Evaporative Emissions System: Testing and Inspection

Fig. 17 Testing The Purge Control System:

PURGE CONTROL SYSTEM INSPECTION

1. Disconnect the red striped vacuum hose from the throttle body and connect a hand vacuum pump to the hose and plug the nipple.
2. While the engine is cold (coolant temperature less than 40 degrees C or 104 degrees F) allow the engine to idle and apply 53 kPa or 15.3 in. Hg of vacuum and verify that vacuum holds.
3. Increase engine speed to 3,000 rpm, apply 53 kPa Hg or 15.3 in. Hg of vacuum and verify that vacuum holds.
4. Allow the engine to warm up (engine coolant temperature greater than 80 degrees C or 176 degrees F).
5. With the engine operating at idle apply 53 kPa Hg or 15.3 in. Hg of vacuum and verify that vacuum holds.
6. Within three minutes of engine start increase engine speed to 3,000 rpm. Attempt to apply vacuum and verify that vacuum leaks.
7. After more than three minutes have elapsed since engine start increase engine speed to 3,000 rpm and apply 53 kPa Hg or 15.3 in. Hg and verify that vacuum is held momentarilly and then leaks.