Evaporative Check Valve: Testing and Inspection

1. Remove the fuel fill cap.




2. Remove the vapor line from the EVAP two-way valve (A), and connect it to a T-fitting (B) from the vacuum gauge and the vacuum pump as shown.
3. Apply vacuum slowly and continuously while watching the gauge. The vacuum should stabilize momentarily at 0.8-2.1 kPa (6-16 mmHg, 0.2-0.6 in.Hg). If the vacuum stabilizes (valve opens) below 0.8 kPa (6 mmHg, 0.2 in.Hg) or above 2.1 kPa 116 mmHg, 0.6 in.Hg), install a new valve and retest.




4. Move the vacuum pump hose from the vacuum fitting to the pressure fitting, and move the vacuum gauge hose from the vacuum side to the pressure side (A) as shown.
5. Slowly pressurize the vapor line while watching the gauge. The pressure should stabilize momentarily above 1.0 kPa (8 mmHg, 0.3 in.Hg).
- If the pressure momentarily stabilizes (valve opens) above 1.0 kPa 18 mmHg, 0.3 in.Hg), the valve is OK.
- If the pressure stabilizes below 1.0 kPa (8 mmHg, 0.3 in.Hg), install a new valve and retest.