Carburetor - ROCHESTER E4MC/E4ME 4-Bbl: Description

The 2-stage, downdraft design, E4MC and E4ME carburetors are composed of 3 main components, air horn, float bowl and throttle body. All E4MC and most E4ME models have 2 vacuum break diaphragm assemblies, primary and secondary. Some E4ME models have only primary vacuum break assembly.

Both the E4MC and E4ME models are used in conjunction with the computerized engine control system. Carburetors are equipped with an electrically-actuated Mixture Control (MC) solenoid mounted in the float bowl. Fuel delivery is controlled by the MC as indicated 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. Some E4ME models contain an Idle Stop Solenoid (ISS). This solenoid is used to increase idle when A/C is operated (if equipped) or extends the plunger during deceleration to improve emissions.

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.