Colt L4-1597cc 1.6L SOHC Turbo (1985)
Secondary Air Supply: Description and Operation
With Pulse Air Feeder
Fig. 4 Secondary air supply system. Models w/pulse air feeder (Typical)
On this system, Fig. 4, a Pulse Air Feeder (PAF) is used to supply secondary air to the exhaust system between the front and rear catalytic converters.
This secondary air combines with exhaust gasses to promote further oxidation in the rear catalytic converter.
A main and sub-reed valve is incorporated in the Pulse Air Feeder. The main reed valve is actuated by a diaphragm which senses pressure pulsations
caused by piston movement in the No. 3 cylinder. The sub-reed valve is actuated by exhaust gas vacuum caused by pulsations in the exhaust system
between the front and rear catalytic converters.
