HOW IT WORKS
1979 M2ME ALL (EXCEPT 3.3L V6)
A conventional vacuum enrichment system is used to provide fuel enrichment during main metering system operation. The vacuum enrichment system operates similar to past model except this carburetor model uses a mechanical enrichment system which is described in the Power System section.
1979 E2ME GENERAL APPLICATION:
- Buick 3.8L (231") V6 California Automatic
- Chevrolet Passenger 3.8L (231") V6 California Automatic
- Oldsmobile 3.8L (231") V6 California Automatic
- Pontiac 3.8L (231") V6 California Automatic
PART THROTTLE
Fuel metering is controlled by special stepped metering rods, operating in removable jets, positioned by a plunger in the mixture control solenoid. The solenoid plunger is controlled (or 'pulsed') by an electronic control module (ECM). The ECM, responding to an electricla signal from the oxygen sensor in the exhaust, energizes the solenoid to move the plunger (and rods) down to the lean position, or partially energized, up to the rich position to control fuel delivery to the main metering system. As mentioned earlier, this movement up or down of the solenoid plunger and rods in the jets occurs ten times per second.
The positioning of the mixture control solenoid in the float bowl, setting of the rich stop and idle bleed alve in the air horn, are factory adjusted to provide the most ideal air/fuel mixtures required with the catalytic convertor system and no attempt should be made to change these adjustments in the field except during major carburetor overhaul, air horn or float bowl replacement at which time service instructions must be followed carefully.
WIDE OPEN THROTTLE
A throttle actuated wide-open enrichment switch is mounted in a bracket located on the side of the float bowl. The switch, opened by a tang on the throttle lever in the wide-open position, is used to change the electrical output signal from the ECM to the carburetor solenoid plunger. In this way the plunger is "cycled" or "pulsed" by the ECM in a preprogrammed rich operating mode to obtain the richer mixtures needed for power requirements.
PULL-OVER ENRICHMENT (POE)
A supplemental source of fuel to the main metering system is used on the E2ME carburetor to provide added enrichment and improved fuel control during higher engine speeds and carburetor air flows.
A calibrated hole in each bore is located just above the choke valve and feeds fuel from a tube that extends into the fuel chamber. During high carburetor air flows, low pressure created in the air horn bores pulls fuel from the pull-over enrichment fuel feed holes supplementing fuel flow from the main metering system. The pull-over enrichment system feeds fuel at higher engine speeds to provide the additional fuel needed for good engien performance.
The air-velocity sensitive pull-over enrichment system allows the use of slightly leaner mixtures during part throttle operation and still provides enough fuel during high speed operation. This feature gives added refinement to the fuel mixtures for exhaust emission control.
