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Two-Way Valve Test

  1. Remove the fuel filler cap.
  2. Remove vapor line from the fuel tank and connect to T-fitting from vacuum gauge and vacuum pump as shown. See Fig 1 .
    Fig 1: Installing Pressure Gauge To EVAP System
    G00107177Courtesy of AMERICAN HONDA MOTOR CO., INC.
  3. Apply vacuum slowly and continuously while watching the gauge.
  4. Vacuum should stabilize momentarily at 0.2-0.6 in. Hg (5-15 mm Hg).
  5. If vacuum stabilizes and the valve opens below 0.2 in. Hg (5 mm Hg) or above 0.6 in. Hg (15 mm Hg), install new valve and retest.
  6. Move vacuum pump hose from vacuum to pressure fitting, and move vacuum gauge hose from vacuum to pressure side as shown. See Fig 2 .
    Fig 2: Installing Pressure Gauge To EVAP Lines
    G00107178Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Slowly pressurize the vapor line while watching the gauge.
  8. Pressure should stabilize at 0.4-1.4 in. Hg (10-35 mm Hg).
  9. If pressure momentarily stabilizes and the valve opens at 0.4-1.4 in. Hg (10-35 mm Hg), the valve is okay.
  10. If pressure stabilizes below 0.4 in. Hg (10 mm Hg) or above 1.4 in. Hg (35 mm Hg), install a new valve and retest.
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