EGR Gas Flow Test

The following procedure should be used to determine if exhaust gas is flowing through the EGR system.

1. Connect a hand vacuum pump to the EGR valve vacuum motor.
2. With engine running at idle speed, slowly apply vacuum.
- Engine speed should begin to drop when applied vacuum reaches 2.0 to 3.5 inches.
- Engine speed may drop quickly or engine may even stall. This indicates that EGR gas is flowing through the system.

If engine speed does not drop off when performing the test, remove both the EGR valve and EGR tube and check for plugged passages. Also, check the intake manifold inlet passage. Clean or replace these components for restoration of proper flow.

If both the EGR Gas Flow Check and System Test are completed satisfactorily, then the EGR system functions normally.