Evaporative Emission Control System Testing

Evaporative Emission Control System:

CANISTER AND PURGE VALVE TESTING

1. Apply 0.53 cm/kg (7.5 psi) pressure to the port marked "V.C.". No air should leak past the diaphragm.
2. Apply 380 mmHg (14.96 in.Hg) vacuum to the port marked "PURGE" and maintain vacuum.
3. Vacuum is then gradually applied to the "V.C." port. If the purge control valve begins to open at vacuum between 180-220 mmHg (7.1-8.7 in.Hg), it is functioning normally.
4. Replace canister and purge valve assembly if it fails this test.

CANISTER VISUAL CHECK

1. Replace canister if cracked or otherwise damaged.
2. Replace canister if fuel is leaking from the bottom.
3. If dirty, plugged or damaged, replace filter at bottom of canister.

FUEL VAPOR LINES, FUEL TANK AND FILLER CAP INSPECTION

1. Visually inspect lines and connections for looseness, kinked or collapsed hoses or other damage.
2. Visually inspect fuel tank and filler cap for deformation, cracks or fuel leakage.
3. Repair or replace any components found to be damaged or defective.

Vacuum Switching Valve Testing:

VACUUM SWITCHING VALVE (VSV) TESTING

1. Apply battery voltage to VSV.
2. Check that air does not flow through "X" and "Y."
3. Disconnect power to VSV.
4. Check that air now flows through "X" and "Y."
5. Replace VSV if found defective.

Rollover And Float Valve:

ROLLOVER AND FLOAT VALVE INSPECTION

Check rollover and float valve for fuel leaks, distortion, cracks, dents and orifice clogging. Replace if found defective.

Ventilation Valve Testing:

VENTILATION VALVE TESTING

1. Check that air flows through ports "B" and "C" when no vacuum is applied to port "A."
2. Use a hand pump to apply vacuum (40-45 mmHg) to port "A."
3. Check that air does not flow through ports "B" and "C."
4. Replace ventilation valve if found defective.