1987 Subaru XT GL, AutomaticFACTORY OEM SERVICE PROCEDURE

Air Injection System: Operation

Negative pressure from exhaust pulsation reaches suction valve through suction pipe. This causes reeds in suction valve to draw open. Secondary (fresh) air from air cleaner is drawn through silencer(s) and into exhaust passages. See Fig 1 or Fig 2 .

When positive pressure is present in exhaust, reeds are closed to prevent reverse flow of exhaust gas.

Fig 1: Air Injection (Justy)
G67252Courtesy of SUBARU OF AMERICA, INC.
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When to See a Mechanic

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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