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Oxygen Sensor Test

  1. Set parking brake and connect tachometer. Run engine at 1500 RPM and connect voltmeter to carburetor-to-computer output wire (Green). DO NOT  ground carburetor switch. Hold choke blade closed. During the next 10 seconds, the voltage should decrease to 3 volts or less and maintain that level. If engine does not respond, proceed to step 2).
  2. Disconnect PCV system. During the next 10 seconds, the voltage should increase to 9 volts or greater and maintain that level until vacuum hose is reconnected. If sensor fails both tests, replace it. Reconnect all hoses and wires.
NOTE: This test should not be performed for more than 90 seconds.