Two-Way Valve Test

Fig. 80 Vacuum Testing Two-Way Valve On Vapor Canister:

1. Remove the fuel tank filler cap.
2. Remove the vapor line from the fuel tank and connect a 'T' fitting for a vacuum gauge and vacuum pump as shown in Fig. 80.
3. Slowly apply vacuum while observing the vacuum gauge. Vacuum should stabilize momentarily at 5 to 15 mbar (0.2 to 0.6 in. Hg). If vacuum stabilizes (valve opens) below 5 mbar (0.2 in. g) or above 15 mbar (0.6 in. Hg), replace the valve and re-test.

Fig. 80a Pressure Testing Two-Way Valve On Vapor Canister:

4. Move the vacuum pump hose from the vacuum to the pressure fitting, Fig. 80a.
5. Slowly pressurize the vapor line while watching the gauge. The pressure should stabilize at 25 to 55 mbar (1.0 to 2.2 in Hg).
a. If the pressure momentarily stabilizes (valve opens) at 25 to 55 mbar (1.0 to 2.2 in Hg), the valve is OK.
b. If the valve stabilizes above or below the specified pressure, replace the valve and re-test.