Alfa 75 running rich

[Alfamania]

My Alfa 75 3.0 V6 is the first Alfa ive had so not sure if they run a little on the rich side. Since they have a Bosch l-jetronic analogue fuel injection, it is a very primitive system. What happens is, when the windows are closed its all good. But as soon as I open a window I can smell a bit off exhaust fumes. This happens when i drive the car and when i am stationary.

I should mention that when the car idles in my driveway and i am standing outside, i cant smell fumes and its all fine so not sure whats happening here. I've even checked the boot rubber seal as i though that maybe fumes come in from the exhaust pipe but the seal rubber looks fine. I even replaced the air flow meter with a 2.5v6 one and same story, running rich. Has anyone had the same problem with a Bosch L-jetronic car? thanks guys 

[Alfamania]

Could it be something to do with the Charcoal Canister system being blocked?

[shiny_car]

Have a read of this topic on alfabb.com (bearing in mind their LHD cars): http://www.alfabb.com/bb/forums/milano-75-1985-1993/150149-fuel-smell.html#post740740

Your smell may be coming from the engine bay.

[Alfamania]

I fixed it  It was the one way breather valve which is located in the boot with the fuel tank. I noticed every time I was filling up petrol i was getting pressure and would push out the filler cap when opening. Now the fuel vapour system is circulating properly and no exhaust fumes