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Home >> Mazda >> 1978 >> Cosmo Standard Trans >> Repair and Diagnosis (Single Page) >> Engine Performance >> Tune-Up >> Ignition Timing Control - Rotary >> Testing >> Trailing Ignition Timing >> 1975 Models
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1975 Models

  1. Connect tachometer and timing light to trailing spark plug wire (topmost spark plug). Start engine and gradually decrease engine speed from 4500 RPM. Timing light should go out when engine speed drops to 3600-4400 RPM.
  2. With speed still decreasing, timing light should come on again at 1050-1250 RPM and remain on down to idle speed. Slowly increase engine speed. Timing light should stop flashing within 80-200 RPM (180-320 RPM on pickup) of speed at which it came on.
  3. Set engine speed to 2000 RPM (timing light out). Timing light should come on when idle switch is pushed on manual transmission equipped models (kickdown switch on RX3 and RX4 automatic transmission equipped models).
  4. On automatic transmission equipped pickup, disconnect water temperature switch and connect a jumper wire to both connector terminals. See Figure. Start engine and set engine speed at 2000 RPM with choke knob.
  5. Slowly accelerate engine. Timing light should flash at 4400-5200 RPM. Push choke knob in and gradually decrease engine speed from 3000 RPM. Timing light should stop flashing at 2300-2700 RPM.
  6. With speed still decreasing, timing light should come on again at 1050-1250 RPM and remain on down to idle speed. Slowly increase engine speed. Timing light should stop flashing within 180-320 RPM of speed at which it came on.
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