Backpressure Transducer EGR System
- Check vacuum hoses for correct routing. Connect a vacuum gauge directly to EGR vacuum source on carburetor. With engine running, open and close throttle quickly to at least 1/2 open position. If gauge reading vacuum is present, EGR vacuum port is open.
- If gauge reading indicates no vacuum is present, EGR vacuum port is plugged or restricted and should be cleaned. Disconnect EGR supply hose from EGR valve. Connect a hand-held vacuum pump to EGR valve. With engine at normal operating temperature, slowly apply 8 in. Hg to EGR valve. EGR valve stem should move to full extent of its travel and engine idle should roughen, RPM should drop or engine stall.