89 bronco I Fuel Tank

[Broncopower33]

Live in the communist state of California. Recently did a smog check on the bronco and had a fuel leak on the vent on the gas tank. The vent is located next to the fuel pump, replaced the part and passed my smog.. However I’ve noticed since during this repair my fuel tank has back pressure and when I remove the gas cap there is quite a bit of air that comes out of the tank. What would cause? is the tank not venting properly now? I’ve never experienced this was curious if there is an issue.

 

[sgtsandman]

That is normal if the system is properly sealed. That means the vapor recovery system is working as it should and the gas cap is sealing as it should.