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System Operational Test

Bring engine to normal operating temperature. Connect a vacuum gauge at distributor advance vacuum hose.

  1. Run engine to 1500 RPM, there should be no vacuum. If vacuum is present, replace SDV valve.
  2. Wait 40 seconds, there should be vacuum. If there is no vacuum, check vacuum source back to carburetor spark port. If vacuum source checks out, replace SDV valve.
  3. Disconnect hose from black side of check valve, there should be vacuum. If there is no vacuum or vacuum drops, replace check valve.
  4. Return to idle and reconnect hose at distributor. Connect gauge to hose at black side of check valve. Turn engine to 2500 RPM, there should be no vacuum. If vacuum is present, replace EGR/PVS valve.
  5. Return to idle and reconnect hose at check valve. Connect gauge to hose at EGR valve. Run engine to 2500 RPM, there should be vacuum. If there is no vacuum, check vacuum source back to carburetor EGR port.
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