Component Tests and General Diagnostics

Purge Control System Inspection:

PREPARATION
1. Disconnect the vacuum hose (red stripes) from the throttle body and connect to a vacuum pump (with gauge).
2. Plug the nipple from which the hose is disconnected


ENGINE COLD TEST (Coolant Temperature 40° C (104° F) or less)
1. With engine idling, apply a 375 mm Hg (14.8 in Hg) vacuum.

^ Vacuum should hold.


ENGINE WARM TEST (Coolant Temperature 80° C (176° F) or higher)
1. With engine idling, apply a 375 mm Hg (14.8 in Hg) vacuum.

^ Vacuum should hold.

2. Within 3 minutes of starting engine, run at 3,000 rpm and apply a vacuum.

^ Vacuum should not build or hold.

3. Connect the vacuum hose (red stripes) removed in step 1 to P nipple of the throttle body as before.
4. Disconnect the purge air hose from the air intake hose, and plug the air intake hose. Then connect the hand vacuum pump to the purge air hose.
5. Apply vacuum to a hot engine [coolant temperature 70°C (158°F) or higher] and check to see that vacuum leaks when the engine is raced.