I just received word from a mechanic that was looking at why my 1994 F-250 (7.5 litre V-8) wouldn't start.

He's telling me that with dual tanks, I have to have gas in both tanks, or the truck won't start and run. (Apparently, my father-in-law ran the back tank dry when he borrowed it.)

Now I may be thinking old school, prior to all of this computerized junk they use these days, but this just isn't computing with my brain.

Why would the truck care whether or not one tank has fuel if you're trying to run the truck off of the other tank and it's full?

Anyone out there know anything about this topic?

Thanks,