Thanks, Bill. I got something similar to that when I first started having problems (oil pressure switch) but the colors didn't match up. Your diagram does. Except for the 351 carb , kingpins and body , my 86 is identical to my 87. reps

 

With my short bed I could unbolt the bed and tilt it over to the passenger side and prop it up with a stout piece of 2x4. Pulling the tailgate off first. My old long bed required a helper. This technique is dependent on how rusty your bed bolts are. When I first did this on my '95 I for some reason had the sense to treat the bolts to some anti-seize. Glad I did as I've had to get back in there twice more.
If you have a tailpipe behind the right rear wheel, it will made a nasty big bend in the bed if you tilt the bed up without lowering the pipe first. My dent was already there when I bought the truck.

 

My 87 does not have the frame pump either as it has a carb. I cleaned out the tank when I had the pump out.

I havent attempted to fix the rear tank yet. I just wanted to get it running and threw emmissons before I put any more money into it. When I switch to the rear tank I dont hear the pump run at all and the fuel guage is pegged full.

The guage on the front tank is working correctly but the pump is not working. I hooked the pump up to a spare battery and its dead. Wiring checks out and I even put a new plug on the harness where it connects to the pump. The last 2 pumps did the exact same thing. The first one lasted a few months of tickering with the carb and test drives but the most recent one lasted a 20 mile drive and it was dead.

 

That's what bothers me 2007, All wiring checks out. Put an Airtex pump in and went on a 170 mile trip.Ran ok except when going up a hill the gauge(rear) went to empty and was erratic the rest of the trip. Filled up tank in PA and gauge read full and worked ok rest of way home.
Did check fuel tank selector switch. Exterior contacts look good, no corrosion or signs of heat.

 

And what did the "headlamp test" on the in-dash switch reveal ??

I'm still leaning towards the in-dash tank selector switch.

Bob

 

Actually, Bob , the draw test on the switch didn't reveal anything- probably because I didn't think to do it......The draw test at the pump connectors showed ok. I'm going to check with local Ford dealer Mon on the switch, if not Blue Oval lists one. Almost "dissected" the switch but figured I'd better have a replacement first.More parts, it will also fit son's 89.

 

"Actually, Bob , the draw test on the switch didn't reveal anything- probably because I didn't think to do it......"


"Almost "dissected" the switch but figured I'd better have a replacement first"
Yep, been down that disastrous road many times.

Keep us posted,

Bob

 

Got a selector switch from Ford dealer. Identical to won in truck. "Dissected" the old one , no indication of any contact problems. I did find that the springs that push on the contact slides seemed a little weak, which might have resulted in a loss of conductivity.

 

I'm having the same issue on my 1986 with a 1987 Pump/sending unit assembly in my F250 with the rear tank. I'm on my second pump from Napa and after a year and 1000 miles it just died again. I keep the rear tank 50% full so I know the fuel pump is not overheating.

Have people had better luck with Airtex pumps rather than the Carter pumps Napa uses?