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Home >> Mazda >> 1978 >> Cosmo Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Exhaust Emissions System - Deceleration Control System - Rotary Engines >> Testing >> Idle Switch >> 1974 Models
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1974 Models

  1. Disconnect idle switch. Check continuity between ignition switch terminal "A" and control unit terminal "C". Continuity should exist.
  2. Check continuity between ignition switch terminal "A" and costing valve solenoid terminal "B" when external force is applied to switch knob (primary throttle valve in idle position). No continuity should exist.
  3. If there is no continuity between ignition switch and control unit and continuity between ignition switch and coasting valve solenoid, idle switch is operating properly.
  4. If necessary, adjust switch with engine warm. Set engine speed to idle speed by turning by-pass adjusting screw. Using accelerator pedal, increase and decrease engine speed making sure switch comes on and off. Switch cycles from on to off at 1000-1100 RPM (1100-1250 RPM with auto, trans.).
  5. If switch does not change at specified RPM, adjust by turning adjusting screw of idle switch lever. Turning screw counterclockwise lowers RPM. Turning screw clockwise increases RPM.
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