1979 Honda Prelude Automatic TransFACTORY OEM SERVICE PROCEDURE

1977-79 Models

  1. Connect tachometer to engine. Start engine and allow to reach normal operating temperature (cooling fan comes on). Check throttle opener by disconnecting hose from throttle opener diaphragm and connecting a hand-held vacuum pump.
  2. With engine running, apply at least 16 in. Hg of vacuum for more than one minute. Check that engine speed rises to RPM shown in THROTTLE OPENER SPECIFICATIONS table.
  3. If speed is too low, widen adjustment slot in throttle control linkage. See Fig 1. If speed is too high, narrow slot opening. If speed cannot be adjusted, or diaphragm will not hold vacuum, replace diaphragm and repeat test.
  4. Reconnect vacuum hose. Raise engine speed to 3500 RPM and maintain for 2-3 seconds. Quickly release throttle. Engine should return to idle in 1-4 seconds. If not, see TROUBLE SHOOTING  in this article.
    THROTTLE OPENER SPECIFICATIONS

    Application RPM
    1976 2500-3500
    1977-78
      Man. Trans. 2700
      Auto. Trans. 2200
    1979
      Civic CVCC
        Man. Trans. (1) 1700-2700
        Auto. Trans. 1500-2500
      Accord & Prelude 2000-3000
    (1) Set to 2200-3200 RPM on models with throttle control valve.
    Fig 1: Adjusting Throttle Opener Speed
    G09309910Courtesy of AMERICAN HONDA MOTOR CO., INC.
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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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