Exhaust Gas Recirculation: Testing and Inspection

EXHAUST GAS RECIRCULATION (EGR) SYSTEM INSPECTION
1. CHECK 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 out to the atmospheric side.

2. INSTALL VACUUM GAUGE.



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

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

4. CONNECT TERMINALS TE1 AND E1.



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

5. INSPECT VSV OPERATION WITH COLD ENGINE.
- The engine coolant temperature should be below 55°C (131°F).
- Check that the vacuum gauge indicates 0.0 in.Hg at 2,800 rpm.



- Check that the EGR pipe is not hot.

6. INSPECT OPERATION OF VSV AND EGR VACUUM MODULATOR WITH HOT ENGINE.
- Warm up the engine to above 80°C (176°F).
- Check that the vacuum gauge indicates low vacuum at 2,800 rpm.



- Disconnect the vacuum hose from 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 3,500 rpm.
HINT: As exhaust gas is increasingly recirculated, the engine will start to misfire.

7. DISCONNECT TERMINALS TE1 AND E1.
- Remove the jumper from the DLC1.

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

9. INSPECT EGR VALVE.



- Apply vacuum directly to the EGR valve with the engine idle.
- Check that the engine runs rough or dies.
- Reconnect the vacuum hoses to their proper locations.

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