Fuel Coming out of Filler cap while driving
 

I have an 1989 F250 4x4 5.8L (Gas) with duel tanks. I have had fuel pouring out of the front tank at the filler on 2 occasions while driving. On one occasions I had just filled up, and on the other the front tank was 1/2 full, but I had just filled the rear tank.
I noticed that the fuel tank gauge was dropping disproportionally to the miles driven after filling the rear tank. I suspect that somehow fuel is being pumped from the rear to the front tank. The front gauge showed full when the spillage occurred. Have anyone heard of this happening? What should I be looking at to correct this situation?

Thanks,
-Steve

Hi Steve,
To correct the situation, you need to replace the fuel pump module (fuel pump and gauge unit) in the front tank.
The valving in the module isn't working and is allowing the return line fuel to go to the wrong tank.

hanky, am I wrong in thinking that back in '89 they might have still been using the older style fuel switching valves instead of the seperate pumps? I can't remember clearly; there's been a lot of alcohol between then and now. I'm willing to take a hit on this if I'm wrong...but, I'm sure you'll let me know!

I do remember saying I was pretty sure when it involved an E series , but I wasn't positive when it was an F series and somebody said come on they aren't that much different.
According to the info I have The F series in that year did have the separate pumps, hic !!

I stand corrected. The differences are somewhat minor, but DO exsist. After the last 10 or so years, I really didn't pay attention too much, so there is the possibility that I'm wrong. I'll try to be more attentive in future. Maybe I'll just sit around and try to catalouge everything I've worked on. That should only take another 20 years or so.

From the little bit I was able to learn, you could place two Ford vehicles same model, same year next to one another and they were built differently.
Soooo, my info could be wrong too!