Chrysler Sebring, Stratus sedan, Sebring Convertible. Manual — part 547
(1) Position fuel rail assembly so that the fuel
injectors are easily accessible (Fig. 13).
(2) Remove injector clip and pull injector out of
fuel rail.
(3) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. Replace the injector
clip if it is damaged.
(4) Repeat for remaining injectors.
REMOVAL - 2.7L
(1) Release fuel system pressure. Refer to Fuel
System Pressure Release Procedure in this section.
(2) Disconnect negative cable to battery.
(3) Remove intake manifold plenum. Refer to the
Engine section for information.
(4) Remove intake manifold plenum mounting
bolts. Lift Plenum up off of engine. Cover intake
manifold to prevent foreign material from entering
engine.
(5) Disconnect fuel supply tube quick connect fit-
tings at the rear of intake manifold. Refer to Quick
Connect Fittings in the Fuel Delivery Section.
(6) If the injector connectors are not tagged with
their cylinder number, tag them to identify the cor-
rect cylinder
(7) Remove electrical connectors from the fuel
injectors.
(8) Remove fuel rail mounting bolts.
(9) Lift fuel rail straight up off of the cylinder
head.
(10) Remove retaining clips from fuel injectors at
fuel rail.
(11) Remove fuel injectors.
(12) Repeat for remaining injectors.
(13) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. Replace the injector
clip if it is damaged.
INSTALLATION
INSTALLATION - 4 CYLINDER
(1) Before installing an injector the rubber O-ring
must be lubricated with a drop of clean engine oil to
aid in installation.
(2) Install injector clip by sliding open end into the
top slot of the injector. The edge of the receiver cup
will slide into the side slots of clip.
(3) Install injector top end into fuel rail receiver
cap. Be careful not to damage O-ring during installa-
tion (Fig. 14).
(4) Repeat steps for remaining injectors.
(5) Install the fuel rail, refer to the Fuel Rail
Installation in this section.
INSTALLATION - 2.7L
(1) Lightly lubricate the fuel injector O-rings with
a couple drops of clean engine oil.
(2) Install fuel injectors.
(3) Install retaining clips on fuel injectors.
(4) Push injectors into fuel injector rail until clips
are in the correct position.
(5) Position fuel rail over cylinder head, and push
rail into place. Tighten fuel rail mounting bolts to 11
N·m (100 in. lbs.) torque.
Fig. 13 FUEL INJECTOR AND RAIL - TYPICAL
1 - FUEL RAIL ASSEMBLY
2 - FUEL INJECTOR
3 - FUEL RAIL RECEIVER
Fig. 14 SERVICING FUEL INJECTOR TYPICAL
1 - FUEL INJECTOR
2 - LOCKING SLOT
3 - FUEL RAIL RECEIVER CUP
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FUEL INJECTION
14 - 25
FUEL INJECTOR (Continued)
(6) Connect fuel supply tube quick connect fittings
at the rear of intake manifold. Refer to Quick Con-
nect Fittings in the Fuel Delivery Section.
(7) Connect electrical connectors to fuel injectors.
(8) Install intake manifold plenum. Refer to the
Engine section for information.
(9) Connect negative cable to battery.
FUEL PUMP RELAY
DESCRIPTION
The fuel pump relay is located in the PDC. The
inside top of the PDC cover has a label showing relay
and fuse location.
OPERATION
The fuel pump relay supplies battery voltage to the
fuel pump. A buss bar in the Power Distribution Cen-
ter (PDC) supplies voltage to the solenoid side and
contact side of the relay. The fuel pump relay power
circuit contains a fuse between the buss bar in the
PDC and the relay. The fuse is located in the PDC.
Refer to the Wiring Diagrams for circuit information.
The PCM controls the fuel pump relay by switch-
ing the ground path for the solenoid side of the relay
on and off. The PCM turns the ground path off when
the ignition switch is in the Off position. When the
ignition switch is in the On position, the PCM ener-
gizes the fuel pump. If the crankshaft position sensor
does not detect engine rotation, the PCM de-ener-
gizes the relay after approximately one second.
IDLE AIR CONTROL MOTOR
DESCRIPTION
The idle air control valve (IAC) attaches to the
throttle body (Fig. 15) or (Fig. 16). It is a linear sole-
noid valve on the NGC vehicles.
OPERATION
The PCM adjusts engine idle speed through the
idle air control valve to compensate for engine load,
coolant temperature or barometric pressure changes.
The throttle body has an air bypass passage that
provides air for the engine during closed throttle idle.
The idle air control valve regulates air flow through
the bypass passage.
The PCM controls engine idle speed by adjusting
the position of the idle air control valve. The adjust-
ments are based on inputs the PCM receives. The
inputs are from the throttle position sensor, crank-
shaft position sensor, coolant temperature sensor,
MAP sensor, vehicle speed sensor and various switch
operations (brake, park/neutral, air conditioning).
When engine rpm is above idle speed, the IAC is
used for the following functions:
• Off-idle dashpot
• Deceleration air flow control
• A/C compressor load control (also opens the pas-
sage slightly before the compressor is engaged so
that the engine rpm does not dip down when the
compressor engages)
Target Idle
Target idle is determined by the following inputs:
• Gear position
• ECT Sensor
Fig. 15 IAC VALVE 4 CYLINDER
Fig. 16 IDLE AIR CONTROL VALVE 2.7L
1 - THROTTLE POSITION SENSOR
2 - IDLE AIR CONTROL VALVE
14 - 26
FUEL INJECTION
JR
FUEL INJECTOR (Continued)
• Battery voltage
• Ambient/Battery Temperature Sensor
• VSS
• TPS
• MAP Sensor
REMOVAL
REMOVAL - 4 CYLINDER
When servicing throttle body components, always
reassemble components with new O-rings and seals
where applicable. Never use lubricants on O-rings or
seals, damage may result.
(1) Disconnect negative cable from battery.
(2) Remove electrical connector from idle air con-
trol valve.
(3) Remove idle air control valve mounting screws
(Fig. 15).
(4) Remove motor from throttle body. Ensure the
O-ring is removed with the valve.
REMOVAL - 2.7L
(1) Disconnect the negative battery cable.
(2) Disconnect the IAC electrical connector (Fig.
17).
(3) Remove the IAC mounting screw.
(4) Remove the IAC.
INSTALLATION
INSTALLATION - 4 CYLINDER
When servicing throttle body components, always
reassemble components with new O-rings (Fig. 18)
and seals where applicable.
(1) The new idle air control valve has a new O-ring
installed on it.
(2) Carefully place idle air control valve into throt-
tle body (Fig. 15).
(3) Install mounting screw. Tighten screw to 4.5
N·m (40 in. lbs.) torque.
(4) Connect electrical connector to idle air control
valve
(5) Connect negative cable to battery.
INSTALLATION - 2.7L
(1) Install the IAC to the throttle body (Fig. 17).
(2) Tighten mounting screws to 5.1 N·m (45 in.
lbs.) torque.
(3) Attach electrical connector to the IAC.
(4) Connect the negative battery cable.
Fig. 17 Idle Air Control Valve
1 - THROTTLE POSITION SENSOR
2 - IDLE AIR CONTROL VALVE
Fig. 18 O-RINGS
1 - O-rings
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FUEL INJECTION
14 - 27
IDLE AIR CONTROL MOTOR (Continued)
INLET AIR TEMPERATURE
SENSOR
DESCRIPTION
The IAT Sensor is a Negative Temperature Coeffi-
cient (NTC) Sensor that provides information to the
PCM regarding the temperature of the air entering
the intake manifold (Fig. 19).
MAP SENSOR
DESCRIPTION
The MAP sensor mounts to the driver side of the
intake manifold plenum (Fig. 20) or (Fig. 21).
OPERATION
The MAP serves as a PCM input, using a silicon
based sensing unit, to provide data on the manifold
vacuum that draws the air/fuel mixture into the com-
bustion chamber. The PCM requires this information
to determine injector pulse width and spark advance.
When MAP equals Barometric pressure, the pulse
width will be at maximum.
Also like the cam and crank sensors, a 5 volt ref-
erence is supplied from the PCM and returns a volt-
age
signal
to
the
PCM
that
reflects
manifold
pressure. The zero pressure reading is 0.5V and full
scale is 4.5V. For a pressure swing of 0 — 15 psi the
voltage changes 4.0V. The sensor is supplied a regu-
lated 4.8 to 5.1 volts to operate the sensor. Like the
cam and crank sensors ground is provided through
the sensor return circuit.
The MAP sensor input is the number one contrib-
utor to pulse width. The most important function of
the MAP sensor is to determine barometric pressure.
The PCM needs to know if the vehicle is at sea level
or is it in Denver at 5000 feet above sea level,
because the air density changes with altitude. It will
also help to correct for varying weather conditions. If
a hurricane was coming through the pressure would
be very, very low or there could be a real fair
weather, high pressure area. This is important
because as air pressure changes the barometric pres-
sure changes. Barometric pressure and altitude have
a direct inverse correlation, as altitude goes up baro-
metric pressure goes down. The first thing that hap-
pens as the ignition key is rolled on, before reaching
the crank position, the PCM powers up, and looks at
the MAP voltage, and based upon the voltage it sees,
it knows the current barometric pressure relative to
altitude. Once the engine starts, the PCM looks at
the voltage again, continuously every 12 milliseconds,
and compares the current voltage to what it was at
key on. The difference between current and what it
was at key on is manifold vacuum.
During key On (engine not running) the sensor
reads (updates) barometric pressure. A normal range
can be obtained by monitoring known good sensor in
your work area.
As the altitude increases the air becomes thinner
(less oxygen). If a vehicle is started and driven to a
very different altitude than where it was at key On
the barometric pressure needs to be updated. Any
time the PCM sees Wide Open throttle, based upon
TPS angle and RPM it will update barometric pres-
sure in the MAP memory cell. With periodic updates,
the PCM can make its calculations more effectively.
Fig. 19 TPS AND INLET AIR TEMP. SENSOR 2.7L
1 - Throttle Position Sensor
2 - Inlet Air Temperature Sensor
Fig. 20 MAP Sensor 2.7L
1 - MAP SENSOR
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FUEL INJECTION
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