Excessive Fuel Tank Pressure

[95GreenViper]

Hey everyone, I am trying to track down a root cause and fix for a problem I am having.

I have a 95' RT/10, and had noticed the smell of fuel while driving last year. I then noticed that after warming up, fuel would come out of the fuel cap. I purchased a new cap that relieves pressure. Then after a 40 minute drive I could hear loud hissing coming from the cap during idle. I figured the venting was working. Problem was that after shutting the car off, or when I would go to re-fuel, a large amount of air pressure would come out the the tank. So much so that if I unscrewed the cap too quickly then fuel would spill out.

After some research I took the front fascia bumper off and replaced the Evap Purge Solenoid. I also blew some air into the evap line that runs to the fuel tank, and with the fuel cap off I could hear the air entering the tank..so no clog at least on that one line....I did not however check to see of the Evap Cannister was clogged..

Any experience with this type of issue? Any next steps advice before I go taking the front bumper fascia off again..which is a pain? Lol

Thank you for any advice or help

[GTS Dean]

Have you traced the plastic tube that goes from the solenoid to the intake manifold to be sure it isn't obstructed? Are you sure the evap purge solenoid is operating? An engine scanner should confirm whether it is getting switching voltage.

[95GreenViper]

I have not tried that. Since my next step was to remove the front bumper again and test the charcoal cannister, I will also check the evap line from the solenoid to the intake...but I won't be able to try this for a few days probably.

[dave6666]

There should be a pressure relief devise on the tank. I don't think it is individually serviceable although I may be wrong on that. Point is if that was stuck closed it could cause problems. Look at the emissions routing sticker on the car and also that same chapter in the factory service manual. It should detail out all of the components and how they plumb together.