Evaporative Check Valve: Testing and Inspection

1. Remove the fuel fill cap.




2. Remove the vapor line from the EVAP two way valve on the fuel tank, and connect it to a T4itting from vacuum gauge and vacuum pump as shown.
3. Apply vacuum slowly and continuously while watching the gauge.
The vacuum should stabilize momentarily at 0.7 - 2.0 kPa (5 - 15 mmHg, 0.2 - 0.6 in.Hg).
- If the vacuum stabilizes (valve opens) below 0.7 kPa (5 mmHg, 0.2 in.Hg) or above 2.0 kPa (15 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 as shown.
5. Slowly pressurize the vapor line while watching the gauge.
The pressure should stabilize at 1.3 - 4.7 kPa (0 - 35 mmHg, 0.4 - 1.4 in.Hg).
- If the pressure momentarily stabilizes (valve opens) at 1.3 - 4.7 kPa (10 - 35 mmHg, 0.4 - 1.4 in. Hg), the valve is OK.
- If the pressure stabilizes below 1.3 kPa (10 mmHg, 0.4 in.Hg) or above 4.7 kPa (35 mmHg, 1.4 in.Hg), install a new valve and retest.