Dodge ZB 2005 Service Manual page 1100

ZB
CCV SYSTEM (Continued)
CCV HOSE CONNECTION AT THROTTLE BODY
REAR CONNECTION FOR CCV
DIAGNOSIS AND TESTING - CRANKCASE
VENTILATION SYSTEM
TESTING/CLEANING
The Crankcase Ventilation (CCV) system performs
the same function as a conventional PCV system, but
does not use a vacuum controlled valve. A vacuum
fitting containing a fixed orifice of a calibrated size is
used. It meters the amount of crankcase vapors
drawn out of the engine.
(1) Check each CCV system tube (line) for leaks,
cracks, kinks or bends. Replace as necessary
EVAPORATIVE EMISSIONS 25 - 11
CCV HOSE
(2) Disconnect each CCV tube.
(3) Blow compressed air through each tube and
check for blockage or restrictions. If cleaning is nec-
essary, spray a soapy-type all-purpose cleaner into
each component and blow out. After restriction is
cleared, rinse out component with clear water. Blow
water from component and install to vehicle. To pre-
vent damage to plastic components, never
spray carburetor-type cleaner into any of the
plastic tubes or the fixed orifice fitting. Never
attempt to clean the fixed orifice fitting with a
metal object as calibration could be affected. If
fixed fitting cannot be cleared, replace it.
EVAP/PURGE SOLENOID
OPERATION
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
width. Pulse width is the amount of time the solenoid
energizes.