EGR System Check

1. Disconnect the vacuum hose (green) from the EGR valve, and then connect a hand vacuum pump via the Tee-fitting.
2. Start the engine. As described in the chart below, check the vacuum condition when the throttle valve is opened suddenly (revving) during cold and hot engine conditions. If the engine is hot and the vacuum does not rise over 13 kPa (3.9 in Hg), perform the vacuum control valve check and EGR port vacuum check. Then continue to Step 3. If vacuum rises momentarily, proceed to Step 3.
   Fig 1: Connecting Vacuum Pump To EGR System Tee-Fitting

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

When engine is cold 

[Engine coolant temperature: 20°C (68°F) or less] 

Fig 2: Identifying Normal Vacuum Condition (Cold)

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

When engine is hot 

[Engine coolant temperature: 80°C (176°F) or more] 

Fig 3: Identifying Normal Vacuum Condition (Hot)

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

1. 3. Stop the engine. Remove the Tee-fitting and the hand vacuum pump.
2. 4. Connect the hand vacuum pump directly to the EGR valve.
3. 5. Start the engine and run at idle until warm.
4. 6. The engine idling speed should be rough when a vacuum of 27 kPa (7.9 in Hg) or more is applied to the EGR valve.
5. 7. If engine idles rough, EGR passage is open and the system is OK. If engine idle is not rough, the EGR passage and the valve must be checked for restrictions. Perform the EGR valve check. Then repeat the EGR system check.
   Fig 4: View Of Vacuum Pump Connected To EGR System Tee-Fitting

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.