85 ford f150 5.8l carbuerated. short bed. i am replacing my tanks with polymer ones....both current sending units are bad. locally parts store say they dont have a listing for that year carbuerated model sending units. i need one for both side and rear tanks. anybody know any other years that might be compatible?

 

Try looking up the sending units for 80-83 and go by tank size if yours is a standard carbed 351 it should have a mechanical fuel pump on the block and I know certain brands don't even make some sending units for our trucks but once you know the tank size I would look to LMC truck for the units and corresponding pig tails to match it

 

thanks, thats what i have been finding. apparently 85 (and maybe 86) were one off years. nobody bothers to make sending units for them. when i got the truck the other week the front tank was off....i am hoping i can figure out how they were wired and plumbed when they get here this weekend...i ended up going with an 84 polymer tank and sending unit that was cast off the same mold as the 85 according to the company(MTS company)

 

The reason why you are having issues was because they started to phase out carbs in 84 and was all fuel rail in 85 and 6. My f150 was a 300i6 that got a 302 swap. And the sending units for the tank are nonexistent unless you go through lmc and dual tanks on our year are confusing to me seeing as I don't have them and my truck doesn't even have the switch to differ between tanks

 

yeah, it seems like 85 was right at the beginning of emissions control and right at the end of carbs. wonder if there is any correlation? i wanted my "new" truck to be carbureted so i can kinda figure that stuff out while it still exists. got tired of paying a few hundred everytime one of the computers in my truck went south. it seems the fuel system is like this: each tank has sending unit. they send to the mechanical fuel pump, which is a 3 port switch. 2 llines in from the tanks, and one line out to carb. the switch is flipped in the cab where a magnet diverts the fuel from one tank or the other(and reads tank level to corresponding tank) seems pretty simple. i hear the selector valve is not a very reliable product. if not working, it seems like the rear tank is the default. it takes the magnet to switch to the front. the selector valves are over 100 bucks!

 

That's when you make the 2nd tank a gravity feed beer keg from your bed

 

One thing I have noticed is the fuel pump on my truck liked to release suction on the fuel and I end up with air in my lines but I'll see how that changes when I get my carb back from the shop

 

Ford started EFI on only the 5.0 in '85 and '86 all others were carb until '87 or so.
If you have the solenoid switching system then rear is the default.
Here is a wiring diagram (from '86 shop manual):
http://img507.imageshack.us/img507/4813/solsel.jpg
Check out the tanks and senders here. http://broncograveyard.com/
The plastic tanks may have a different size opening for the sending unit? I notice there are 2" and a 3 5/8" sizes. My steel tanks have the larger size.
Just because you find a sender that fits the tank however does not mean that it is compatible with the instrument panel gauges. My senders are the 10 Ohm full 73 Ohm empty type ('86).

 

thanks for diagram klricks