System Test

Fig. 57 Testing the purge control valve:

SYSTEM TESTING

1. Disconnect the vacuum hose (red stripe) from the throttle body and connect a manual vacuum pump to the hose.
2. While the engine is cold (coolant temperature less than 60 degrees C or 140 degrees F) verify that when 53 kPa (15 in. Hg) of vacuum is applied while holding the engine at 2,500 rpm that vacuum can be held.
3. Allow the engine to warm up (coolant temperature greater than 70 degrees C or 158 degrees F) and verify that while the engine is idling and the air conditioner switch is on that vacuum leaks.
4. Turn the air conditioning switch off and verify that while the engine continues to idle it is possible to produce 53 kPa (15 in. Hg) of vacuum.
5. Open the throttle until the engine is running at 2,500 rpm and verify that for three minutes vacuum leaks but after three minutes of operation vacuum holds for a short period and then leaks once again.