Diesel Data: Automotive Repair

Refueling Vapor Cut Valve: Testing and Inspection




EVAP Vent Shut Float Test

Special Tools Required

- Vacuum Pump/Gauge, 0-30 inHg Snap-on YA4000A or equivalent, commercially available

1. Make sure the fuel tank is less than half full.

2. Remove the fuel fill cap to relieve fuel tank pressure, then reinstall the cap.

3. Remove the left rear wheel.

4. Remove the fuel pipe cover.






5. Disconnect the fuel tank vapor recirculation tube (A), and connect a vacuum pump/gauge, 0-30 in.Hg, to the tube.






6. Apply vacuum to the fuel tank vapor recirculation tube.

- If the valve holds the vacuum pressure, replace the fuel tank vapor recirculation tube.
- If the valve does not hold the vacuum pressure, go to step 7.

7. Reconnect the fuel tank vapor recirculation tube.

8. Disconnect the fuel vapor hoses (A) and (B).





9. Connect a vacuum pump/gauge, 0-30 in.Hg, (C) to the EVAP vent shut float as shown.

10. Connect a second vacuum pump/gauge, 0-30 in.Hg, (D) to the EVAP vent shut float as shown.

11. Apply vacuum to the EVAP vent shut float with the pump (C), then check the vacuum on the pump (D).

- If the vacuum responds immediately, check for a clogged tube between the EVAP vent shut float and the EVAP canister.
- If the vacuum does not respond immediately, replace the EVAP vent shut float Service and Repair.