Exhaust Gas Recirculation (EGR) System

Fig. 187 Testing the EGR system:

1. Disconnect the vacuum hose (green stripe) from the mixing body and connect a hand vacuum pump to the vacuum hose, Fig. 187.
2. Verify that when the engine is cold [coolant temperature less than 60 degrees C (140 degrees F)] vacuum leaks from the EGR control solenoid valve while the engine idles.
3. Verify that when the engine is warmed up [coolant temperature greater than 95 degrees C (205 degrees F)] vacuum holds at 8 kPa (2.5 in Hg.) while the engine is at idle and holds at 23 kPa (7.0 in Hg.) while the engine stumbles at idle.