1976 Mazda Cosmo Automatic TransFACTORY OEM SERVICE PROCEDURE

1978 Models & 1979 RX7

  1. Connect tachometer and timing light to leading spark plug wire. Warm engine to normal operating temperature. Check to see that timing light flashes at any engine speed.
  2. Stop engine. 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.
  3. Observe timing marks on shaft pulley. Timing indicator should point between leading and trailing ignition timing marks. See Fig 1.
  4. Increase engine speed with throttle and check that timing advances and lines up with indicator when engine speed increases to more than 4600 RPM. After 130 seconds and after pulling choke knob out, portion "1" should advance quickly and portion "3" should take its place.
Fig 1: Leading Ignition Timing Test
G09310039Courtesy of MAZDA MOTORS CORP.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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