tape.  I was also thinking of taking a shower.

[ArdWrknTrk]

I think if the fuel line is corroded internally I'd replace it before it burned my truck down....

When shopping for brake line last week I noticed Amazon has this nickel/copper tube in 3/8".
If I had a choice I think that's the way I'd go.
It's SO easy to form and flare.

[Starliner]

There some varnish at the first bend of the steel line.
I fished out both sides with trimmer line, then blew it all out.
Fixed.
I will keep an eye on the clear filter I put after the valve.
I didnt think it was corrosion because this is the San Diego truck.

Thanks.

[ArdWrknTrk]

I keep forgetting your trucks not from around here, Joe.  

That does look very solid.
Maybe run some fuel treatment like Techron for a few tanks to help dissolve that junk?