DR-22C EGR Valve Operation

1. With engine running and EGR valve vacuum line disconnected, connect an auxiliary vacuum supply to the EGR valve.
2. Disconnect idle motor harness connector, then with engine at idle speed, slowly apply vacuum.
3. If engine speed begins to drop when applied vacuum reaches 2 1/2---3 1/2 inches, proceed to step D.
NOTE: The automatic idle speed motor will attempt to compensate for drop in engine speed from EGR, so idle speed drop may only be momentary at lower appllied vacuum level.
4. If engine speed does not drop during step 2, replace EGR/back pressure valve assembly.
NOTE: After valve is removed, make sure supply tube from manifold is not plugged before replacing EGR valve assembly.