Here is the description of the two way valve. As you see it operates when the fuel tank pressure builds and then it opens. You can remove yours and hook up a handle held vacuum pump and see if it opens. Also, you should be able to have it build a vacuum before it opens. If when pumping it doesn't build any pressure then it is stuck open.
Have you pinpointed where this leak is coming from? The reason I ask, is the two way valve just vents the vapor to the canister and not to the atmosphere. So if you have an issue with this valve then you may have fuel in the canister and if that is the case then you need to replace that as well.
Tuesday, July 23rd, 2019 AT 6:59 PM