(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)
(9)The fuel pump module electrical connec-
tor has a retainer that locks it in place..Slide
fuel pump module electrical connector lock to unlock
(Fig. 27), (Fig. 28).
(10) Push down on connector retainer disconnect
the electrical connector.
(11) Lower tank slightly.
(12) Remove fuel filler vent tube from frame (Fig.
29).
(13) Lower tank from vehicle.
INSTALLATION
INSTALLATION
(1) Position fuel tank on transmission jack. Con-
nect check valve hose. Connect fuel filler tube vent
hose to fuel filler tube.
(2) Feed filler vent line thru frame rail.
(3) Raise tank into position and carefully work fuel
filler metal tube into the rubber hose on fuel tank. A
light coating of clean engine oil on the tube end may
be used to aid assembly.
(4) Tighten strap bolts to 54 N´m (40 ft. lbs.)
torque. Tighten T strap bolt to 28.2 N´m (250 in.
lbs.). Remove transmission jack.
(5) Tighten filler hose clamp to 3.3 N´m (30 in.
lbs.).
CAUTION: Ensure straps are not twisted or bent
before or after tightening strap screws.
(6) Connect fuel pump/module electrical connector.
Place retainer in locked position.
(7) Lubricate the fuel supply line with clean 30
weight engine oil, install the quick connect fuel fit-
ting. Refer to Tube/Fitting Assembly in the Fuel
Delivery section of this section.
(8) Connect the control vapor lines at front of
tank.
(9) Pull-pull-push on all connections to make sure
of connection.
(10) Fill fuel tank, replace cap, and connect bat-
tery negative cable.
(11) Use the DRBIIItscan tool to pressurize the
fuel system. Check for leaks.Fig. 27 ELECTRICAL CONNECTION
Fig. 28 ELECTRICAL CONNECTION REMOVED
Fig. 29 FILLER TUBE VENT LINE THRU RAIL
RSFUEL DELIVERY14-15
FUEL TANK (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
present (caused by a lean air/fuel mixture, can be
caused by misfire and exhaust leaks), the sensors
produces a low voltage. When there is a lesser
amount of oxygen present (caused by a rich air/fuel
mixture, can be caused by internal engine problems)
it produces a higher voltage. By monitoring the oxy-
gen content and converting it to electrical voltage,
the sensors act as a rich-lean switch.
The oxygen sensors are equipped with a heating
element that keeps the sensors at proper operating
temperature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into closed loop operation sooner.
Also, it allows the system to remain in closed loop
operation during periods of extended idle.
In Closed Loop operation the PCM monitors the O2
sensors input (along with other inputs) and adjusts
the injector pulse width accordingly. During Open
Loop operation the PCM ignores the O2 sensor input.
The PCM adjusts injector pulse width based on pre-
programmed (fixed) values and inputs from other
sensors.
NGC Controller - Has a common ground for the
heater in the O2S. 12 volts is supplied to the heater
in the O2S by the NGC controller. Both the upstream
and downstream O2 sensors for NGC are pulse width
modulation (PWM).NOTE: When replacing an O2
Sensor, the PCM RAM memory must be cleared,
either by disconnecting the PCM C-1 connector or
momentarily disconnecting the Battery negative ter-
minal. The NGC learns the characteristics of each O2
heater element and these old values should be
cleared when installing a new O2 sensor. The cus-
tomer may experience driveability issues if this is not
performed.
UPSTREAM OXYGEN SENSOR
The input from the upstream heated oxygen sensor
tells the PCM the oxygen content of the exhaust gas.
Based on this input, the PCM fine tunes the air-fuel
ratio by adjusting injector pulse width.
The sensor input switches from 2.5 to 3.5 volt,
depending upon the oxygen content of the exhaust
gas in the exhaust manifold. When a large amount ofoxygen is present (caused by a lean air-fuel mixture),
the sensor produces voltage as low as 2.5 volt. When
there is a lesser amount of oxygen present (rich air-
fuel mixture) the sensor produces a voltage as high
as 3.5 volt. By monitoring the oxygen content and
converting it to electrical voltage, the sensor acts as
a rich-lean switch.
The heating element in the sensor provides heat to
the sensor ceramic element. Heating the sensor
allows the system to enter into closed loop operation
sooner. Also, it allows the system to remain in closed
loop operation during periods of extended idle.
In Closed Loop, the PCM adjusts injector pulse
width based on the upstream heated oxygen sensor
input along with other inputs. In Open Loop, the
PCM adjusts injector pulse width based on prepro-
grammed (fixed) values and inputs from other sen-
sors.
DOWNSTREAM OXYGEN SENSOR
The downstream heated oxygen sensor input is
used to detect catalytic convertor deterioration. As
the convertor deteriorates, the input from the down-
stream sensor begins to match the upstream sensor
input except for a slight time delay. By comparing
the downstream heated oxygen sensor input to the
input from the upstream sensor, the PCM calculates
catalytic convertor efficiency. Also used to establish
the upstream O2 goal voltage (switching point).
REMOVAL
REMOVAL - UPSTREAM 1/1 - 2.4L
(1) Disconnect the negative battery cable.
(2) Raise and support the vehicle.
(3) Disconnect the electrical connector (Fig. 23).
(4) Use a socket such as the Snap-OntYA8875 or
equivalent to remove the sensor
(5) When the sensor is removed, the threads must
be cleaned with an 18 mm X 1.5 + 6E tap. If using
the original sensor, coat the threads with Loctite
771±64 anti-seize compound or equivalent.
RSFUEL INJECTION14-37
O2 SENSOR (Continued)
CONDITION POSSIBLE CAUSES CORRECTION
SUCKING AIR SOUND 1. Loose clamp on power steering
fluid return hose.1. Tighten or replace hose clamp.
2. Missing O-Ring on power steering
hose connection.2. Inspect connection and replace
O-Ring as required.
3. Low power steering fluid level. 3. Fill power steering fluid reservoir to
proper level and check for leaks.
4. Loose clamp on fluid supply hose. 4. Tighten or replace hose clamp.
SQUEAK OR RUBBING
SOUND1. Steering column shroud rubbing. 1. Realign shrouds as necessary.
2. Steering column shaft rubbing. 2. Move or realign item rubbing shaft.
3. Clockspring noisy. 3. Remove clockspring. Reinstall wheel.
If noise is gone, replace clockspring.
4. Seal lubrication inadequate. 4. Lube seal (if external).
5. Steering gear internally noisy. 5. Replace steering gear (if no other
cause can be found).
SCRUBBING OR
KNOCKING NOISE.1. Incorrect tire or wheel size. 1. Replace incorrect size tire or wheel
with size used as original equipment.
2. Interference between steering
gear and other vehicle components.2. Check for bent or misaligned
components and correct as necessary.
3. Steering gear internal stops worn
excessively allowing tires to be
steered excessively far.3. Replace steering gear.
* NOTE: There is some noise in all power steering
systems. One of the most common is a hissing
sound evident when turning the steering wheel
when at a standstill or when parking and the steer-
ing wheel is at the end of its travel. Hiss is a very
high frequency noise similar to that experienced
while slowly closing a water tap. The noise is
present in every valve and results when high veloc-
ity fluid passes valve orifice edges. There is no
relationship between this noise and the perfor-
mance of the steering system.** NOTE: A light clunk may be felt or heard during
steering wheel reversal while vehicle is stationary.
This results from internal steering gear rack move-
ment at the bushings and in no way affects the per-
formance of the steering system. This movement
may be felt in the steering components during
steering wheel reversal.
*** NOTE: Power steering pump growl/moan/groan
results from the development of high pressure fluid
flow. Normally this noise level should not be high
enough to be objectionable.
RSSTEERING19-5
STEERING (Continued)
Read the fluid level through the side of the power
steering fluid reservoir. The fluid level should indi-
cateªFILL RANGEºwhen the fluid is at a temper-
ature of approximately 21ÉC to 27ÉC (70ÉF to 80ÉF).
(1) Wipe the filler cap and area clean, then remove
the cap.
(2) Fill the fluid reservoir to the proper level and
let the fluid settle for at least two (2) minutes.
(3) Start the engine and let run for a few seconds,
then turn the engine off.
(4) Add fluid if necessary. Repeat the above steps
until the fluid level remains constant after running
the engine.
(5) Raise the front wheels off the ground.
(6) Start the engine.
(7) Slowly turn the steering wheel right and left,
lightly contacting the wheel stops.
(8) Add fluid if necessary.
(9) Lower the vehicle, then turn the steering wheel
slowly from lock-to-lock.
(10) Stop the engine. Check the fluid level and
refill as required.
(11) If the fluid is extremely foamy, allow the vehi-
cle to stabilize a few minutes, then repeat the above
procedure.
REMOVAL
REMOVAL - PUMP (2.4L ENGINE)
(1) Remove the (-) negative battery cable from the
battery and isolate cable.
(2) Remove the cap from the power steering fluid
reservoir.
(3) Using a siphon pump, remove as much power
steering fluid as possible from the power steering
fluid reservoir.
(4) Raise the vehicle on jack stands or centered on
a frame contact type hoist. See Hoisting in Lubrica-
tion and Maintenance.
(5) Disconnect the oxygen sensor wiring harness
from the vehicle wiring harness at the rear engine
mount bracket.
NOTE: The exhaust system needs to be removed
from the engine to allow for an area to remove the
power steering pump from the vehicle.(6) Remove the four bolts and flag nuts securing
the catalytic converter from the exhaust manifold
(Fig. 3).
(7) Disconnect all the exhaust system isolators/
hangers from the brackets on the exhaust system (2
at the mufflers and 1 at the resonator) (Fig. 4).
(8) Remove the exhaust system by moving it as far
rearward, then lowering the front below the cross-
member and out of the vehicle.
(9) Remove the power steering fluid supply hose
from the fitting on the power steering pump. Drain
off excess power steering fluid from hose.
(10) Move the heat sleeve on the power steering
return hose to expose the hose connection at the
pump (Fig. 5). Remove the hose from the power
steering Pump. Allow the remaining power steering
fluid to drain from the power steering pump and res-
ervoir through the removed return hose.
(11) Remove the power steering fluid pressure line
from the power steering pump (Fig. 6). Drain excess
power steering fluid from tube.
Fig. 3 Catalytic Converter to Exhaust Manifold
1 - CATALYTIC CONVERTER
2 - BOLT
3 - GASKET
4 - FLAG NUT
19 - 38 PUMPRS
PUMP (Continued)