Evaporative Emissions System: Testing and Inspection

SYSTEM SERVICE

Ensure all vacuum hoses and electrical wires are routed clear of the exhaust manifold to prevent deterioration due to the high temperature. Vacuum hoses should always be a minimum of three inches from the exhaust manifold.
NOTE: Use only fuel resistant hoses when servicing the evaporative control system.

EVAP Canister Purge Solenoid:

CANISTER PURGE SOLENOID TEST

1. Disconnect vacuum hose that is routed from the Canister Purge Solenoid to the throttle body and plug the throttle body nipple.
2. Connect a hand held vacuum pump to the previously mentioned vacuum hose that was disconnected from the throttle body.
3. Ensure that engine coolant temperature is less than 140°F (60°C) and the engine is cold. Start engine and allow to idle.
4. With the hand held vacuum pump, apply 15 in. Hg vacuum and verify that it holds.
5. Increase engine speed to 3000 rpm, check the hand pump and verify that the 15 in. Hg vacuum is still holding.
6. Allow engine to warm up until the coolant temperature is above 158°F (70°C). Increase engine speed to 3000 rpm (within three minutes of starting the vehicle) and try to apply a vacuum with the hand held vacuum pump. Vacuum should not hold.
7. Let engine return to idle and apply 15 in Hg vacuum. Verify that vacuum holds.
8. Allow engine to run longer than 3 minutes and increase speed to 3000 rpm. Apply 15 in. Hg vacuum. Verify that vacuum holds momentarily then bleeds off.
9. Disconnect Purge Solenoid electrical connector, and apply vacuum. Connect two jumper wires to the Purge Solenoid electrical terminals. Connect one from ground to one of the electrical terminals, and another from the battery to the other electrical terminal.
^ A "clicking" noise should be heard as voltage is applied and taken away from the solenoid.
^ Vacuum should hold when voltage is applied, and bleed off when disconnected.

10. Disconnect jumper wires.
11. Measure resistance between Purge Solenoid terminals. See SPECIFICATIONS.
12. If the Purge Solenoid fails any of the previous tests, it is defective and needs to be replaced.



CHARCOAL CANISTER

The charcoal canister is a sealed service-free unit.