Evaporative Emissions System: Testing and Inspection

Testing The Purge Control System:

PURGE CONTROL SYSTEM TEST


COLD ENGINE TEST - Coolant temperature below 60°C (140°F)

1. Disconnect the red striped vacuum hose from the throttle body and connect it to a hand vacuum pump.
2. Plug the nipple from which the hose was removed.
3. With the engine idling, apply 15.7" vacuum.
Vacuum should NOT leak.
4. Increase the rpm to 3000, apply 15.7" vacuum.
Vacuum should NOT leak.

WARM ENGINE TEST - Coolant temperature above 70°C (158°F)

1. Disconnect the red striped vacuum hose from the throttle body and connect it to a hand vacuum pump.
2. Plug the nipple from which the hose was removed.
3. Increase rpm to 3000 within three minutes of engine start-up. Try applying vacuum.
Vacuum should leak.
4. Decrease engine rpm to idle, apply 15.7" vacuum.
Vacuum should NOT leak.
5. Increase rpm to 3000 after three minutes have elapsed from engine start-up. Apply 15.7" vacuum.
Vacuum will be maintained momentarily, after which it will leak.

NOTE: Vacuum will leak continuously if altitude is higher than 7,200 ft. (2,200 m) or if the intake air temperature is higher than 122°F (50°C).

Testing The Purge Control Vacuum Supply:

PURGE PORT VACUUM SUPPLY CHECK

NOTE: This test should be done first, when the Purge Control Solenoid is suspected to be faulty.

With the engine stopped.
1. Disconnect the vacuum hose from the throttle body purge hose nipple.
2. Connect a hand vacuum pump to the nipple.
3. Start the engine and note the vacuum reading.
4. Increase the engine speed sharply and note the vacuum reading.
Vacuum should remain fairly constant through out the test.
If there is no vacuum, the throttle body port may be clogged and will need to be cleaned.



PURGE CONTROL SOLENOID VALVE

NOTE: When disconnecting vacuum hoses, label or mark them to ensure proper routing when reconnecting.

1. Disconnect the red striped vacuum hose from the solenoid valve.
2. Disconnect the electrical harness connector from the solenoid valve.

Purge Control Solenoid Valve Vacuum Test:

3. Connect a hand vacuum pump to the red striped hose nipple.
4. Connect jumper wire leads to the purge control solenoid terminals.
5. Apply a vacuum to the solenoid valve. Vacuum should NOT leak.

Purge Control Solenoid Valve Voltage Test:

6. While vacuum is being applied, apply voltage directly to solenoid. Vacuum should leak.

Purge Control Solenoid Valve Resistance Check:

7. Measure the resistance between the terminals of the solenoid valve.
Refer to SPECIFICATIONS.

Check Valve Testing:

OVERFILL LIMITER/TWO-WAY VALVE

1. Remove overfill limiter/two-way valve from the vapor line.
2. Connect a hand vacuum pump to the inlet side.
3. Apply vacuum. Vacuum should NOT leak.
4. Repeat the test for the other side of the valve.
5. Vacuum should LEAK.