Outer Limits 4x4 Board

Can someone please tell me that exactly the purpose of the carbon canister is?

Because whatever it's meant to do, i dont think its doing it. I've found that pressure is building up in my fuel tank and petrol is being suctioned up and leaking out of the carbon canister, but if i take the tube running to the tank off the canister theres no pressure build up. This leads me to believe the carbon canister has carked it.

So would it be fine if i just put a small filter on the tube that runs to the tank, or even one between the tube from the engine and the tank tube.

It is meant to trap the petrol vapours from the fuel tank that would normally be vented to the atmosphere. These are then purged into the inlet manifold when the car is started.

On most vehicles the purge valve can get stuck and the symptoms you are experiencing can occur. Try replacing the canister and cleaning the purge valve for it. You could also be losing pressure in the tank from a leaky fuel cap, if it gets left for a while (possible side issue).

It won't function correctly if the system is modified, nor will it pass the emissions test without it. In NSW you can expect a canary at you next yearly.