Exhaust Gas Recirculation: Testing and Inspection

Vacuum Modulator Operation:

Preparation
- Remove vacuum modulator.
- Remove modulator cap and filter.
- Clean modulator filter with compressed air.

EGR System Inspection:

- Using a three way connector, connect a vacuum gauge between EGR and modulator.
- Start and idle engine.


BVSV Operation
- Check that coolant temperature is below 104° F (40° C).
- Raise engine speed to 2,500 rpm and note vacuum gauge.

No vacuum present

- Allow engine to reach normal operating temperature.
- Raise engine speed to 2,500 rpm and note vacuum gauge.

Low vacuum present

Modulator Inspection:

Modulator Operation
- Disconnect vacuum hose from port R of vacuum modulator.
- Using a spare hose, connect manifold vacuum directly to port R.
- Raise engine speed to 3,500 rpm and note vacuum gauge.

High vacuum present

- Restore all vacuum hoses to original postions and remove gauge.
- If any portion of test failed to provide desired results, refer to COMPONENT TESTING.