My truck just started dying because it wasn't getting any fuel. I assumed the lift pump was shot so I put an electric in, and realized that my lift pump hadn't even been getting fuel. Both tanks have fuel, and the truck won't run on either of them. When the key is on and I press the fuel tank switch, I don't hear the noise the valve makes like I used to anymore, so I'm thinking that's my problem. I've read from searching that most times when these valves go out, they get stuck on one tank or the other, so I'm wondering why mine seems to be completely closed off.

Does this sound like it's the FSV? And if so should I check the wiring for a blown fuse or bad connection before replacing it?

And it looks like I need to drop the front tank to replace the fsv. Is this true?
thanks

 

I was able to replace my FSV without dropping the front tank. It was a pain in the ***, but it can be done. From what I remember there's two bolts that go through the frame rail that you can get to from the outside of the frame rail. Remove those and the whole assembly can be pulled out for hose removal.

But I really doubt that a bad FSV would cause a no fuel condition. I don't believe that it's physically possible for them to block fuel.

Visually check your fuel lines for kinks.

Other things to consider - Sometimes the pickup tubes break. Do you have more than 1/4 tank in both tanks?

 

Or, if there's a big hole in the line somewhere, then the pump is just sucking air. Check for that, too. Perhaps a cracked rubber line near the fsv.

-Matt

 

Yes, there is plenty of fuel in both tanks. It's just wierd how switching the tanks doesn't do jack, which is kinda why I don't think they are switching at all. And I don't think both tanks would have the pickup tube break off at the same time.

 

Ok, I'm pretty damn sure my FSV is shot, But now I've noticed the sound of liquid moving in my front tank when my e pump is on, but the e pump isnt't sucking out anything. It's an Airtex 30 gph 5-9 psi pump that's sitting right about where the stock lift pump was, and I'm wondering if it should be back by the tank down on the framerail to work properly and actually be able to pull the fuel??? although I've seen the same kind of pump mounted like mine before and heard it works.

 

the FSV can fail and block fuel.mine did this when i first got it.i pulled it off and found the open ports and just used those for it to run when i was getting it all ready for the road.then i replaced it latter.
that pump should be placed on the frame rail to push fuel.
if you want one to draw,you should get yourself a Carrier Transicold #30-01108-02SV
either way,you'll want to pull the lift pump and block it off, to avoid a crankcase full of fuel and spun bearings.we can leave those troubles to the 6.4l lol.

links to help:
https://www.ford-trucks.com/forums/1...an-1986-a.html


https://www.ford-trucks.com/forums/9...el-gauges.html
if you just use your truck around town,there's no point in using both tanks.to this day i still haven't fixed my rear sending unit.after buying a FSV and rear tank,all this time lmao.you can just bypass the thing and wire up the front gauge if you want.or whatever.just a suggestion.i wasted $ needlessly really.hurts enough filling up one tank at a time.don't know what i was thinking when i thought two at once would be a good idea haha.

 

Mounted the pump down on the frame right in front of the FSV. It started actually pumping fuel so I hooked it all up and took it for a drive, it died about a mile from my house. It wasn't sucking fuel anymore. Topped off the fuel tank till I could see the fuel in the filler neck, still wouldn't suck fuel. Like I said, I can hear liquid moving in the tank when the pump's running. I guess my pickup tube is either almost gone or clogged???...

 

you'll have to bypass the FSV to find out whats going on there.
i remember blowing through a couple of the ports and rigging the thing up so it flowed through those while i was working on the truck/moving it around etc.it's a pretty basic little bugger.don't let it get the best of ya.unhook the lines and show it who's boss.
messy fun times ahead.

 

Just bypass it all together, they are expensive(384 dollars) and its a dealer only item. I bypassed mine on the 1990 before I sold it. I just connected the two ends of the supply and return lines.

 

Allright...

Well I dropped the tank to see wtf was goin on, dropping a 1/2 ratchet with a deep well socket on my nose in the process, that felt good. To my surprise the tank was damn near empty, and clean, someone musta been in there sometime in the last decade. The sending unit and pickup looked new. And why in the hell was the tank almost empty when I could see fuel in the filler neck last night? I guess maybe a venting problem causing the fuel to not want to flow into the tank, along with all my fuel draining out of my front tank and into the rear? And about how much can I get one of those pollak fsv's for? I hope this is making sense at least somewhat....

 

Makes perfect sense....your fsv is picking up from the front and draining to the rear. Mine did this...getting a new fsv for these trucks from somewhere like napa or oreilly is not gonna happen. Ours is dealership only.

 

Pollak 42-302 42-302P 6 Port Fuel Tank Selector Valve Kit Harness - Gas Diesel | eBay

is the one i used.wiring instructions in the link posted above.
there's no need for ford to be so greedy with such an item.it's far too basic of a device for those outrageous prices.so you need to rig the lines and wires,but both are pretty easy really.

 

Ok, but how come fuel was sitting in the filler neck so it looked like the tank was full when it was actually almost empty?

 

Mine went out a couple months ago and caused the same problem. I bought a NEW one from Green Sales. They deal in Obsolete Ford Parts. Was under $100 with shipping.
http://www.greensalescompany.com/

 

I thought about doing that on mine, but what stopped me was the fact that the two tanks on my '86 F-250 were different sizes: the front was a 19 gallon and the rear a 14 gallon.

If you tie the return lines on two different sized tanks together, one tank is going to fill faster than the other and you'll get overflow.