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 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 DATA LINK CONNECTOR 1
- Using SST, connect terminals TE1 and E1 of the data link connector 1. SST 09843-18020
5. INSPECT VSV OPERATION WITH COLD ENGINE
- The engine coolant temperature should be below 47 °C (117 °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 53 °C (127 °F).
- Check that the vacuum gauge indicates low vacuum at 2,500 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 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.
9. REMOVE SST FROM DATA LINK CONNECTOR 1. SST 09843-18020
IF NO PROBLEM IS FOUND WITH THIS INSPECTION, SYSTEM IS NORMAL; OTHERWISE INSPECT EACH PART





VSV INSPECTION
1. REMOVE VSV





2. INSPECT VSV
A. Inspect VSV for open circuit
- Using an ohmmeter, check that there is continuity between the terminals.

Resistance: At 20 °C (68°F): 37 - 44 ohm

- If there is no continuity, replace the VSV.





B. Inspect VSV for ground
- Using an ohmmeter, check that there is no continuity between each terminal and the body.
- If there is continuity, replace the VSV.





C. Inspect VSV operation
- Check that air flows from port E to the filter.
- Apply battery voltage across the terminals.





- Check that air flows from port E to port F.
- If operation is not as specified, replace the VSV.
3. REINSTALL VSV








EGR VACUUM MODULATOR INSPECTION
INSPECT EGR VACUUM MODULATOR OPERATION
- Disconnect the vacuum hoses from ports P, Q and R of the EGR vacuum modulator.
- Block ports P and R with your finger.
- Blow air into port Q, and check that the air passes through to the air filter side freely.
- Start the engine, and maintain speed at 2,500 rpm.
- Repeat the above test. Check that there is a strong resistance to air flow.
- Reconnect the vacuum hoses to the proper locations.