Greetings all, new member here. Can anyone confirm or deny that the attached Evap Canister was designed to hold or not hold pressure from the evaporation tube coming from the fuel tank?

 

its not sealed so it can't hold pressure. the bottom is a filter that lets fresh air come in or exit. air passes...hydrocarbons are held in the carbon until they are sucked into the manifold.

all canisters have a fresh air supply...if they didn't they would collapse under vacuum.

 

tech2, Is the fresh air supply a "one way" (flow in / no flow out) port via the vent tube. This particular unit (as installed on my 88 truck) doesn't appear to have an inlet or filter at the bottom of the housing.

 

I'm pretty sure it's meant to vent both ways.
When the tank gets hot the vapors expand and need someplace to go.

 

let's say the charcoal canister is in need of replacement.
1/ are there DTC codes that would indicate a canister so bad it's in need of replacement ?
2/ does a bad canister make it harder for the incoming air from the fuel tank ventilation pipe to pass through the carbon granules and be purged out ?
3/ could a clogged canister cause purge valve DTC's ?

apologies for my questions, but my Chilton's is not much help on when a canister or purge valve may be in need of replacement.

 

@MitchM
These would be excellent questions to ask in your own evap topic, instead of hijacking this unrelated question. I think your 2010 system works a little differently than this 1988 one. OBD was pretty rudimentary back then. Thanks.