Mixture Control Unit

The air-flow sensor contains a plate mounted on a hinged lever which moves in a cone-shaped venturi. This illustration is typical of all models. Details among models may vary. All engine air is drawn past this sensor. The plate moves as air is drawn into the engine, moving the hinged lever up or down.

Movement of the sensor plate raises or lowers a fuel control plunger in the fuel distributor, which meters the amount of fuel injected into each cylinder. The movement of the plate is controlled by air flow, cone shape of venturi, a balance weight, and fuel pressure.

NOTE: Air flows UP through the sensor on most inline engines, and DOWN through the sensor on V6, V8 and turbocharged engines. The direction of air flow does not affect system operation. It is changed for convenience of routing air flow.

Fuel distribution can be equal only if the pressure to each injector is equal. Pressure regulating valves in the fuel distributor equalize system pressure. These valves are adjusted during assembly of fuel distributor and cannot be adjusted in service.