
a catalytic converter. Failure of the catalytic con-
verter can occur due to temperature increases caused
by unburned fuel igniting when passing through the
converter.
The use of the catalysts also involves some non-au-
tomotive problems. Unleaded gasoline must be used
to avoid poisoning the catalyst core. Do not allow
engine to operate at fast idle for extended periods
(over 5 minutes). This condition may result in exces-
sive exhaust system and floor pan temperatures.
EXHAUST GAS RECIRCULATION (EGR)
To assist in the control of oxides of nitrogen (NOx)
in engine exhaust, all engines are equipped with an
exhaust gas recirculation system. The use of exhaust
gas to dilute incoming air/fuel mixtures lowers peak
flame temperatures during combustion, thus limiting
the formation of NOx.
Exhaust gases are taken from opening in the
exhaust manifold passage to the intake manifold.
REFER TO SECTION 25 FOR A COMPLETE
DESCRIPTION, DIAGNOSIS AND SERVICE PRO-
CEDURES ON THE EXHAUST GAS RECIRCULA-
TION SYSTEM AND COMPONENTS.
HEAT SHIELDS
Heat shields (Fig. 2) are needed to protect both the
vehicle and the floor pan from the high temperatures
developed near the catalytic converter and muffler.
Avoid application of rust prevention com-
pounds or undercoating materials to exhaust
system floor pan heat shields on cars so
equipped. Light over spray near the edges is
permitted. Application of coating will greatlyreduce the efficiency of the heat shields result-
ing in excessive floor pan temperatures and
objectionable fumes.
EXHAUST FLEX-JOINT COUPLING
A exhaust flex-joint coupling (Fig. 3) is used to
secure the catalytic converter to the engine manifold.
This living joint actually moves back and forth as the
engine moves, preventing breakage that could occur
from the back-and-forth motion of a transverse
mounted engine.
The exhaust flex-joint has four bolts, four flag nuts
and a gasket that are separate parts from the
exhaust flex-joint. The flex-joint is welded to the cat-
alytic converter.
Fig. 2 Heat Shields
Fig. 3 Flex-Joint
11 - 2 EXHAUST SYSTEM AND INTAKE MANIFOLDNS
GENERAL INFORMATION (Continued)

FUEL SYSTEM
CONTENTS
page page
FUEL DELIVERY SYSTEM................... 4
FUEL INJECTION SYSTEM................. 29GENERAL INFORMATION................... 1
GENERAL INFORMATION
INDEX
page page
GENERAL INFORMATION
CRUISING RANGE........................ 3
E-85 GENERAL INFORMATION.............. 2
ETHANOL FUEL (E-85).................... 2
FUEL REQUIREMENTS.................... 1
FUEL REQUIREMENTS.................... 2GASOLINE/OXYGENATE BLENDS............ 2
INTRODUCTION......................... 1
PCM REPLACEMENT..................... 1
REPLACEMENT PARTS.................... 3
STARTING.............................. 2
GENERAL INFORMATION
INTRODUCTION
Throughout this group, references may be made to
a particular vehicle by letter or number designation.
A chart showing the breakdown of these designations
is included in the Introduction Section at the front of
this service manual.
The Evaporation Control System, is also considered
part of the fuel system. The system reduces the emis-
sion of fuel vapor into the atmosphere.
The description and function of the Evaporation
Control System is found in Group 25 of this manual.
PCM REPLACEMENT
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW PCM WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE VEHICLES ORIGINAL MILEAGE. IF THIS
STEP IS NOT DONE A DIAGNOSTIC TROUBLE
CODE (DTC) MAY BE SET.
FUEL REQUIREMENTS
Your vehicle was designed to meet all emission reg-
ulations and provide excellent fuel economy when
using high quality unleaded gasoline.
Use unleaded gasolines having a minimum posted
octane of 87.
If your vehicle develops occasional light spark
knock (ping) at low engine speeds this is not harm-
ful. However; continued heavy knock at high speeds
can cause damage and should be reported to your
dealer immediately. Engine damage as a result of
heavy knock operation may not be covered by the
new vehicle warranty.
In addition to using unleaded gasoline with the
proper octane rating, those that contain detergents,
corrosion and stability additives are recommended.
Using gasolines that have these additives will help
improve fuel economy, reduce emissions, and main-
tain vehicle performance.
Poor quality gasoline can cause problems such as
hard starting, stalling, and stumble. If you experi-
ence these problems, try another brand of gasoline
before considering service for the vehicle.
NSFUEL SYSTEM 14 - 1

WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING QUICK-CONNECT FIT-
TINGS AT FUEL FILTER. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE.
REMOVAL
(1) Perform fuel system pressure release.
(2) Disconnect quick-connect fittings from fuel
pump module and chassis fuel supply tube. Refer to
Quick-Connect Fittings in this section.
(3) Remove filter retaining screw (Fig. 13) and
remove filter from tank.
INSTALLATION
(1) Install fuel filter to tank.
(2) The fuel supply (to filter) tube, return tube (to
pump module) and fuel supply (to chassis fuel line)
are permanently attached the fuel filter. The ends of
the fuel supply and return tubes have different size
quick-connect fittings.
(3) Apply a light coating of clean 30 weight engine
oil to the fuel filter nipples. Install fuel tubes. Refer
to Fuel Tubes and Quick-Connect Fittings in this sec-
tion.
FUEL PUMP MODULE
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.
WARNING: THE FUEL RESERVOIR OF THE FUEL
PUMP MODULE DOES NOT EMPTY OUT WHEN THE
TANK IS DRAINED. THE FUEL IN THE RESERVOIR
WILL SPILL OUT WHEN THE MODULE IS
REMOVED.
REMOVAL
(1) Remove fuel filler cap and perform Fuel Sys-
tem Pressure Release procedure.
(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.
(6) Use a transmission jack to support the fuel
tank. Remove bolts from fuel tank straps. Lower
tank slightly.
(7) Clean area around fuel tank module and tank
to keep dirt and foreign material out of tank.
(8) Disconnect fuel lines from fuel pump module by
depressing quick connect retainers with thumb and
fore finger (Fig. 14).
(9) Slide fuel pump module electrical connector
lock to unlock.
(10) Push down on connector retainer (Fig. 15) and
pull connector off module.
Fig. 13 Fuel Filter
Fig. 14 Fuel Line Retainers and Pump Connector
Lock
Fig. 15 Pump Module Connector Retainer and Lock
NSFUEL SYSTEM 14 - 13
REMOVAL AND INSTALLATION (Continued)

(11) Using Special Tool 6856, remove plastic lock-
nut counterclockwise to release pump module (Fig.
16).
(12) Carefully remove pump module and O-ring
from tank (Fig. 17).
(13) Discard old O-ring.INSTALLATION
(1) Wipe seal area of tank clean and place a new
O-ring seal in position on pump.
(2) Position fuel pump in tank with locknut.
(3) Tighten locknut to 53 N´m (43 ft. lbs.).
(4) Connect fuel lines.
(5) Plug in electrical connector. Slide connector
lock into position.
(6) Raise fuel tank, install bolts into fuel tank
straps and tighten.
(7) Lower vehicle on hoist.
(8) Connect negative cable from battery.
(9) Fill fuel tank. Check for leaks.
(10) Install fuel filler cap.
FUEL PRESSURE REGULATOR
The fuel pressure regulator is part of the fuel
pump module (Fig. 18). Remove the fuel pump mod-
ule from the fuel tank to access the fuel pressure reg-
ulator.
WARNING: FUEL SYSTEM PRESSURE MUST BE
RELEASED BEFORE SERVICING ANY FUEL SYS-
TEM COMPONENT. PERFORM THE FUEL SYSTEM
PRESSURE RELEASE PROCEDURE.
REMOVAL
(1) Spread tangs on pressure regulator retainer
(Fig. 18).
(2) Pry fuel pressure regulator out of housing.
(3) Ensure both upper and lower O-rings were
removed with regulator.
INSTALLATION
(1) Lightly lubricate the O-rings with clean engine
oil and place them into opening in pump module (Fig.
19).
(2) Push regulator into opening in pump module.
Fig. 16 Fuel Pump Module Lock Nut Removal
Fig. 17 Fuel Pump Module Removal
Fig. 18 Fuel Pressure Regulator
14 - 14 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

(4) Push level sensor signal and ground terminals
out of the connector (Fig. 24).
(5) Insert a screwdriver between the fuel pump
module and the top of the level sensor housing (Fig.
25). Push level sensor down slightly.
(6) Slide level sensor wires through opening fuel
pump module (Fig. 26).(7) Slide level sensor out of installation channel in
module.
INSTALLATION
(1) Insert level sensor wires into bottom of opening
in module.
(2) Wrap wires into groove in back of level sensor
(Fig. 27).
(3) While feeding wires into guide grooves, slide
level sensor up into channel until it snaps into place
(Fig. 28). Ensure tab at bottom of sensor locks in
place.
(4) Install level sensor wires in connector. Push
the wires up through the connector and then pull
them down until they lock in place. Ensure signal
and ground wires are installed in the correct posi-
tion.
(5) Install locking wedge on connector.
(6) Push connector up into bottom of fuel pump
module electrical connector.
Fig. 23 Wire Terminal Locking Finger
Fig. 24 Removing Wires From Connector
Fig. 25 Loosening Level Sensor
Fig. 26 Level Sensor Removal/Installation
Fig. 27 Groove in Back Side of Level Sensor
14 - 16 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

(7) Install fuel pump module. Refer to Fuel Pump
Module in this section.
FUEL TANK
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove fuel filler cap and perform Fuel Sys-
tem Pressure Release procedure.
(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.
(6) Disconnect both the fuel fill and fuel vent rub-
ber hoses at the fuel tank.(7) Disconnect fuel supply lines from the steel sup-
ply line.
The fuel pump module electrical connector
has a retainer that locks it in place.
(8) Slide fuel pump module electrical connector
lock to unlock (Fig. 29).
(9) Push down on connector retainer (Fig. 30) and
pull connector off module.
(10) Use a transmission jack to support fuel tank.
Remove bolts from fuel tank straps.
(11) Lower tank slightly. Carefully remove filler
hose from tank.
(12) Lower the fuel tank. Disconnect pressure
relief/rollover valve hose at the front of tank. Remove
clamp and remove fuel filler tube vent hose. Remove
fuel tank from vehicle.
Fig. 28 Installation Channel
Fuel Tank
Fig. 29 Fuel Line Retainers and Pump Connector
Lock
Fig. 30 Pump Module Connector Retainer and Lock
NSFUEL SYSTEM 14 - 17
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
(1) Position fuel tank on transmission jack. Con-
nect pressure relief/rollover valve hose. Connect fuel
filler tube vent hose and replace clamp.
(2) Raise tank into position and carefully work
filler tube into tank. A light coating of clean engine
oil on the tube end may be used to aid assembly.
(3) Feed filler vent line thru frame rail. Careful
not to cross lines.
(4) Tighten strap bolts to 54 N´m (40 ft. lbs.)
torque. 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 nuts.
(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 Group.
(8) Attach filler line to filler tube. Pull on connec-
tor to make sure of connection.
(9) Fill fuel tank, replace cap, and connect battery
negative cable.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(10) Use the DRB scan tool ASD Fuel System Test
to pressurize the fuel system. Check for leaks.
FUEL INJECTOR RAILÐ2.4L
REMOVAL
(1) Perform fuel system pressure release procedure
before servicing or starting repairs.Refer to
Fuel System Pressure Release Procedure in this sec-
tion.
(2) Disconnect negative cable from battery.
(3) Remove air cleaner inlet hose from throttle
body.
(4) Remove throttle cable and speed control cable
(if equipped) from throttle lever.
(5) Remove throttle cables from bracket by com-
pressing retaining tabs.
(6) Remove connector from throttle position sensor.
(7) Remove connector from idle air control motor.
(8) Remove vacuum lines from intake plenum fit-
tings (Fig. 31) and (Fig. 32).(9) Remove connector from intake air temperature
sensor (Fig. 32).
(10) Remove connector from MAP sensor (Fig. 33).
(11) Remove fuel hose quick connect fitting from
the chassis tube (Fig. 34).Refer to Fuel Hoses,
Clamps and Quick Connect Fittings in this Sec-
tion.Place a shop towel under the connections to
absorb any fuel spilled from the fitting.
Fig. 31 Vacuum Fitting on Rear of Intake Manifold
Fig. 32 Electrical and Vacuum Connections
14 - 18 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

The crankshaft position sensor is located in the
transaxle housing, above the vehicle speed sensor
(Fig. 10). The bottom of the sensor is positioned next
to the drive plate.The distance between the bot-
tom of sensor and the drive plate is critical to
the operation of the system. When servicing the
crankshaft position sensor, refer to the appro-
priate Multi-Port Fuel Injection Service Proce-
dures section in this Group.
2.4L
The second crankshaft counterweight has
machined into it two sets of four timing reference
notches and a 60 degree signature notch (Fig. 11).
From the crankshaft position sensor input the PCM
determines engine speed and crankshaft angle (posi-
tion).
The notches generate pulses from high to low in
the crankshaft position sensor output voltage. When
a metal portion of the counterweight aligns with the
crankshaft position sensor, the sensor output voltagegoes low (less than 0.3 volts). When a notch aligns
with the sensor, voltage spikes high (5.0 volts). As a
group of notches pass under the sensor, the output
voltage switches from low (metal) to high (notch)
then back to low.
If available, an oscilloscope can display the square
wave patterns of each voltage pulse. From the width
of the output voltage pulses, the PCM calculates
engine speed. The width of the pulses represent the
amount of time the output voltage stays high before
switching back to low. The period of time the sensor
output voltage stays high before switching back to
low is referred to as pulse width. The faster the
engine is operating, the smaller the pulse width on
the oscilloscope.
By counting the pulses and referencing the pulse
from the 60 degree signature notch, the PCM calcu-
lates crankshaft angle (position). In each group of
timing reference notches, the first notch represents
69 degrees before top dead center (BTDC). The sec-
ond notch represents 49 degrees BTDC. The third
notch represents 29 degrees. The last notch in each
set represents 9 degrees before top dead center
(TDC).
The timing reference notches are machined to a
uniform width representing 13.6 degrees of crank-
shaft rotation. From the voltage pulse width the
PCM tells the difference between the timing refer-
ence notches and the 60 degree signature notch. The
60 degree signature notch produces a longer pulse
width than the smaller timing reference notches. If
the camshaft position sensor input switches from
high to low when the 60 degree signature notch
passes under the crankshaft position sensor, the
PCM knows cylinder number one is the next cylinder
at TDC.
The crankshaft position sensor mounts to the
engine block behind the generator, just above the oil
filter (Fig. 12).
ENGINE COOLANT TEMPERATURE SENSORÐPCM
INPUT
The engine coolant temperature sensor is a vari-
able resistor with a range of -40ÉC to 129ÉC (-40ÉF to
265ÉF).
The engine coolant temperature sensor provides an
input voltage to the PCM. As coolant temperature
varies, the sensor resistance changes resulting in a
different input voltage to the PCM.
When the engine is cold, the PCM will demand
slightly richer air/fuel mixtures and higher idle
speeds until normal operating temperatures are
reached.
The engine coolant sensor is also used for cooling
fan control.
Fig. 10 Crankshaft Position Sensor LocationÐ3.0/
3.3/3.8L
Fig. 11 Timing Reference Notches
14 - 36 FUEL SYSTEMNS
DESCRIPTION AND OPERATION (Continued)