Component Tests and General Diagnostics

EGR SYSTEM FUNCTIONAL INSPECTION

1. CHECK AND CLEAN FILTER IN EGR VACUUM MODULATOR
(a) Remove the cap and filter.
(b) Check the filter for contamination or damage.
(c) Using compressed air, clean the filter.
(d) Reinstall the filler 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 EGR vacuum modulator.
3. INSPECT SEATING OF EGR VALVE
Check that the engine starts and runs at idle.
4. INSPECT VSV OPERATION WITH COLD ENGINE
(a) The engine coolant temperature should be below 45°C (113°F).
(b) Check that the vacuum gauge indicates zero at 2,500 rpm.

5. INSPECT OPERATION OF VSV AND EGR VACUUM MODULATOR WITH HOT ENGINE
(a) Warm up the engine to above 50°C (122°F).
(b) Check that the vacuum gauge indicates low vacuum at 3,500 rpm.
(c) Disconnect the vacuum hose from port R of the EGR vacuum modulator and connect port R directly to the air intake chamber with another hose.
(d) 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.

6. REMOVE VACUUM GAUGE
Remove the vacuum gauge and reconnect the vacuum hoses to their proper locations.

7. INSPECT EGR VALVE
(a) Apply vacuum directly to the EGR valve with the engine idling.
(b) Check that the engine runs rough or dies.
(c) Reconnect the vacuum hoses to their proper locations.
IF NO PROBLEM IS FOUND DURING THIS INSPECTION, SYSTEM IS NORMAL; OTHERWISE INSPECT EACH PART