hello all,

i have an 85 f-250 6.9L. on my way to work i went up a pretty steep, fairly short, hill and the engine died. i thought it was the fact that i was low on fuel (exactly how low i don't know - my gauge doesn't work accurately) and the remaining fuel shifted to the rear. i coasted it back down to the flat, and cranked it over a couple of times and it caught. i drove around, found a gas station and filled the tank. i drove back to my job, up the same hill, and - it conks out again. i tried again to coast it down to the flat and cranked it over and over and now it's just not starting. i had to leave it parked near my job and i guess i'll need to tow it. wanted to check in with you all and see if anyone had any thoughts/advice as to what the problem might be.
thanks for reading; i appreciate any & all feedback. and thanks for such a great forum. i've been learning a lot about my new old truck reading through all the posts.
may the force be with you.

 

My first guess would be the fuel pickup in your tank. About the time the guage starts acting funny the pickup tube is generally starting to crack from all the years of fuel sloshing around in the tank.
It will start to run out of fuel with less fuel drawn out of the tank every time.

When you filled up do you remember how much fuel you put in to fill it?
With stock tanks it should be about 18 gallons to fill each tank if you were really close to empty.

With the tank full I would pull the bed to change the sending unit. In fact I would pull the bed to work on the sending unit even if the tanks were not full. Do both tanks while you are in there. Dropping the tanks is a royal pain in ...you know what I mean.
Two fuel lines one electrical connection and the fill tube while balancing the tank on your knee while laying under the truck where you can not see will give you plenty of chances to use your four letter vocabulary. The back one is even more fun because you add a skid plate to the list.

Something you may want to check before you do that is the fuel pressure out of the transfer pump. It is much easier to replace than the sending unit/ pickup tube.
It should have about 7 pounds pressure on the line up to the filter from the transfer pump.

Be careful about cranking the engine for very long without long cool off periods between cranking, the starter is expensive and does not like much over 20 seconds of cranking without a good rest.

Also, my 86 runs out of fuel going down a hill long before it runs out going up a hill.