Chrysler 1997 Stratus Convertible RHD Service Manual page 1180

25 - 14 EMISSION CONTROL SYSTEMS
DESCRIPTION AND OPERATION
DUTY CYCLE EVAP PURGE SOLENOID . . . . . 14
EVAP CANISTER . . . . . . . . . . . . . . . . . . . . . . . 14
EVAPORATION CONTROL SYSTEM
POSITIVE CRANKCASE VENTILATION (PCV)
SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
PRESSURE RELIEF/ROLLOVER VALVE
PRESSURE-VACUUM FILLER CAP . . . . . . . . . 15
DESCRIPTION AND OPERATION
EVAPORATION CONTROL SYSTEM
The evaporation control system prevents the emis-
sion of fuel tank vapors into the atmosphere. When
fuel evaporates in the fuel tank, the vapors pass
through vent hoses or tubes to a charcoal filled evap-
orative canister. The canister temporarily holds the
vapors. The Powertrain Control Module (PCM) allows
intake manifold vacuum to draw vapors into the com-
bustion chambers during certain operating condi-
tions.
All engines use a duty cycle purge system. The
PCM controls vapor flow by operating the duty cycle
EVAP purge solenoid. Refer to Duty Cycle EVAP
Purge Solenoid in this section.
NOTE: The evaporative system uses specially man-
ufactured hoses. If they need replacement, only use
fuel resistant hose.
PRESSURE RELIEF/ROLLOVER VALVE
All vehicles have a combination pressure relief and
rollover valve. The dual function valve relieves fuel
tank pressure. The valve also prevents fuel flow
through the fuel tank vent valve hoses should the
vehicle rollover. All vehicles pass a 360° rollover.
The pressure relief valve opens at a certain pres-
sure. When fuel tank pressure increases above the
calibrated pressure, the valve opens to release fuel
tank vapors pressure. The charcoal filled evaporative
canister stores the vapors. For pressure relief/rollover
valve service, refer to the Fuel Tank section of Group
14.
EVAP CANISTER
All vehicles use a sealed, maintenance free, evapo-
rative (EVAP) canister. Fuel tank pressure vents into
the canister. The canister temporarily holds the fuel
EVAPORATIVE EMISSION CONTROLS
. . . . . . . . 14
. . . . . 14
INDEX
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VEHICLE EMISSION CONTROL INFORMATION
LABEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
DIAGNOSIS AND TESTING
PCV VALVE TEST
VACUUM SCHEMATIC . . . . . . . . . . . . . . . . . . . 17
REMOVAL AND INSTALLATION
LEAD DETECTION PUMP
ROLLOVER VALVES
vapors until intake manifold vacuum draws them
into the combustion chamber. The Powertrain Con-
trol Podule (PCM) purges the canister through the
duty cycle EVAP purge solenoid. The PCM purges the
canister at predetermined intervals and engine con-
ditions.
The canister mounts to a bracket behind the front
fascia on the passengers side of the vehicle (Fig. 1).
The vacuum and vapor tube connect to the top of the
canister.
DUTY CYCLE EVAP PURGE SOLENOID
The duty cycle EVAP purge solenoid regulates the
rate of vapor flow from the EVAP canister to the
throttle body. The Powertrain Control Module (PCM)
operates the solenoid.
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged.
When purging the PCM energizes and de-energizes
the solenoid approximately 5 or 10 times per second,
depending upon operating conditions. The PCM var-
ies the vapor flow rate by changing solenoid pulse
EVAPORATIVE CANISTER
. . . . . . . . . . . . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . 21
. . . . . . . . . . . . . . . . . . . . 22
Fig. 1 EVAP Canister
JX
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