Carburetor - ROCHESTER E4MC 4-Bbl: Description

The 2-stage, downdraft design, E4MC carburetor is composed of 3 main components, air horn, float bowl and throttle body. E4MC models have 2 vacuum break diaphragm assemblies, primary and secondary.

The E4MC carburetor is used in conjunction with the Computer Command Control (CCC) computerized engine control system. Carburetor is equipped with an electrically-actuated Mixture Control (MC) solenoid mounted in the float bowl. Fuel delivery is controlled by the MC solenoid in response to signals generated by the computer. Fuel metering is controlled by stepped metering rods and jets.

A Throttle Position Sensor (TPS) is contained in the carburetor and varies resistance reading to the computer, indicating throttle position changes. An Idle Load Compensator (ILC) is used on E4MC models. The ILC increases idle speed during increased engine load conditions such as A/C operation or increased power steering loads. ILC will also increase throttle opening during periods of extended deceleration (such as coasting downhill).