Ok on a couple of other threads I have 'd about this damn black cylinder that has ROCHESTER MADE IN USA written on it.It had been suggested that it was the flame trap,however that turned out to be wrong.
ITS THE CARBON FILTER
Now can someone please explain to me what it does and can I do away with it
940s have these, massive things. Haynes has an explanation.
-Fuel vapour absorbtion from the sealed fuel tank
-Vaccum operated valve opens under load and sucks vapours into the engine.
-tank is basically vented into the engine with this canister as a buffer.
To remove, I suggest joining or closing off the breather system that leads to it, depending on the routing and pipe sharing. Then you need to arrange tank venting which I can't say exactly how to do. In the UK 300s there are 2 pipes that lead to the fuel filler neck and, I think, one that leads to the rear cross brace (open end inside it), seems to be connected to the filler neck via a 1 way valve. The filler end has a small hole that is open to the atmostphere via the unsealed outer part of the cap (sealed part is the narrower O-ring seal).
Anyway thats about as far as I've got with it. You might have a different filler cap/end or something annoying like that.
Now that makes a lot of sense.I remember now that when I removed a white 3 or 4 mm pipe from it it smelled of fuel.I blew down it and asked one of the kids if he could hear bubbles from the tank,he coudn't.But also whilst doing something else at the back of the car I noticed a white 3 or 4 mm pipe pushed into a rubber fuel line.The fuel line was badly perrished.If I fill the tank to the max it leaks,so I put the bad pipe on my to do list.My donor car does not have this carbon filter arrangement so I will see what can be done.I was concerened that it might feck with the injection system but it just seems to be one of those Yankee Doodle ideas to make the world a greener place.Also the donor car does have a different filler cap,I'll check to see if the filler neck is different too.
Thank you ever so much for clearing that one up for me
ITS THE CARBON FILTER 
