EVAP canister removal question

[goldeninja20]

I removed the evap canister. In the back of the gas tank (filler neck end) there are 2 holes. I know the big one is for the main filler neck where the gas comes in. The smaller one i am using as a vent, I want to put a check valve at the end of this vent, so it will take in air but not let it out. I know the factory has check valves but where are they located? Where are the factory evap lines? Are they metal lines? A diagram would be amazing. I am just looking to get rid of all unused lines, and also maybe find a check valve so there is no need for purchasing a new one.

 

[estoyaqui30]

Here's a factory drawing maybe that will help

 

[goldeninja20]

Having a problem on it leaking when almost full. How many ports are there on the gas tank that may have been left open?