Too much pressure in fuel tank

[bigtmoney]

Anyone have any suggestions for too much pressure building up in my gas tank? I have converted to an in tank pump from a TBI monte but didn't convert the tank. I also have a Holly 12-803BP regulator with a return line back to the tank. I try to keep it at least 1/4 full all the time, usually about half a tank.

My problem is whenever I go for a drive 20 or more miles and come home, the tank is super pressurized, I smell gas and have to back off the gas cap to let out the vapor.....not cool.

I've taken off the evap canister and need to know if it's good or not, when I shake it, it sounds like a can of coffee...is this right? I also have a hose from the large nipple on the carb to the carb side of the evap can and line run from the tank side of the evap can back to the vent line on the fuel hanger.

Any ideas why the tank is building up soo much pressure?

 

[GBODYLS3]

my car did the same when it was in stock form with the mechanical fuel pump. i coverted to the monte tbi pump and sender and eliminated the evap can. i just run a piece of hose off the vent tube on the sender and stuck a breather in the hose. no more pressure at all. it doesn't smell like gas when it sits in the garage either. it has something to do with the evap can is all i can figure. i dont know if anybody makes a vented gas cap you could try or not. my tank would build pressure just sitting in the garage.

 

[bigtmoney]

So you have the filter underneath the car then over the axle? I guess I can try that since I'm using a Monte sender as well...

 

[megaladon6]

detach the line from the can to the tank and try to blow air through it. same with the line from the can to the carb. you can also try to pull vacuum on the can.
it's a VERY good idea to keep the EVAP system intact and functional.