Exhaust Gas Recirculation: Testing and Inspection

EGR Modulator Filter:

1. Check And Clean Filter In EGR Vacuum Modulator
(a) Check the filter for contamination or damage.
(b) Using compressed air, clean the filter.

HINT: Install the filter with the coarser surface facing the atmospheric side (outward).

Installing Vacuum Gauge:

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

3. Check Seating Of EGR Valve
Start the engine and check that the engine starts and runs at idle.



4. Check TVV With Cold Engine
(a) The engine coolant temperature should be below 35°C (95°F).
(b) Check that the vacuum gauge indicates zero at 2,500 rpm.



5. Check TVV And EGR Vacuum Modulator With Hot Engine
(a) Warm up the engine.
(b) Check that the vacuum gauge indicates low vacuum at 2,500 rpm.

Checking System Operation:

(c) Disconnect the vacuum hose from the R port of the EGR vacuum modulator and connect the R port directly to the intake manifold with another hose.
(d) Check that the vacuum gauge indicates high vacuum at 3,500 rpm.

HINT: As large amount of EGR gas enters, the engine will misfire slightly.

(e) Remove the vacuum gauge and reconnect the vacuum hoses to the proper locations.

Checking System Operation:

6. Check 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 the proper locations.