The Gasoline Fairy?

I own a 95 Ford F150 that has both forward and rear gas tanks. Now, I normally don’t use the forward tank because the gauge is broken. On road trips I know that I can drive 200 miles on the forward tank, while in the city its pretty much a guessing game. After a recent road trip, the forward tank was left empty, and while I’ve been driving around the city have relied on the rear tank only. A couple weeks went by, and while filling up both tanks for another trip, I was surprised to find that my forward tank was full! Hmmmm… I figured that I had forgotten I filled it up, switched to the forward tank and went my 200 miles before switching again to the rear tank. So today, I decide to fill both tanks up, and walla, the forward tank is full again… so full that its brimming over onto the pavement. So either the gasoline fairy is visiting me at night, or somehow the forward tank is stealing, leeching, siphoning, the rear tanks gas. SO why would this start all of a sudden??

Bad fuel return valve or bad check valve in fuel pump (in forward tank).

This Is Better Than A Hybrid! A Self Filling Fuel Tank!
Don’t try to figure this out or “fix” it. You could become a millionaire!

“So today, I decide to fill both tanks up, and walla, the forward tank is full again.”

Does this happen only in Walla Walla, Washington, or does it also take place when you are in other cities?


Sorry! The devil made me say that.

Ha Ha! Walla Walla… sigh :slight_smile: Thanks Tardis… that’s brilliant… so I’ve noticed my rear fuel pump getting a little louder lately… connected?

Something is wrong with the front pump. when the lines are being pressurized by the rear pump, fuel is getting past the check valve in the front pump and filling the front tank.

OK thanks, that’s a good call… that means two fuel pumps down for Christmas!! I might still have time to change my list for Santa.

Thanks Tardis!

When you switch tanks, the RETURN lines are not being switched…The return flow is all going into the forward tank, even though you switched to the rear tank. Investigate how the return lines are switched.