(8) Remove oil pressure relief valve. (Refer to 9 -
ENGINE/LUBRICATION/OIL PRESSURE RELIEF
VALVE - REMOVAL)
(9) Inspect oil pressure relief valve and bore.
Inspect for scoring, pitting and free valve operation
in bore (Fig. 113). Small marks may be removed with
400-grit wet or dry sandpaper.
(10) The relief valve spring has a free length of
approximately 49.5 mm (1.95 inches) it should test
between 19.5 and 20.5 pounds when compressed to
34 mm (1-11/32 inches). Replace spring that fails to
meet specifications.
(11) If oil pressure is low and pump is within spec-
ifications, inspect for worn engine bearings or other
reasons for oil pressure loss.
ASSEMBLY
(1) Assemble pump, using new parts as required.
Install the inner rotor with chamfer facing the
cast iron oil pump cover.
(2) Prime oil pump before installation by filling
rotor cavity with engine oil.
(3) Install cover and tighten screws to 12 N´m (105
in. lbs.).
(4) If removed, install the oil pressure relief valve.
(Refer to 9 - ENGINE/LUBRICATION/OIL PRES-
SURE RELIEF VALVE - INSTALLATION)
INSTALLATION
(1) Install oil pump. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PUMP - ASSEMBLY)
Fig. 109 Measuring Inner Rotor Thickness
Fig. 110 Measuring Outer Rotor Clearance in
Housing
1 - FEELER GAUGE
2 - OUTER ROTOR
Fig. 111 Measuring Clearance Between Rotors
1 - FEELER GAUGE
2 - INNER ROTOR
3 - OUTER ROTOR
Fig. 112 Measuring Clearance Over Rotors
1 - FEELER GAUGE
2 - STRAIGHT EDGE
9 - 146 ENGINE 3.3/3.8LRS
OIL PUMP (Continued)
(2) Install timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION) and oil pan (Refer to 9
- ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
INTAKE MANIFOLD
DESCRIPTION
The intake system is made up of an upper and
lower intake manifold. The upper intake manifold is
made of a composite for both the 3.3L engine and for
the 3.8L engine (Fig. 118). The lower intake manifold
is common between the two engines (Fig. 122). It also
provides coolant crossover between cylinder heads
and houses the coolant thermostat (Fig. 122).
The intake manifold utilizes a compact design with
very low restriction and outstanding flow balance.
This design allows the engine to perform with a wide
torque curve while increasing higher rpm horse-
power.
If, for some reason, the molded-in vacuum ports
break, the composite manifold can be salvaged. The
vacuum ports are designed to break at the shoulder,
if overloaded. Additional material in the shoulder
area provides sufficient stock to repair. For more
information and procedure, (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - STANDARD
PROCEDURE). Also, if the special screws that attach
the MAP sensor, power steering reservoir, throttle
cable bracket, and the EGR tube become stripped, an
oversized screw is available to repair the stripped-out
condition. For more information and procedure,
(Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANI-
FOLD - STANDARD PROCEDURE)
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water (Spray Bottle) at
the suspected leak area.
(3) If engine RPM'S change, the area of the sus-
pected leak has been found.
(4) Repair as required.
INTAKE MANIFOLD - UPPER
STANDARD PROCEDURE
STANDARD PROCEDURE - MANIFOLD
STRIPPED THREAD REPAIR
The composite upper intake manifold thread
bosses, if stripped out, can be repaired by utilizing a
repair screw available through Mopartparts. Repair
screws are available for the following manifold
attached components:
²MAP sensor
²Power steering reservoir
²EGR tube
²Throttle cable bracket
The repair screws require a unique tightening
torque specification from the original screw. Refer to
the following chart for specification.
DESCRIPTION TORQUE*
STRIP-OUT REPAIR SCREWS ONLY
MAP Sensor Repair
Screw4 N´m (35 in. lbs.)
Power Steering Reservoir
Repair Screw9 N´m (80 in. lbs.)
EGR Tube Attaching
Repair Screw9 N´m (80 in. lbs.)
Throttle Cable Bracket
Repair Screw9 N´m (80 in. lbs.)
*Install Slowly Using Hand Tools Only
Fig. 113 Oil Pressure Relief Valve
1 - RELIEF VALVE
2 - SPRING
3 - RETAINER CAP
RSENGINE 3.3/3.8L9 - 147
OIL PUMP (Continued)
(5) Connect the MAP sensor electrical connector.
(6) Connect the brake booster and LDP vacuum
hose to intake manifold (Fig. 117).CAUTION: The special screws used for attaching
the EGR tube and power steering reservoir to the
manifold must be installed slowly using hand tools
only. This requirement is to prevent the melting of
material that causes stripped threads. If threads
become stripped, an oversize repair screw is avail-
able. For more information and procedure (Refer to
9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD - STAN-
DARD PROCEDURE - MANIFOLD STRIPPED
THREAD REPAIR).
(7) Install the power steering reservoir (Fig. 116).
Tighten screws to manifold to 5.6 N´m (50 in. lbs.).
(8) Connect throttle and speed control cables to
throttle body (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/THROTTLE CONTROL CABLE -
INSTALLATION)
(9) Attach make up air hose clip into the hole in
the throttle cable bracket.
(10) Connect the wiring connectors to the throttle
position sensor (TPS) and Automatic Idle Speed (AIS)
motor.
(11) Install air cleaner and air inlet hose assembly.
(12) Connect the inlet air temperature (IAT) sen-
sor electrical connector.
(13) Connect battery negative cable.
INTAKE MANIFOLD - LOWER
REMOVAL - LOWER INTAKE MANIFOLD
(1) Perform fuel system pressure release procedure
(before attempting any repairs).(Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY - STANDARD
PROCEDURE)
(2) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(3) Remove the upper intake manifold. (Refer to 9
- ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL)
(4) Remove the fuel line. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/FUEL LINES - STANDARD
PROCEDURE) (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE)
(5) Remove ignition coil and bracket (Fig. 120).
(6) Disconnect heater supply hose and engine cool-
ant temperature sensor (Fig. 121).
(7) Disconnect the fuel injector wire harness.
(8) Remove the fuel injectors and rail assembly
(Fig. 120).
(9) Remove radiator upper hose.
(10) Remove the intake manifold bolts.
(11) Remove lower intake manifold (Fig. 122).
Fig. 118 INTAKE MANIFOLD - UPPER
1 - BOLT
2 - MAP SENSOR
3 - SCREW
4 - MANIFOLD - UPPER
5 - WIRE HARNESS
6 - GASKET (3 PER CYL. BANK)
Fig. 119 UPPER MANIFOLD TIGHTENING
SEQUENCE
9 - 150 ENGINE 3.3/3.8LRS
INTAKE MANIFOLD - UPPER (Continued)
REMOVAL
The front cradle crossmember must be installed in
the design location to achieve proper front end sus-
pension alignment. If the cradle crossmember is
removed without applying reference marks on the
frame rails, align the cradle crossmember according
to the dimensions provided in this group.
NOTE: If the caged nuts in the frame rails become
damaged and cannot be reused, a replacement nut
can be obtained through MoparT(Fig. 14).
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove steering column lower cover from
instrument panel (Refer to 23 - BODY/INSTRU-
MENT PANEL/STEERING COLUMN OPENING
COVER - REMOVAL).
(3) Remove steering column cover backing plate
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN COVER BACKING PLATE -
REMOVAL).
(4) Position steering so front wheels are straight
ahead.
CAUTION: Do not rotate steering wheel after disen-
gaging lower coupling from steering gear, damage
to air bag clock spring can result.
(5) Remove clinch bolt attaching steering column
coupling to steering gear shaft (Fig. 15).
(6) Remove steering column coupling from tele-
scoping steering gear shaft.(7) Hoist vehicle and support on safety stands.
(8) Position a drain pan under power steering
pump and oil return hose coupling.
(9) Using a hose pinch-off pliers (C-4390), pinch
power steering oil return hose off between the cross-
member coupling and the pump.
(10) Loosen hose clamp at the cradle crossmember
coupling.
(11) Disconnect return hose from metal tube.
(12) While holding pressure relief valve nut on
back of power steering pump, Remove flare nut
attaching high pressure hose to back of pump.
(13) Remove high pressure hose from pump.
(14) Allow power steering fluid to drain into pan.
(15) Remove bolts attaching anti-lock brake sensor
leads to cradle crossmember.
(16) Position anti-lock brake leads out of the way.
(17) Disconnect stabilizer bar links from ends of
stabilizer bar.
(18) Disconnect lower ball joints from lower steer-
ing knuckles (Refer to 2 - SUSPENSION/FRONT/
LOWER BALL JOINT - REMOVAL).
(19) Remove the rear engine mount heat shield
(Fig. 16).
(20) Remove through bolt attaching rear engine
mount to cradle crossmember (Fig. 17).
(21) Using paint or grease pencil, mark outline of
cradle crossmember on frame rails to aid installation.
(22) Support cradle crossmember on suitable lift-
ing device (Fig. 19).
(23) Remove bolts attaching crossmember to front
frame rails (Fig. 18).
(24) Remove cradle crossmember from vehicle (Fig.
19).
Fig. 14 FRONT CRADLE CROSSMEMBER CAGED
NUT
1 - BRACKET
2 - CAGED NUT
Fig. 15 STEERING COUPLING
1 - STEERING SHAFT BOOT
2 - STEERING SHAFT
3 - CROSSMEMBER
4 - STEERING GEAR
5 - MOUNT
6 - TRANSAXLE
RSFRAME & BUMPERS13-15
FRONT CRADLE CROSSMEMBER (Continued)
(1) Lightly lubricate the O-rings with clean engine
oil and place them into opening in pump module (Fig.
9).
(2) Push regulator into opening in pump module.
(3) Retaining tabs snap into housing.
FUEL PUMP
DESCRIPTION
The electric fuel pump is located in and is part of
the fuel pump module. It is a positive displacement,
gerotor type, immersible pump with a permanent
magnet electric motor. The fuel pump module is sus-
pended in fuel in the fuel tank.
OPERATION
The pump draws fuel through a strainer and
pushes it through the motor to the outlet. The pump
contains a check valve. The valve, in the pump out-
let, maintains pump pressure during engine off con-
ditions, for a short while. It is normal for fuel
pressure to drop to zero after cooldown. The fuel
pump relay provides voltage to the fuel pump. The
fuel pump has a maximum deadheaded pressure out-
put of approximately 880 kPa (130 psi). The regula-
tor adjusts fuel system pressure to approximately
400 kpa 34 kpa (58 psi 5 psi).
FUEL PUMP MODULE
DESCRIPTION
The fuel pump module is installed in the top of the
fuel tank (Fig. 10), (Fig. 11), and (Fig. 12).The fuel pump module contains the following:
²Electric fuel pump
²Fuel pump reservoir
²Inlet strainer
²Fuel pressure regulator
²Fuel gauge sending unit
Fig. 9 Fuel Pressure Regulator O-rings
1 - UPPER O-RING
2 - LOWER 0-RING
Fig. 10 LEVEL SENSOR - FOLD-IN-FLOOR
2 - FUEL PUMP MODULE
3 - PRESSURE REGULATOR
4 - FUEL LEVEL SENDER
Fig. 11 REGULATOR AND WIRING - FOLD-IN-FLOOR
2 - FUEL RESERVOIR
3 - PRESSURE REGULATOR
6 - GROUND STRAPS
14 - 8 FUEL DELIVERYRS
FUEL PRESSURE REGULATOR (Continued)
INSTALLATION - 3.3/3.8L
(1) Ensure injector holes are clean. Replace
O-rings if damaged.
(2) Lubricate injector O-rings with a drop of clean
engine oil to ease installation.
(3) Put the tip of each injector into their ports.
Push the assembly into place until the injectors are
seated in the ports.
(4) Install the fuel rail mounting bolts. Tighten
bolts to 22 N´m (200 in. lbs.) torque.
(5) Remove covering on lower intake manifold and
clean surface.
(6) Install the Upper Intake Manifold, refer to
Engine/Manifolds/Upper Intake for more information.
(7) Install fuel hose quick connector fitting to chas-
sis tubes.Refer to Fuel Hoses, Clamps and
Quick Connect Fittings in this Section.Push the
fitting onto the chassis tube until it clicks into place.
Pull on the fitting to ensure complete insertion.
(8) Connect negative cable to battery.
(9) Use the DRBIIItscan tool to pressurize the
fuel system. Check for leaks.
FUEL TANK
DESCRIPTION
The fuel tank is constructed of a plastic material.
Its main functions are for fuel storage and for place-
ment of the fuel pump module. The tank is made
from High density Polyethylene (HDPE) material.If
equipped with ORVR (Onboard Refueling Vapor
Recovery) it has been added to the fuel tank to con-
trol refueling vapor emissions.
OPERATION
All models pass a full 360 degree rollover test
without fuel leakage. To accomplish this, fuel and
vapor flow controls are required for all fuel tank con-
nections.
All models are equipped with either one or two
check valves mounted into the top of the fuel tank (or
pump module).
An evaporation control system is connected to the
check valve(s)/control valve(Refer to 25 - EMIS-
SIONS CONTROL/EVAPORATIVE EMISSIONS/
ORVR - OPERATION) to reduce emissions of fuel
vapors into the atmosphere, when the tank is vented
due to vapor expansion in the tank. When fuel evap-
orates from the fuel tank, vapors pass through vent
hoses or tubes to a charcoal canister where they are
temporarily held. When the engine is running, the
vapors are drawn into the intake manifold. In addi-
tion, fuel vapors produced during vehicle refueling
are allowed to pass through the vent hoses/tubes to
the charcoal canister(s) for temporary storage (priorto being drawn into the intake manifold). All models
are equipped with a self-diagnosing system using a
Leak Detection Pump (LDP) or Natural Vacuum
Leak Detection (NVLD). Refer to the Emission Con-
trol System for additional information.
INLET CHECK VALVE
All vehicles have an inlet check valve on the inside
of the fuel tank at the filler inlet
The valve prevents fuel from splashing back on
customer during vehicle refueling. The valve is a
non-serviceable item.
REMOVAL
REMOVAL
(1) Remove fuel filler cap and perform Fuel Sys-
tem Pressure Release procedure (Fig. 18).
(2) Disconnect negative cable from battery.
(3) Insert fuel siphon hose into fuel filler neck and
push it into the tank.
(4) Drain fuel tank dry into holding tank or a
properly labeledGASOLINEsafety container.
(5) Raise vehicle on hoist and support.
(6) Use a transmission jack to support fuel tank.
Remove bolts from fuel tank straps.
(7) Lower tank slightly.
(8) Disconnect the fuel filler vent tube. Squeeze
tabs and pull apart (Fig. 19).
Fig. 18 Fuel Tank
1 - ROLLOVER VALVE
2 - FUEL FILLER INLET
3 - ROLLOVER VALVE
4 - FUEL PUMP MODULE
14 - 12 FUEL DELIVERYRS
FUEL RAIL (Continued)
1 second. Therefore, battery voltage is not supplied to
the fuel pump, ignition coil, fuel injectors and heated
oxygen sensors.
ENGINE START-UP MODE
This is an OPEN LOOP mode. If the vehicle is in
park or neutral (automatic transaxles) or the clutch
pedal is depressed (manual transaxles) the ignition
switch energizes the starter relay when the engine is
not running. The following actions occur when the
starter motor is engaged.
²If the PCM receives the camshaft position sensor
and crankshaft position sensor signals, it energizes
the Auto Shutdown (ASD) relay and fuel pump relay.
If the PCM does not receive both signals within
approximately one second, it will not energize the
ASD relay and fuel pump relay. The ASD and fuel
pump relays supply battery voltage to the fuel pump,
fuel injectors, ignition coil, (EGR solenoid and PCV
heater if equipped) and heated oxygen sensors.
²The PCM energizes the injectors (on the 69É
degree falling edge) for a calculated pulse width until
it determines crankshaft position from the camshaft
position sensor and crankshaft position sensor sig-
nals. The PCM determines crankshaft position within
1 engine revolution.
²After determining crankshaft position, the PCM
begins energizing the injectors in sequence. It adjusts
injector pulse width and controls injector synchroni-
zation by turning the individual ground paths to the
injectors On and Off.
²When the engine idles within 64 RPM of its
target RPM, the PCM compares current MAP sensor
value with the atmospheric pressure value received
during the Ignition Switch On (zero RPM) mode.
Once the ASD and fuel pump relays have been
energized, the PCM determines injector pulse width
based on the following:
²MAP
²Engine RPM
²Battery voltage
²Engine coolant temperature
²Inlet/Intake air temperature (IAT)
²Throttle position
²The number of engine revolutions since cranking
was initiated
During Start-up the PCM maintains ignition tim-
ing at 9É BTDC.
ENGINE WARM-UP MODE
This is an OPEN LOOP mode. The following inputs
are received by the PCM:
²Manifold Absolute Pressure (MAP)
²Crankshaft position (engine speed)
²Engine coolant temperature
²Inlet/Intake air temperature (IAT)²Camshaft position
²Knock sensor
²Throttle position
²A/C switch status
²Battery voltage
²Vehicle speed
²Speed control
²O2 sensors
The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.
The PCM adjusts ignition timing and engine idle
speed. Engine idle speed is adjusted through the idle
air control motor.
CRUISE OR IDLE MODE
When the engine is at operating temperature this
is a CLOSED LOOP mode. During cruising or idle
the following inputs are received by the PCM:
²Manifold absolute pressure
²Crankshaft position (engine speed)
²Inlet/Intake air temperature
²Engine coolant temperature
²Camshaft position
²Knock sensor
²Throttle position
²Exhaust gas oxygen content (O2 sensors)
²A/C switch status
²Battery voltage
²Vehicle speed
The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.
The PCM adjusts engine idle speed and ignition
timing. The PCM adjusts the air/fuel ratio according
to the oxygen content in the exhaust gas (measured
by the upstream and downstream heated oxygen sen-
sor).
The PCM monitors for engine misfire. During
active misfire and depending on the severity, the
PCM either continuously illuminates or flashes the
malfunction indicator lamp (Check Engine light on
instrument panel). Also, the PCM stores an engine
misfire DTC in memory, if 2nd trip with fault.
The PCM performs several diagnostic routines.
They include:
²Oxygen sensor monitor
²Downstream heated oxygen sensor diagnostics
during open loop operation (except for shorted)
²Fuel system monitor
²EGR monitor (if equipped)
²Purge system monitor
²Catalyst efficiency monitor
²All inputs monitored for proper voltage range,
rationality.
RSFUEL INJECTION14-23
FUEL INJECTION (Continued)
IDLE AIR CONTROL MOTOR
DESCRIPTION
The idle air control valve is mounted on the throt-
tle body. The PCM operates the idle air control valve
(Fig. 15) or (Fig. 16).
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:
²Off-idle dashpot
²Deceleration air flow control
²A/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:
²Gear position
²ECT Sensor
²Battery voltage
²Ambient/Battery Temperature Sensor
²VSS
²TPS
²MAP Sensor
REMOVAL
When servicing throttle body components, always
reassemble components with new O-rings and seals
where applicable. If assembly of component is diffi-
cult, a light coat of engine oil may be applied to the
O-RINGS ONLY to aid assembly. Use care when
removing hoses to prevent damage to hose or hose
nipple.
(1) Disconnect negative cable from battery.
(2) Remove electrical connector from idle air con-
trol valve (Fig. 17).
(3) Remove idle air control valve mounting screw.
(4) Remove valve from throttle body. Ensure the
O-rings is removed with the valve.
INSTALLATION
When servicing throttle body components, always
reassemble components with new O-rings and seals
where applicable. If assembly of component is diffi-
cult,a light coat of engine oil may be applied to
the O-RINGS ONLY (Fig. 18)to aid assembly. Use
care when removing hoses to prevent damage to hose
or hose nipple.
(1) Carefully place idle air control motor into
throttle body.
Fig. 15 TPS/IAC 2.4L
1 - Idle Air Control Valve
2 - Throttle Position Sensor
Fig. 16 TPS/IAC 3.3/3.8L
1 - Idle Air Control Valve
2 - Throttle Position Sensor
RSFUEL INJECTION14-33