Hi I got a 1999 Thor p38 (row spec) which lately petrol smells comes out of it while it’s parked mostly in sunny days cause a problem in the evap system. I’ve noticed today that I got a pipe going from the canister to the engine bay next to the expansion tank and when I asked few people about what it connects to all said that comes on nas spec only. What parts are different between the row spec evap and nas spec evap? And could I just put nas evap on it ? Or return it to how it was or delete evap and put a simple breather ?

I'm not sure how or why the NAS one might be different but the answer might be in RAVE.

From memory the (European spec) canister collects vapours when parked. When running a valve opens and draws the vapours through into the engine where they burn off. If pressure builds too high for any reason there is is a safety valve that vents to atmosphere - sounds like this is what yours is doing. I've never had one out so not sure how easy it is to service, or indeed if there's an electrical connection that is prone to corrosion.

Of course, it might be the rubber hose between the filler-neck and the petrol tank has perished and it is leaking a bit of fuel there and that is what you smell. If you look up behind the wheel-arch liner you can see the pipe.