Evaporative Emission 2-Way Valve Test
- Remove fuel filler cap. Remove vapor hose from EVAP 2-way valve. Connect "T" fitting, vacuum pump and vacuum gauge to disconnected EVAP 2-way valve hose. See Fig 1
. Apply vacuum slowly and continuously while observing gauge. If vacuum stabilizes momentarily at 0.2-0.6 in. Hg, go to next step. If vacuum does not stabilize momentarily at less than 0.2 in. Hg or more than 0.6 in. Hg, replace EVAP 2-way valve and retest.
- Move vacuum hose from vacuum fitting to pressure fitting on pump. Switch "T" fitting vacuum hose to pressure hose on gauge. Slowly pressurize vapor line while monitoring pressure gauge. If pressure stabilizes momentarily at more than 0.3 in. Hg, EVAP 2-way valve is okay. If pressure does not stabilize at more than 0.3 in. Hg, replace EVAP 2-way valve and retest.
Courtesy of AMERICAN HONDA MOTOR CO., INC.