Chrysler Concorde 1993 Service Manual page 522

When energized, the MTV solenoid allows vacuum
to reach and close the manifold tuning valve. When
not energized, the solenoid closes and vacuum bleeds
off from the manifold tuning valve vacuum motor.
The manifold tuning valve opens the crossover when
the solenoid de-energizes.
The MTV solenoid shares a bracket with the duty
cycle EVAP purge solenoid. The solenoids and
bracket attach to the right inner fender well next to
the dash panel (Fig. 23).
Fig. 23 EVAP Purge and MTV Solenoids
EGR SOLENOID—PCM OUTPUT
The electronic EGR transducer (EET) contains an
electrically operated solenoid and a back-pressure
transducer (Fig. 24). The powertrain control module
(PCM) operates the solenoid. The PCM determines
when to energize the solenoid. Exhaust system back-
pressure controls the transducer.
Fig. 24 EGR Solenoid
When the PCM energizes the solenoid, vacuum
does not reach the transducer. Vacuum flows to the
transducer when the PCM de-energizes the solenoid.
When exhaust system back-pressure becomes high
enough, it fully closes a bleed valve in the trans-
ducer. When the PCM de-energizes the solenoid and
back-pressure closes the transducer bleed valve, vac-
uum flows through the transducer to operate the
EGR valve.
De-energizing the solenoid, but not fully closing
the transducer bleed hole (because of low back-pres-
sure), varies the strength of vacuum applied to the
EGR valve. Varying the strength of the vacuum
changes the amount of EGR supplied to the engine.
This provides the correct amount of exhaust gas re-
circulation for different operating conditions.
DUTY CYCLE EVAP PURGE SOLENOID—PCM
OUTPUT
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 and the hot start
time delay, the PCM does not energize the solenoid.
When de-energized, no vapors are purged. The PCM
de-energizes the solenoid during open loop operation.
The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM ener-
gizes and de-energizes the solenoid approximately 5
to 10 times per second, depending upon operating
conditions. The PCM varies the vapor flow rate by
changing solenoid pulse width. Pulse width is the
amount of time the solenoid energizes. The PCM ad-
just solenoid pulse width based on fuel requirements.
The EVAP purge solenoid and bracket attach to
the right inner fender well next to the dash panel
(Fig. 23). The top of the solenoid has the word TOP
on it. The solenoid will not operate unless it is in-
stalled correctly. If the vehicle has a 3.5L engine, the
EVAP purge solenoid shares a bracket with the MTV
solenoid.
FUEL INJECTORS—PCM OUTPUT
The 3.5L engine uses bottom feed injectors. Fuel
from the rail enters the side of the injectors (Fig. 25).
The 3.3L engines uses top feed injectors (Fig. 26).
The automatic shutdown (ASD) relay supplies bat-
tery voltage to the injectors. The PCM controls the
ground path for each injector in sequence. By switch-
ing the ground paths on and off, the PCM fine-tunes
injector pulse width. Injector pulse width refers to
the amount of time an injector operates.
The PCM determines injector synchronization from
the camshaft position sensor and crankshaft position
sensor inputs. The PCM grounds the ASD and fuel
pump relays after receiving the camshaft position
sensor and crankshaft position sensor inputs.
The PCM energizes the injectors in a sequential or-
der during all engine operating conditions except
FUEL SYSTEMS 14 - 29