Jeep J-10 Series 1982 Technical & Service Manual page 343

VAPOR VENT
TUBE {TO
CANISTER)
SECONDARY
AIR VALVE
SECONDARY
AIR VALVE
LEVER
CHOKE
VALVE
VACUUM
BREAK
OLE SPEED
SOLENOID
SLOW IDLE FAST IDLE
SPEED ADJUSTMENT
ADJUSTMENT SCREW
SCREW 90724
Fig. U-53 Model E2SE Carburetor
NOTE: .4// reference to CJ vehicles also pertains to
Sera m bier veh icles.
When used with the C4 system, the Model E2SE car
buretor includes special design features for optimum
air/fuel mixture control during all ranges of engine
operation. An electrically operated mixture control sole
noid, located in the air horn, is used to control air and
fuel metered to the idle and main metering systems of
the carburetor. A plunger in the end of the solenoid is
submerged in fuel in the fuel chamber of the float bowl.
The solenoid is turned on and off (or "pulsed") by the
Electronic Control Module (ECM). The ECM, responding
to the amplitude of the voltage at the oxygen sensor in
the exhaust manifold and other engine operating condi
tions, energizes the solenoid to move the plunger down
to the lean position or, de-energizes it to the rich position
to control fuel delivery to the idle and main metering
circuits. The ECM energizes the solenoid by providing a
ground to complete the path for current flow. The sole
noid has 12 volts (battery voltage) applied to it at all
times while the ignition switch is on. When the plunger
is in the down (lean) position, fuel metering is controlled
by a factory adjusted lean mixture screw located in the
float bowl. When the plunger is in the up (rich position),
additional fuel is metered to the main fuel well through
the factory adjusted rich mixture screw located at the
end of the fuel supply channel in the float bowl.
In addition, air metered to the idle circuit is controlled
by the up and down movement of the mixture control
solenoid plunger. The plunger either increases or de
creases air supplied to the idle circuit, which is further
metered by a factory adjusted idle air bleed screw.
The movement (or "cycling") of the solenoid plunger,
up or down, occurs ten times per second. The ratio (duty
FUEL SYSTEMS 1J-31
cycle) of "on" to "off" time, or dwell period, is varied by
the ECM according to the engine operating conditions.
This varies the fuel and air mixture to achieve, as near
as possible, optimum air/fuel mixture ratios. The ex
haust gas mixture oxygen content (lean or rich), and
other engine operating conditions, are constantly mon
itored by the C4 system microprocessor (ECM) and the
air/fuel mixture is adjusted accordingly for improved
exhaust emission control and good engine performance.
Identification
The carburetor model identification is stamped verti
cally into the float bowl at a flat area adjacent to the
vacuum tube (fig. 1J-59). When replacing the fuel bowl,
follow the manufacturer's instructions contained in the
service repair package and ensure that the identification
number is transferred to the new float bowl. Refer to the
bowl part number when servicing the carburetor.
Fig. 1J-59 Model E2SE Carburetor-Identification
CARBURETOR CIRCUITS
The model E2SE carburetor has six basic circuits.
They are:
• Float
•Idle
• Main Metering
• Power Enrichment
•Pump
• Choke
Float Circuit
The float chamber is located next to the primary and
secondary bores (fig. 1J-60). This feature assures ade
quate fuel supply to both carburetor venturi bores dur
ing all normal engine operations.