Evaporative Emissions System: Testing and Inspection

Evaporative Line Test:

SYSTEM INSPECTION

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

1. Disconnect the ventilation hose from the pipe at the cannister and connect a vacuum pump tester to the pipe.
2. Operate the vacuum pump tester and verify that no vacuum is held.
3. If vacuum is held, check the check-and-cut valve and evaporation pipe for blockage.

Check And Cut Valve Testing:

CHECK AND CUT VALVE

1. Remove the check and cut valve as follows:
a. Raise the rear of the car and support it with stands.
b. Unfasten the clamps and disconnect the evaporative hoses from the check-and-cut valve.
c. Remove the valve.
2. Connect a pressure gauge to the passage from the fuel tank.
3. Blow through the valve from "A", and check to see that it opens at a pressure of 5.39 - 6.87 kPa (0.055 - 0.07 kg/sq cm, 0.78 - 1.00 psi).
4. Remove the pressure gauge, and connect it to the passage to atmosphere.
5. Blow through the valve from "B", and check to see that it opens at a pressure of 0.98 - 4.9 kPa (0.01 - 0.05 kg/sq cm, 0.14 - 0.71 psi).

NOTE: This test should only be performed with the valve held horizontally. Otherwise, the check balls in the valve will close the passages.

Charcoal Canister:

CHARCOAL CANNISTER

Visually check the cannister for leakage or damage.


PURGE CONTROL VALVE

Check Valve:

1. Disconnect the hose (purge valve to oil filler pipe) from the purge control valve.
2. Start the engine and run it at idle.
3. Place a finger over the hose opening and verify that vacuum is not felt.
4. Increase the engine speed to 2,000 rpm; vacuum should be felt.
5. Replace the valve, if necessary.


CHECK VALVE

1. Remove the check valve.

Check Valve:

2. Blow through the check valve from port "A". and check that the air flows from port "B".
3. Blow through the check valve from port "B" and verify that there is no air flow.