Evaporative Emissions System: Testing and Inspection

SYSTEM INSPECTION

Evaporative Emission Control System:

NOTE: Check condition of wiring harness and/or vacuum lines and connectors before checking sensors or switches.

1. Warm engine to operating temperature.
2. Run at idle.
3. Disconnect canister vacuum hose from solenoid valve and verify that no vacuum is felt at valve.
4. If not as specified, check valve.

CHARCOAL CANISTER
Visually inspect canister for signs of damage or cracks. Replace if necessary.

PURGE CONTROL SOLENOID VALVE

Fig. 146 Solenoid Test:

1. Disconnect vacuum hoses from valve.
2. Verify that no air can pass through.
3. Disconnect valve connector and connect 12V and a ground to valve terminals.
4. Verify that air can pass through.
5. If not as specified, replace valve.

TWO-WAY CHECK VALVE

2-Way Check Valve:

1. Remove valve.
2. Connect vacuum pump to valve at "a".
3. Check that valve opens at (does not hold more than) 1.46 inHg (37 mmHg).
4. Disconnect vacuum pump from "a" and connect to "b".
5. Check that valve opens at (does not hold more than) 1.73 inHg (44 mmHg).
6. Replace valve if not as specified.

CHECK AND CUT VALVE

Check And Cut Valve Testing:

1. Remove valve.
2. Connect a pressure gauge to passage from fuel tank.
3. Blow through valve from "A", and check that it opens at pressure of 0.92 - 1.20 psi (6.38 - 8.34 kPa, 0.065 - 0.085 kg/sq cm).
4. Remove pressure gauge and connect to passage to atmosphere.
5. Blow through valve from "B" and check that it opens at pressure of 0.14 - 0.71 psi (0.98 - 4.9 kPa, 0.01 - 0.05 kg/sq cm).

NOTE: Perform test with valve held horizontally. Otherwise, check balls in valve will close passages.

FUEL VAPOR SEPARATOR

Fig. 119 Separator Inspection:

1. Locate separator in rear wheel well.
2. Remove separator.
3. Visually check for any signs of damage.
4. Replace if necessary.