update- it,'s the line on top that says TANK- which direction should the flow go if i put a check valve inline ?? see beliw for problem no check happening:
1990 Trooper 2.8V6.
bigger line on top of charcoal canister, comes down the side of canister. looks like a little inline black plastic valve clips on there. seems like it should be a check valve that only allows air through it one direction I can blow through it both directions. Is that okay?
I can't seem to find an official name for it so I can replace it. Anyone?

Thanks!!

 

Hi
1990 trooper v6,
Pressure test Fail - Evap system during emmissions test. Any common cause i can check?
my vac lines appear pretty good and tight, and spray tests seem to avail no vac leak. but this may be unrelated and dealing with fuel system pressure holding .