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1978 Models

  1. With engine at normal operating temperature, disconnect Neutral switch (Man. Trans.) or inhibitor switch (Auto. Trans.). Place transmission in Neutral.
  2. Disconnect anti-dieseling solenoid. Connect harness side of connector to a voltmeter and ground the other voltmeter lead. Connect solenoid valve side of connector directly to positive battery terminal.
  3. Disconnect fuel shut-off vacuum switch-to-intake manifold vacuum hose. Install a vacuum "T" fitting in hose, then reconnect hose to switch. Connect vacuum gauge to "T" fitting.
  4. Start and run engine. Increase engine speed to 2500-3000 RPM, quickly close throttle, and note vacuum gauge and voltmeter readings. Vacuum should rise quickly to at least 24 in. Hg as throttle is closed. Voltage readings should vary as shown in illustration. See Fig 1.
  5. If pressure is lower (higher) than specified, remove rubber cap from fuel shut-off vacuum switch and turn adjusting nut clockwise (counterclockwise) until correct pressure is obtained.
    Fig 1: 1978 Fuel Shut-Off Valve Operating Pressure
    G09313119Courtesy of NISSAN NORTH AMERICA, INC.