2-Way Check Valve

2-way check valve is located on top of fuel tank. Note direction of check valve installation. See Fig 1 . Remove check valve. With .59 in. Hg of vacuum applied to port "A" of check valve, air should flow. With 1.7 in. Hg of vacuum applied to port "B" of check valve air should flow. Replace check valve as necessary.

Fig 1: Identifying Two-Way Check Valve

Courtesy of MAZDA MOTORS CORP.