I just dropped the fuel tank out of my 1990 1.2 litre Micra, and saw a line coming out of the tank that I don't know the purpose of. I recognize the filler tube, breather tube, feed and return, but what's the fifth one? My Haynes manual calls it a "fuel check valve" but doesn't go into any more details. So, what does it do?
![IMG_0450.JPG IMG_0450.JPG](http://data.micra.org.uk/attachments/69/69625-2004fdf1f3e2bc65c6b7830d53071389.jpg)