Evaporative Emissions System: Testing and Inspection

Canister And Purge Valve Testing:

CANISTER AND PURGE VALVE TESTING

1. With engine "OFF," disconnect hose "A" from the common chamber side and blow into hose. The hose should be free of restrictions and air should flow into the canister.
2. Reconnect hose to common chamber.
3. With engine running at idle, disconnect hose "C." Check that there is no vacuum at "B" and "D."
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:

VACUUM SWITCHING VALVE (VSV) TESTING

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