Why does my BVSV keep breaking on my Supra?

And what effect does it have on the system? I noticed that my fuel economy started getting BETTER, and then a cursory check of the fluid leves revealed the darn thing had broken AGAIN! The last time it broke, we put a screw in the tube to block it, and capped the broken part. This time, it broke without my knowledge. All I know is, 1. Fuel Economy jumped up quite a bit; noticeable, at least (My speedo is not working, but since I usually drive a regular route every day, I noticed it took less to fill the tank than before) and 2. There is a smell of gasoline worse than before (I had been unable to find a filler neck, but with the new tank installed, I can fill it to half without any spilling or orders...now there is a more pronounced smell of gas more often).

A check of the TSRM reveals:

If you look at the diagram, you will see the number (1), pointing to the Check Valve in the charcoal cannister. Follow that line to the BVSV; the broken fitting is at the end of this line, at the BVSV. This is interesting, since, according to the diagram, the flow is FROM the tank, to the cannister, through the BVSV and on to the Throttle Body, where it is marked PURGE. I would have thought the flow would have been BACK to the tank!

So, any ideas on what this does, how I can fix it or eliminate it? This is part of the EVEP Emissions system, so I am presuming the car will not pass it's next inspection in April if I don't do something!