Honey I Shrunk the Gas Tank

[czei]

My fuel pump started to scream all of the time, and since the car has 240K miles on it figured it was just its time to replaced it. Unfortunately I replaced it with a "high flow" model that also made a lot of noise. The reviews said this pump was much louder than stock so I didn't think anything of it.

When I went to refill the tank, though, something weird happened: the gas cap was on so tight I had to destroy it to get it off. I checked the new fuel pump only to discover the top of the gas tank had crumpled so that the top of fuel pump is listing at about 30 degrees rather than being flat.

Apparently air hasn't been getting in the tank as gas is used up, and the greatly increased suction of the more powerful pump caused the top of the gas tank to bend. Driving the car with the gas cap loosened made the fuel pump noise go away, and obviously prevents air pressure from building up, but I would rather not drive that way all of the time.

There are no cracks or leaks in the tank, so my immediate problem is fixing the venting issue. I checked all of the hoses going from the tank to the "charcoal" canister and they're fine. A check of the diagrams of the '93 Legacy L don't show where air gets back into the tank as the gas is consumed.

Any ideas where I should check for a clog? This car is driven almost exclusively in the dirt so I'm assuming something is clogged somewhere.

[Legacy777]

Your fuel cap is broken. It is supposed to relieve vacuum in the tank. Get a new fuel cap and you should be ok.