Rochester Quadrajet E4M Series

Fig. 2 Exploded view of Rochester E4MC/E4ME Quadrajet carburetor (Part 1 of 2):

Fig. 2 Exploded view of Rochester E4MC/E4ME Quadrajet carburetor (Part 2 of 2):

Fig. 3 Exploded view of Rochester E4MED Quadrajet carburetor (Part 1 of 2):

Fig. 3 Exploded view of Rochester E4MED Quadrajet carburetor (Part 2 of 2):

The E4M series (E4MC, E4ME, E4MED) carburetors, Figs. 2 and 3, are used on vehicles equipped with the Computer Command Control (C3) System. An electrically operated mixture control solenoid, mounted in the float bowl, is used to control the air and fuel metered to the idle and main metering systems of the carburetor. Fuel metering is controlled by two special stepped or tapered primary metering rods operating in removable jets. The metering rods are positioned by a plunger in the solenoid, which is controlled by an electrical signal from the electronic control module. Air metering to the idle system is controlled by an idle air bleed valve located in the air horn, which follows the movement of the mixture control solenoid plunger and thereby controls the amount of bleed air into the idle system. A throttle position sensor, mounted in the float bowl, is used to electrically signal the electronic control module as to the various changes in throttle position.
On E4MED models, a dual capacity pump valve and combined mixture control/dual capacity pump solenoid assembly is used. These assemblies provide a smoother transition from idle to part throttle operation during cold engine operation.
An idle speed solenoid or a throttle kicker assembly, depending on engine and application, is used to control curb idle speed. The throttle kicker is vacuum operated and controlled by the electronic control module. It maintains primary throttle position during deceleration, above a specified RPM. The idle speed solenoid, used primarily on air conditioned vehicles, maintains correct curb idle speed whenever the compressor clutch is engaged.
All carburetors use electrically heated choke coils. The heated coils provide choke valve closing force for cold starts, as well as correct opening timing during warm-up. Vacuum break assemblies control initial choke valve opening during starting and warm-up periods.