1973-1991 Dual fuel tank systems theory of operation

[Dleslie212]

Originally Posted by hatzie

The charcoal canister isn't a big deal to plumb and it isn't a performance hit.
It's only three connections.

1. a vacuum line from the valve to a ported vacuum source,
2. a tee to the PCV valve for the purge port on the canister
3. a connection to the vents on the tanks

How would a charcoal canister keep gas from spewing out of the tanks?