Charcoal Cannister Health Check

[LXCHEV]

Ok, odd question I know.... the below charcoal cannister is from a VR 5 litre Calais. Looking to re-install onto the car. Previous owner had left it in a box of spare parts and the ports were blocked with dirt. I've cleaned them out with wire.... but looking to understand how this works before installing back onto the car. Not sure if I still have further blockages internally or not. And not sure if I can used compressed air on these or not?

First off - the largest port on top called "FUEL TANK" - if I breathe into it, it blows air freely, and is directly connected to the port that comes out the bottom of the unit. Strong, direct air blast. Happy with this one.

But the other two smaller ports "VAC" and "PCV" - when I try to breathe through them, I get nothing. Do they need a vacuum source to work? Is there anyway to test these off the car?

 

[LXCHEV]

Ok folks, if you've ever wondered exactly how these carbon/charcoal cannisters work - have a look at this short Youtube video - what a perfect overview.... I've always looked at these cannisters as being dumb/idle equipment - but that's certainly not the case...

Once an appropriate vacuum is applied to the VAC port, the purge valve opens, drawing fresh air in from the bottom, thus allowing fumes to be drawn into the intake and subsequently burned...

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