Hi All,
apoligies in advance for a longish post/question

1985 carbureted 460 w/ hot fuel, 2 tanks, auto, 4wd, and factory 4V carb.
Truck ran fine (but will occassionally stall for no reason--sometimes starts right up, sometimes cranks forever). Been driving it a lot recently, and all seemed fine. Drove about 25 miles each way to the beach on Friday w/ a load of wood for bonfire, all was great. Saturday morning it started right up first bump and after about a minute or so died and wouldn't start. Cranked and cranked, fired on ether, but that was it. checked front bowl and it was completely empty. I searched the posts and threads here and see that others have issues, but not quite the same one with no fuel.
Here is what I have so far:

• truck has fuel in both tanks
• intertia switch not tripped and power there (Even though I believe this and the oil pressure switch shenanigans is bypassed on initial cranking)
• checked all fuses in the fuse panel under driver's side dash --good
• blue fusible link is on the "I" terminal of the starter solenoid (the one on the fender)
  • traced that wire all the way to the fuel pump cutoff relay...looks fine--I replaced the relay with a new one anyway
• cranked the truck with fuel off of carb...no fuel coming out...
• switched tanks and cranked...no fuel coming out of fuel hose--
• put my hand on the fuel selector valve and had someone switch tanks on the dash....there is physical and audible indication that the valve is working
• I put 12 volts from the battery straight to the blue fusible link (w/ the pink/black wire that I believe is the bypass fuel pump wire) and I can hear the pumps run (or at least a noise/hum) but no fuel comes out of the fuel hose....switched tanks with same result...hum but no fuel

I am stumped...
I feel like it is a simple electrical type issue, but electrical stuff makes me nervous and it was working fine --albeit intermittently at times.

perhaps there is a physical blockage? seems weird that both tanks would have this, but I guess it could be downstream of both tanks...or in the vapor separator/hot fuel device?
Is there a fuse I don't know about? Maybe I will take off the gas caps and see what happens.
Gotta be something simple....hopefully

Any info or help is appreciated...
Thanks

 

If you jumper the relay do the pumps run?
(by pass the the relay with a jumper)

 

Thanks for the help. How would I jumper the relay? What would that tell me? ......asking cause I don't know, not to be cynical : )

FYI--no difference with gas caps off, tried to unscrew the hot fuel return line set up using a couple of tubing wrenches, and it wouldn't budge. traced the fuel lines back to the tanks, but can't see much without dropping the tanks...Also couldn't find any loose grounds, but not sure where I would be looking...

Still my gut tells me it is something simple....front tank reads about half full but maybe there isn't enough fuel in the tanks? I don't really want to add gas if I need to drop the tanks soon after.
Like I said, I am baffled...if I can hear the pumps and there is no fuel coming out....what gives?
Thanks again

 

I seem to remember you jump the fuel pump relay to ground at the OBD connector, something easy like that.

Here's a pinout:

 

 

Look over at the starter solenoid on the pass side fender. You should have a blue wire coming off the "I" terminal. Jump this terminal to the battery + and see if the pumps run.

 

Thanks. I have jumped powered the blue wire fuel pump bypass wire on the starter solenoid and can hear the pumps run...(one at a time, depending upon the orientation of the switch in the dash) just not getting any fuel...from either one.

I suspect it is something to do with the 6 port switching valve...stuck or clogged up maybe? When I pull off the rear fuel line from the switching valve...it pours gasoline out, so I don't think there is a clog/issue from the tank (rear at least) to the switching valve.

 

Fuel hose goes by id. The plastic line Ford used goes by OD. I think one is 3/8 od and the return is 5/16 OD. You can pinch the lines off to try and lessen the mess, pull the proper lines off from one of the tanks and hook them up direct to the lines going to the front to the engine and see if it will run like that. Hose clamps have worked for me, just don't over tighten them.

 

E5TZ-9189-B .. Fuel Tank Selector Valve - 6 ports / Marked: E57B-9F271-BA or E67B-9F271-AA / Available from Ford

1985 E250/350 & F250/350 6.9L diesel // 1985/86 E250/350 & F250/350 I-6 & V8 (gas) over 8,500 lbs. GVWR / 1986 E150/250 302.

This valve has been a notorious POS since day one!

 

Thanks ND for confirming the part #
I have now tried one more thing...compressed air. I push some air lightly from the carb end (through the vapor/hot fuel device) and tried to listen at the tank but nothing was going through.....with dash switch in either position/both tanks....Also tried it from the tank end using a rag to block off most of the filler I pushed air into the tank(s) and waited for fuel to come out of the fuel hose...no dice.....even after switching tanks and all of that. I could hear the tanks "popping" a little so air was going in under pressure. All I got was a headache from the fuel fumes blowing back out of the filler hole when I removed the rag. Makes me think a restriction may indeed be in the switching valve.....still weird that no air or anything would creep through on either tank.

I do have the original 6 port valve (I replaced it --I think unnecessarily about 15 years ago--which is why I kept it wrapped in a rag in my garage cabinet for so long). Does anyone know how I might test it? I can blow through it in its current state, but that is just one tank. A new one is ~$300 and if the spare I have still works it will make my day. I need to drop the tanks anyway but...

Thanks for any help or thinking with this....feel like I am kind of narrowing it down.....maybe

 

New question:

I removed the front fuel tank yesterday, and set it on the ground under the truck. The fuel lines are disconnected from the pump/sender, however the electrical harness/plug is still plugged in. I surmised that I could power the pump (using the blue bypass wire at the starter solenoid deal) and have fuel pour out...at least it would tell me if the pump was good, since I could previously hear them run when powered, but no fuel came out.

I powered the pump and could hear it, but no fuel.....alas I am a doofus and it was set to the rear pump. Switched tanks to front, but now the front pump doesn't work..

My question is---does the tank need to be grounded to the chassis somehow or is that done through the electrical connection to the pump/sender? Pump made noise/worked before, all I did was drop it onto the ground still plugged in. (potentially removing a ground for the pump?)

Thanks for any help

FYI a new ford 6 port switching valve is on the way, since that is what I originally figured might be the issue

 

Your circuit is on page 97 in this link.

Fuel Tank Selector & Gauges - Gary's Garagemahal (the Bullnose bible)

If you look in the diagram, the ground is located at G701

If you go to page 100 in the link, if you look in the list, G701 is listed as behind the IP , RH side of the radio. So the ground for the pumps is bolted up under the dash behind the radio.

 

Thanks all, been out of town for a week.
Here is where I am now:
With front tank out and pump removed, all looked OK except the mesh strainer disintegrated when I removed the pump. Powered the pump via the wiring harness and got nothing, but could hear a "hum" like the pump was trying. Set the pump lightly in the tank and submerged in fuel...tried power again...no fuel, but humming again. Pulled pump out and set it on its side (on top of the tank) had my kid come out and listen....then the front pump made all kinds of noise when powered now and clearly was trying to pump. Tried again and no go...but a hum again....after some listening at the rear tank with cap removed now it was the rear pump "humming"....even though the dash switch was on front! . Went inside cause I was frustrated by this voodoo and it was over 100 degrees....

Later this evening I fiddled with the switch in the dash...up down up down up down...tried to acccess it but cant figure out how to get access to the rear of the switch. Removed the center portion of the dash and radio, as well as removed the glovebox, and still struggling to access the back of the switch...The good news is that in my fiddling, I discovered that the grounds are good, and the front pump now worked when put in the fuel and powered....it pumps like a ****...and then when i switched to the back tank...and powered it from the bypass wire again...I heard humming, but now it filled the carb bowl. (I heard it going in as the bowl was previously dry, and confirmed it by checking the bowl level screw and fuel now sloshed out) like everything was fixed .....Sooooo, I think it is related to the dash switch that selects the tanks (is that possible?) and/or the tank selecting valve...I want to replace both. (already received the expensive switching valve)
Here are my questions r.e. the dash switch: How do I access it to clean/replace it? seems easy but..., How many pins do I likely have, 5? I see the 5 pin is available still...is there another option?. Again truck is 1985 f250HD w/460, hot fuel, and all of the return lines etc.

Thanks again for whatever suggestions you all can provide, I appreciate it

 

You should be able to pull the bezel off around the radio, pull the radio, and then pull the HVAC controls out. The switch comes with them if I remember correctly.

The dash switch in your case had two jobs; It switches power for the pumps by switching the pump power itself, or telling a relay that switches the pump power, they had two different versions. It's other job is to switch the valve on the frame.

The valve on the frame has two jobs, it switches the actual fuel lines, but it also has an electrical switch inside it, and it is what switches the sending units. The valve is actually more related to a electric window motor, the motor moves around in there moving a spool for the fluid lines, and moving a switching section also for the sending units.

 

See it is common for switches to "go bad" from not being used.
The contacts inside get a film and don't make good connections.
Turn signal switches a known for this.

Sometimes moving the switch back & forth a bunch of time can fix it for a bit. Think that is what yours did.
Doing that and spraying with contact cleaner may help also.

Pictured are 2 HVAC panels the one on the right has a duel tank switch to the left of that panel.
The right side of each panel is the blower fan switch.

My switch does the valve on the frame and the gauge unlike yours that does the relays & valve.
IIRC there are 2 different switches because of that so if looking for one just beaware of that.
I have not tested my duel tank switch yet as my truck is still being built.
Thing is the truck I pulled the switch, wiring, valve & tanks from may of only been using 1 tank as only 1 had fuel in it so I will see when the time comes.
Dave ----