How is this happening?

[Peter Jackson]

George Roffe wrote:
> OK, I'm a monkey when it comes to emissions, but it sounds like the cap is
> not properly relieving built up pressure and that pressure is forcing fuel
> back up into the cannister.

I agree about the cap not working.
The check valve will let vapor by, the fact that there was pressure
seemed to indicate that the check valve might be sticking. But that
would keep vapor out of the evap. I replaced both as a blackbox fix.

Also, the entry point into the tank from the vapor line is on the top of
the tank. There is no liquid fuel that should be entering that vapor
line.:(

What gets me is the relationship to the AC running. Fuel is increased
when the AC is on to help overcome the compressor drag isn't it?
That and the lack of smell unless the engine is running makes me think
it is a liquid fuel delivery problem/leak, but it's not connected to the
evap circuit.

Peter J