Exhaust Gas Recirculation: Testing and Inspection

EGR SYSTEM INSPECTION:
1. INSPECT AND CLEAN FILTER IN EGR VACUUM MODULATOR.



- Remove the cap and filter.
- Check the filter for contamination or damage.
- Using compressed air, clean the filter.
- Reinstall the filter and cap.
HINT: Install the filter with the coarser surface facing the atmospheric side (outward).

2. INSTALL VACUUM GAUGE.



- Using a 3-way connector, connect a vacuum gauge to the hose between the EGR valve and VSV.

3. INSPECT SEATING OF EGR VALVE.
- Start the engine and check that the engine starts and runs at idle.

4. CONNECT TERMINALS TE1 AND E1 OF DLC1.



- Using a jumper wire (or SST 09843-18020), connect terminals TE1 and E1 of the DLC1.

5. INSPECT VSV OPERATION WITH COLD ENGINE.
- The engine coolant temperature should be below 55°C (131°F).
- Check that the vacuum gauge indicates zero at 2,500 rpm.

6. INSPECT OPERATION OF VSV AND EGR VACUUM MODULATOR WITH HOT ENGINE.
- Warm up the engine to above 60°C (140°F).
- Check that the vacuum gauge indicates low vacuum at 2,500 rpm.
- Disconnect the vacuum hose port R of the EGR vacuum modulator and connect port R directly to the intake manifold with another hose.



- Check that the vacuum gauge indicates high vacuum at 2,500 rpm.
HINT: As a large amount of exhaust gas enters, the engine will misfire slightly.

7. REMOVE VACUUM GAUGE.
- Remove the vacuum gauge, and reconnect the vacuum hoses to the proper locations.

8. INSPECT EGR VALVE.



- Apply vacuum directly to the EGR valve with the engine idling.
- Check that the engine runs rough or dies.
- Reconnect the vacuum hoses to the proper locations.
HINT: As exhaust gas is increasingly recirculated the engine will start to misfire.

9. REMOVE JUMPER FROM DLC1.

^ IF NO PROBLEM IS FOUND DURING THIS INSPECTION, SYSTEM IS NORMAL; OTHERWISE INSPECT EACH PART.