1987 Honda Prelude Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Pulse Air System: Operation

When vehicle exceeds set speed of speed sensor and manifold vacuum is above set vacuum of control switch, control switch solenoid valve and control switch are open. The control unit energizes the air suction control solenoid valve, applying manifold vacuum to air suction cut-off diaphragm valve. This will in turn open secondary air passage.

When vacuum, induced by pulsation in exhaust manifold, makes air suction reed valve open, fresh air enters exhaust manifold. The control switch bellows adjust their operation in response to atmospheric pressure. Air chambers act as silencers to reduce exhaust noise.

Fig 1: Pulse Air System
G36682Courtesy 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:

  • 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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