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BACKPRESSURE Variable Transducer EGR System

  1. Check vacuum lines for correct routing. Disconnect and plug EGR valve vacuum hose. Disconnect idle air by-pass valve (EFI only).
  2. Connect vacuum pump to valve. Start engine. Apply 6-10 in. Hg to valve and hold. Engine speed should drop at least 100 RPM or stall. Vacuum should not drop more than 1 in. Hg in 30 seconds.
  3. Reconnect idle air by-pass valve (EFI only). Reconnect EGR vacuum hose. Disconnect backpressure variable transducer vacuum connector. Gently blow into center port of transducer until relief valve closes.
  4. Apply 6-10 in. Hg to transducer bottom port and hold. Transducer should hold vacuum at bottom port when pressure is applied to center port.
  5. Using a "T" fitting, apply 6-10 in. Hg to bottom and top ports of transducer. Transducer should hold vacuum. If system does not respond as indicated, test EGR control system. If testing is required, see appropriate COMPONENT TESTING article in the EMISSION section.
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