I've developed a fuel leak, and a pressurized fuel tank it seems!

[8v-of-fury]

I developed a fuel leak last year with too much fuel in the tank, or if she was parked nose down.. Just figured it was the sending unit gasket and I was going to get to it this year.

HOWEVER, when I got it out of storage with the same low amount of non leaking fuel from the fall.. i went for a burn and when parked on level ground it was leaking.. and the gas cap was whistling. what the hell? When I loosened the cap the leaking stopped. This still has the fuel filter with a return line, and that is about the only way I could see the fuel tank becoming pressurized? Is the cap supposed to be relieving pressure? or wouldn't it all just relieve through the charcoal canister?

 

[SRTMirada]

I would suspect a blockage in the vent line that connects the charcoal canister to the rollover valve.

 

[prowler]

Rollover valve would be a good place to look. I doubt the gas cap. There's a carb vent line that goes to the charcoal canister. Find the line on the top of the canister labeled tank. You should be able to blow through it back towards tank. There's also a return line on the fuel filter that needs to be clear. I know when they do an emission check they clamp the vent line at the canister going back to the tank and pressure up the tank from a special cap they put in place. You didn't say where the leak was from. There are only three lines as far as I know at the tank. 1. fuel line to carb 2. fuel filter return vent line 3. return line from charcoal canister. There is ONE other valve that supposed to be at the front on the supply line to the carb, somewhere underneath door area. I think it has to do with the car getting into a front end accident. The rollover valve depending on model can be at the tank or up front as well. My reference is from my 77 LeBaron, BUT,.... things may have changed as the models years went by.