Exhaust Gas RECIRCULATION (EGR) System Test
NOTE:
EGR systems contain different components depending on application. See Fig 1. When testing EGR system and components, use proper illustration to determine component location.
NOTE:
When performing EGR system test, it will be necessary to monitor engine RPM by using tachometer or scan tester depending on model application. For tachometer or scan tester connections, see IDLE SPEED & MIXTURE in the ADJUSTMENTS - 2.7L
article.
- Ensure EGR vacuum modulator filter(s) are clean and in good condition. Clean filter(s) with compressed air (if necessary).NOTE: EGR vacuum modulator filter(s) must be installed with coarse side facing upward, away from EGR vacuum modulator.
- Using "T" connector, install vacuum gauge in line with vacuum hose on top of EGR valve. Start engine. Ensure engine runs idles smoothly to ensure proper seating of EGR valve.NOTE: The EGR system components can be checked with engine coolant temperature less than minimum temperature and engine at specified engine RPM.
- Operate engine with engine coolant temp. less than minimum temperature and at specified RPM. See the EGR TESTING SPECIFICATIONS table. No vacuum reading should be obtained.
- Warm engine to normal operating temperature. Operate engine at specified engine RPM again. See EGR TESTING SPECIFICATIONS table. Ensure a low vacuum reading is now obtained.
- To check EGR valve operation, remove and plug hose at EGR valve. Using vacuum pump, apply vacuum directly to EGR valve with engine idling. Engine should run rough or stall. If EGR system does not operate as described, each individual component should be tested.
EGR TESTING SPECIFICATIONS
| Application | Minimum Temperature | Engine RPM |
|---|---|---|
| 2.7L | 140°F (60°C) | 3000 |