Hey guys , it's been awhile since I've posted. I was resurrecting an 87 F-350 dump months ago , well.. the 460 with the newer heads and E.F.I manifold base to carb conversion was a success , this engine runs like a top and is extremely responsive to the slightest throttle movement. So , that's water under the bridge..but I still have ( 1 ) ongoing problem... the wiring for the dual tank stuff...what a pain!! The fuel gauge doesn't want to work properly. I went back and forth tracing grounds and making sure that the sending wires were in good shape and it just won't work right. This trucks wiring was BAD to begin with ( someone chopped it ) , but I have fixed all of it but this. So...is it possible and I hope it is , to forget the dual tank stuff and just get the gauge to read for one tank? I have tried lots of stuff and maybe the selector switch is the key? I have even taken a spare selector switch and played with the contacts while the key was on so I could watch the gauge...nothing..mostly it will just go all the way past full or go to empty and stay there. I would like to get this to work for one tank using what is already available in the truck , but if it can't be done I am going to drop the stock wiring all together and put a small aftermarket gauge in the dash in place of the stock one. Thanks in advance!!

 

It's the wirewound in-tank senders.
All Fords of this vintage are notorious for these symptoms.
The solution is to drop the tanks and replace them.

A new gauge won't solve your problem.....

 

Thanks again for the info , I actually used the mid-ship tank and sender from another truck in the front , as for the rear.. it is an above the axle between the frame rails plastic tank , it was already in it. So , if I get a new sending unit I should be able to use only one tank and have it read without messing with both , I just want a tank that tells me the truth and won't leave me along the road somewhere... (again...lol)

 

Well , guess what... I bought a new sending unit and upon removing the old one for the 15th time I noticed something. The brass float was full of fuel!!!! Had a pin hole in it just like another I had did. So , all my wiring work wasn't a complete waste of time.... just had some parts failure going on. I put in the new sending unit anyways.. nice to have a gas gauge that works in this beast. The truck is gonna be almost new when I'm done @ this rate... lol