Any thoughts on reviving a half-lazy tank selector valve?

[madpogue]

Truck is an '85, the PO told me it only worked on the front tank. Stooopid me didn't ask for more detail. Did some poking today, and determined that the selector switches from front to rear just fine. But when you flip to the front tank, it won't switch until you whack the valve lightly with a hammer. You can actually hear it kick when you hit it.

Any thoughts on reviving it, getting it to work both ways? It's not an electrical problem upstream; the 12V +/- polarity thing works just fine, and the dash switch is good. And when it selects the right tank, it runs fine off that tank and picks the correct tank for the gauge. It's just a matter of switching rear-to-front.

 

[BDCarrillo]

Flush it out. Bits of the showerhead pickups can jam it up.

 

[madpogue]

How do you suggest flushing it? Compressed air in the engine side ports?

I _think_ my showerheads are good; It ran on the rear tank with just a gallon of fuel in it, and I've run the front tank below 1/4. 'Course, maybe the PO took care of the showerheads, but didn't do anything with the valve.

 

[BDCarrillo]

I'd remove it and use carb cleaner through every hole followed by air.

 

[madpogue]

Roger that; will report back results.

 

[madpogue]

Update - cleaned it out, it shot the carb cleaner through the appropriate ports. Plugged in the electrical connector with the ports disconnected, threw the switch several times, and it switched back and forth faithfully. Reconnected the lines, bolted it up, fired up the truck, and it switched a couple of times, but then went back to only switching to the rear tank on its own. It only switches to the front tank when I tap it, just like before.

So hmm, maybe there is something foreign in the rear tank that, when I run on it for a while, is mucking it up. Either that, or it switches easily and freely when there's no "load" of fuel on it, but when it's filled with fuel, it only works the one way. I hope it's the latter; not looking forward to dropping the rear tank. I would think if it were anything in the rear tank/like gumming it up, it would also not run properly on the rear tank. But it does.

 

[BDCarrillo]

Solenoid sticking under fuel suction/flow loading perhaps.... Maybe check voltage when switching, if it's a weak connection the tapping may be helping it connect. If full juice flows for both settings, it's likely a mechanical fault.

Are you running an electric pump with excess flow/pressure?

Not sure on success rate for disassembly and repair... replacement may be in order.

 

[madpogue]

I've got full 12V at the connector with the switch in both positions (polarity reversed, of course). Mechanical lift pump is stock, as is pretty-much the whole truck.

Thoughts about this product? http://www.amazon.com/Standard-Motor-Products-FV5T-Selector/dp/B0049UCF82/ - Connector is another $12-ish.

 

[BDCarrillo]

Price seems good... why swap connectors? If yours pins out fine for voltage (wonder if amperage is the issue??) and isn't corroded might as well reuse it.

Might try giving it a straight shot of 12v to rule out any wiring/weak contact issues.

 

[madpogue]

Connector is a different shape, and I'd have to check about the pinout order.

Hmm, good idea about the 12V straight shot. The dash switch opens/closes contacts for both conductors, so a connection issue is a def. possibility.

 

[gandalf]

I've got full 12V at the connector with the switch in both positions (polarity reversed, of course). Mechanical lift pump is stock, as is pretty-much the whole truck.

Thoughts about this product? http://www.amazon.com/Standard-Motor-Products-FV5T-Selector/dp/B0049UCF82/ - Connector is another $12-ish.

If you decide to go with the selector on Amazon, be aware that it has only a two star rating (out of a possible five). The single review on that selector written on Amazon was not too positive.

Also, if you change the connector, cut off the Ford connector and replace it with one to match a non-standard selector, it's hard to go back to an original. I'd check your local Pick-n-Pull before to did that.

 

[madpogue]

I saw that review. Now I'm leaning toward the Pollak 42-159; gets good reviews on other sites.

 

[OLDBULL8]

Pollak was the original supplier of the FSV, it has the special fuel line connections for Ford. They are available from Ford dealer only for around $260. The FSV from Amazon will work, it the same as the Ford FSV except the fuel line connections and possibly the mounting angle, the wiring connection plug is also different and has to be purchased and changed. Check AZone and others for this same FSV from Amazon, they stock them in store.
I wrote a thread a long time ago on how to take the FSV apart and clean it.

 

[madpogue]

The FSV from Amazon will work, it the same as the Ford FSV except the fuel line connections and possibly the mounting angle, the wiring connection plug is also different and has to be purchased and changed.

Yeah, looks like every aftermarket FSV has both front and rear tank ports facing downward, whereas the OEM has the front ports facing downard and the rear ports facing aft. I'm a little concerned about that; wondering if the rear lines will reach the downard-facing ports on any aftermarket valve.

I still don't think mine needs cleaning. It doesn't hesitate at all when I tap it; flips right over. And front-to-rear is always a good flip. It does seem more an electrical issue, since it consistently works better in one direction than the other. I still haven't tried the direct 12V test; think I'll just try that with some jumper wires and a jump box.

Other odd thing I found was, the hairpin clips on the lines going forward were both gone. The lines still fit snug onto the ports, and I have no air intrusion / running issues. Dumb luck, I know, and a new set of clips from Advance is on my list. Just kind of surprised that I'm not getting air, or not just blowing those lines right off the valve.

 

[gandalf]

Those clips which hold the line to the FSV are Dorman 800-015. That's what I've used on my '92 truck.