Evaporative Emissions System: Testing and Inspection

1. Check all hoses and fuel tank filler cap, replacing as necessary.
2. Disconnect the vapor vent line connecting carbon canister to vapor/liquid separator, fuel tank, or check valve.
3. Connect a three-way connector, a manometer, and a cock, or an equivalent three-way change cock, to the end of the vent line.
4. Slowly supply fresh air into the vapor vent line through the cock until pressure becomes 15.75 inches H2O.
5. Shut the cock and leave it closed.
6. After 2.5 minutes, measure the height of the liquid in the manometer. Variation of the height should remain within .98 inch H2O on all models.
7. When the fuel filler cap does not close completely the height should drop to zero in a short time.
8. Remove filler cap. If height does not drop to zero in a short time, repair or replace vent hose.