GM Cutlass RWD 1970-1987 Repair Guide

Air Injection Reactor System (AIR)


The AIR system used through 1980, injects compressed air into the exhaust system, near enough to the exhaust valves to continue the burning of the normally unburned exhaust gases. To do this it employs an air injection pump and a system of hoses, valves, tubes, etc., necessary to carry the compressed air from the pump to the exhaust manifold. Carburetors and distributors for AIR engines have specific modifications to adapt them to the air injection system; those components should not be interchanged with those intended for use on engines that do not have the system.

A diverter valve is used to prevent backfiring. The valve senses sudden increases in manifold vacuum and ceases the injection of air during fuel-rich periods. During coasting, this valve diverts the entire air flow through the pump muffler and during high engine speeds, expels it through a relief valve. Check valves in the system prevent exhaust gases from entering the pump.


The AIR system's effectiveness depends on correct engine idle speed, ignition timing, and dwell. These settings should be strictly adhered to and checked frequently. All hoses and fittings should be inspected for condition and tightness of connections. Check the drive belt for wear and tension every 12 months or 12,000 miles (19,308 Km).


Air Pump

Do not pry on the pump housing or clamp the pump in a vise: the housing is soft and may become distorted.

  1. Disconnect the negative battery cable.
  3. Disconnect the air hoses at the pump.
  5. Hold the pump pulley from turning by compressing the drive belt and loosen the pulley bolts.
  7. Loosen the pump mounting bolt and adjustment bracket bolt. Remove the drive belt.
  9. Remove the mounting bolts, and then remove the pump.

To install:
  1. Position the pump into the mounting brackets and loosely install the bolts.
  3. Install the drive belt and adjust the tension to 146 ft. lbs.(197 Nm) for a new belt and 90 ft. lbs. (122 Nm) for an old belt. Torque the mounting bolts to 25 ft. lbs. (34 Nm).
  5. Install and reconnect the pump hoses and electrical connections.

Diverter (Anti-afterburn) Valve
  1. Detach the vacuum sensing line from the valve.
  3. Tag and remove the other hose(s) from the valve.
  5. Unfasten the diverter valve from the elbow or the pump body.
  7. Installation is performed in the reverse order of removal. Always use a new gasket. Tighten the valve securing bolts to 85 inch.lbs.: