1978 Mazda Cosmo Automatic TransFACTORY OEM SERVICE PROCEDURE

1975 Models

  1. Connect tachometer and timing light to leading spark plug wire. Disconnect water temperature switch and connect a jumper wire to both connector terminals. SeeΒ Fig 1. Start engine and set engine speed at 2000 RPM with choke knob.
  2. Observe timing marks on shaft pulley. Timing indicator should point between Yellow (leading) and Red (trailing) ignition timing marks. Engine speed should increase by several hundred RPM 104-156 seconds (96-148 seconds on pickup) after engine is started.
Fig 1: By-Passing Water Temperature Switch
G09310038Courtesy of MAZDA MOTORS CORP.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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

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