Hot Engine System Test

Fig. 64 Checking For Vacuum To The Purge Control Diaphragm Valve:

NOTE: The engine should be at its normal operating temperature (the cooling fan should cycle on and off at least once).
1. Disconnect the #19 vacuum hose at the purge control valve and connect a vacuum gauge to the hose, Fig. 64.

Fig. 65 Checking Flow Through The Charcoal Canister:

2. Start the engine and warm it up to normal operating temperature.
3. Block the rear wheels and set the parking brake. Raise the front of the car and support with jack stands.
4. Place the shifter in second gear (automatic and manual transmissions).
5. Raise the engine speed to 3500 rpm. Vacuum should be available. If vacuum is not available, check the purge cut-off solenoid valve.
If vacuum is available, disconnect the vacuum gauge and re-connect the hose to the charcoal canister.
6. Remove the fuel tank filler cap.
7. Remove the charcoal canister purge air hose from the frame and connect the hose to a vacuum gauge, Fig. 65.
8. Raise the engine speed to 3500 rpm. Vacuum should be available within one minute.
a. If no vacuum is available, remove the charcoal canister and inspect for signs of damage. Replace canister as necessary.
b. If vacuum is available within one minute, and/or no damage to the canister is found, test the purge valve.