hi all,
i have a 1985 f150, 351w longbed 19gallon side mount tank,

is there a difference anyone might know between the 84' and 85' years that would prevent me from using an 84' instead of 85'.

you can get an 84' for about 60 bucks but an 85' cost like 90.00.

also i have been told what goes wrong with them is the float, has anyone heard that one.

if i fill mine but it reads full for like a day, then goes back to empty and i have to keep up with my mileage to gas ratio....already ran out of gas once and would like to get this fixed.

help, opinions, thanks
john

 

It won't workout as the sender itself is different, the hole in the tank is about 2" vs the nearly 4" for 85. The sender ion the 84 is semi rounded and covered with a metal casing, and the 85 uses a more rectangular plastic housing. 85-9 I believe are the same resistance and setup. You can get one that has injection to work by one of two ways, modify it to be able to draw off the bottom of the tank without the pump, or take the sender unit itself off the injection hanger and transplant it to your hanger.

 

forgot to add.....this is a carburated truck not fuel injected, mechanical fuel pump mounted on the engine, 86' engines were injected with the pump in the tank.

 

I replaced my front sender recently, & the float had rotted & cracked & was flooded with fuel. The previous owner had replaced the rear sender a couple of years earlier but I didn't see what was wrong with that one.

 

It would depend on what you are seeing as to whether the float can be to blame. Always empty or low readings when full indicate float. Readings of full all the time, or a waving needle indicate problems with the resistor in the sender unit itself. The info I gave was considering carbed vehicles, not injected.