No start DODGE NEON 2000 Service Repair Manual

(2) Install exhaust manifold support bracket (Fed-
eral and LEV only). Tighten M10 bolt to 54 N´m (40
ft. lbs.), M12 bolt to 95 N´m (70 ft. lbs.), and nut to
28 N´m (250 in. lbs.).
(3) Install bolt attaching manifold support bracket
to the heat shield (Federal and LEV only). Tighten
bolt to 28 N´m (250 in. lbs.).
(4) Assemble muffler and exhaust pipe to catalytic
converter. Install muffler and pipe support isolators
to the underbody.
(5) Tighten the catalytic converter to exhaust man-
ifold fasteners to 28 N´m (250 in. lbs.) (Fig. 11) or
(Fig. 12).
(6) Working from the front of the systemÐalign
each component to maintain position and proper
clearance with under body components. Tighten all
slip joint band clamps to 47 N´m (35 ft. lbs.).
CAUTION: Band (Torca) clamps should never be
tightened such that the two sides of the clamps are
bottomed out against the center hourglass shaped
center block. Once this occurs, the clamp has lost
clamping force and must be replaced.
(7) If removed, install downstream oxygen sensor.
(8) Connect downstream oxygen sensor electrical
connector.
CLEANING AND INSPECTION
EXHAUST SYSTEM
Inspect the exhaust pipes, catalytic converters,
muffler, and resonators for cracked joints, broken
welds and corrosion damage that would result in a
leaking exhaust system. Inspect the clamps, support
brackets, and insulators for cracks and corrosion
damage.
NOTE: Slip joint band clamps are spot welded to
exhaust system. If a band clamp must be replaced,
the spot weld must be ground off.
ADJUSTMENTS
EXHAUST SYSTEM ALIGNMENT
A misaligned exhaust system is usually indicated
by a vibration, rattling noise, or binding of exhaust
system components. These noises are sometimes hard
to distinguish from other chassis noises. Inspect
exhaust system for broken or loose clamps, heat
shields, insulators, and brackets. Replace or tighten
as necessary. It is important that exhaust system
clearances and alignment be maintained.
Perform the following procedures to align the
exhaust system. Refer to (Fig. 9) for clearance speci-
fications:
(1) Loosen clamps and support brackets.
(2) Align the exhaust system starting at the front,
working rearward.
(3) Tighten all clamps and brackets once align-
ment and clearances are achieved.
SPECIFICATIONS
TORQUE SPECIFICATION CHART
Fig. 12 Catalytic Converter to Exhaust Manifold
ConnectionÐULEV
1 ± PRESSED-IN NUTS
2 ± GASKET
3 ± BOLTS
DESCRIPTION N´m Ft.
Lbs.In.
Lbs.
Band ClampsÐFastener 47 35 Ð
Catalytic Converter to Exhaust
Manifold FlangeÐFasteners28 Ð 250
11 - 8 EXHAUST SYSTEMPL
REMOVAL AND INSTALLATION (Continued)

(3) Start the two rear crossmember mounting bolts
into the tapping plates mounted in the body. The
right side bolt can be viewed in the mounting bolt
figure (Fig. 5). The left side bolt is located in the
same location on the other side of the vehicle. Next,
install the two front mounting bolts attaching front
suspension crossmember to frame rails of vehicle.
Lightly tighten all four mounting bolts to a approxi-
mately 2 N´m (20 in. lbs.) to hold the front suspen-
sion crossmember in position.
NOTE: When reinstalling the front suspension
crossmember back in the vehicle, it is very impor-
tant that the crossmember be attached to the body
in exactly the same spot as when it was removed.
Otherwise, the vehicle's wheel alignment settings
(caster and camber) will be lost.
(4) Using a soft face hammer, tap the front suspen-
sion crossmember back-and-forth or side-to-side until
it is aligned with the previously scribed positioning
marks on the body of the vehicle (Fig. 6). Once the
front suspension crossmember is correctly positioned,
tighten the rear two crossmember mounting bolts to
a torque of 203 N´m (150 ft. lbs.), then tighten the
front two crossmember mounting bolts to a torque of
142 N´m (105 ft. lbs.).
(5) Tighten the lower control arm front pivot bolts
to a torque of 163 N´m (120 ft. lbs.).
(6) Attach the steering gear to the front suspen-
sion crossmember (Fig. 4). Install the four power
steering gear mounting bolts. Tighten the mounting
bolts to a torque of 61 N´m (45 ft. lbs.).
(7) Remove the wire or cord suspending the power
steering gear to the underbody.
(8) If the vehicle is equipped with a power steering
fluid cooler, install the two screws securing the cooler
to the front suspension crossmember. They are
located behind the cooler.
(9)
Install each ball joint stud into the steering
knuckle aligning the bolt hole in the knuckle boss with
the notch formed in the side of the ball joint stud.
(10) Install a new ball joint stud pinch bolt and
nut (Fig. 2). Tighten the nut to a torque of 95 N´m
(70 ft. lbs.).
(11) Fasten the engine torque strut to the right
forward corner of the front suspension crossmember
using its mounting bolt (Fig. 5). Follow the procedure
described in the ENGINE service manual group to
properly align and tighten the torque strut and it's
mounting bolts.
NOTE: Before installing the stabilizer bar, make
sure the bar is not upside-down. The stabilizer bar
must be installed with the curve on the outboard
ends of the bar facing downward to clear the con-
trol arms once fully installed (Fig. 7).(12)
First, place the stabilizer bar in position on the
front suspension crossmember. The slits in each cush-
ion must point toward the front of the vehicle and sit
directly on top of the raised beads formed into the
stamping on the crossmember. Next, install the cush-
ion retainers, matching the raised beads formed into
the cushion retainers to the grooves formed into the
cushions. Install the cushion retainer bolts, but do not
completely tighten them at this time.
(13) Install both stabilizer bar links back on vehi-
cle (Fig. 1). Start each stabilizer bar link bolt with
bushing from the bottom, through the stabilizer bar,
inner link bushings, lower control arm, and into the
upper retainer/nut and bushing. Do not fully tighten
the link assemblies at this time.
(14) Install the tire and wheel assemblies back on
vehicle. Tighten the wheel mounting nuts to 135 N´m
(100 ft. lbs.) torque.
(15) Lower the vehicle.
NOTE: It may be necessary to put the vehicle on a
platform hoist or alignment rack to gain access to
the stabilizer bar mounting bolts with the vehicle at
curb height.
(16) Tighten each stabilizer bar link by holding the
upper retainer/nut with a wrench and turning the
link bolt. Tighten each link bolt to a torque of 23
N´m (200 in. lbs.).
(17) Tighten the stabilizer bar cushion retainer
bolts to a torque of 34 N´m (300 in. lbs.).
(18) Check the front wheel alignment on the vehi-
cle. Refer to WHEEL ALIGNMENT in the SUSPEN-
SION service manual group.
Fig. 7 Downward Curve
1 ± STABILIZER BAR
2 ± LINK
3 ± DOWNWARD CURVE
4 ± CUSHION RETAINER
13 - 8 FRAME AND BUMPERSPL
REMOVAL AND INSTALLATION (Continued)

FUEL SYSTEM
TABLE OF CONTENTS
page page
FUEL DELIVERY SYSTEM.................... 1FUEL INJECTION SYSTEM.................. 21
FUEL DELIVERY SYSTEM
TABLE OF CONTENTS
page page
DESCRIPTION AND OPERATION
FUEL REQUIREMENTS.....................1
GASOLINE/OXYGENATE BLENDS.............2
FUEL DELIVERY SYSTEM...................3
FUEL PUMP MODULE......................3
ELECTRIC FUEL PUMP.....................4
FUEL GAUGE SENDING UNIT................4
FUEL FILTER/FUEL PRESSURE REGULATOR....4
FUEL TANK..............................4
FUEL RAIL...............................4
FUEL INJECTORS.........................5
PRESSURE-VACUUM FILLER CAP............5
ONBOARD REFUELING VAPOR RECOVERY....6
CONTROL VALVE/PRESSURE RELIEF.........6
QUICK-CONNECT FITTINGS.................6
ROLLOVER VALVES.......................7
FUEL TUBES/LINES/HOSES AND CLAMPS......8
SERVICE PROCEDURES
FUEL SYSTEM PRESSURE RELEASE
PROCEDURE...........................8INJECTOR CONNECTOR....................8
DRAINING FUEL TANK.....................9
HOSES AND CLAMPS......................9
QUICK-CONNECT FITTINGS.................9
REMOVAL AND INSTALLATION
AUTOMATIC SHUTDOWN RELAY............12
FUEL PUMP RELAY.......................12
FUEL PUMP MODULE.....................12
FUEL FILTER / PRESSURE REGULATOR......13
FUEL PUMP INLET STRAINER..............14
FUEL LEVEL SENSOR.....................14
FUEL INJECTORS........................15
FUEL TANK.............................16
FUEL FILLER NECK.......................17
ACCELERATOR PEDAL....................18
THROTTLE CABLE.......................19
SPECIFICATIONS
TORQUE...............................20
DESCRIPTION AND OPERATION
FUEL REQUIREMENTS
OPERATION
Your engine is designed to meet all emissions reg-
ulations and provide excellent fuel economy and per-
formance when using high quality unleaded gasoline
having an octane rating of 87. The use of premium
gasoline is not recommended. The use of premium
gasoline will provide no benefit over high quality reg-
ular gasoline, and in some circumstances may result
in poorer performance.
Light spark knock at low engine speeds is not
harmful to your engine. However, continued heavyspark knock at high speeds can cause damage and
immediate service is required. Engine damage result-
ing from operation with a heavy spark knock may
not be covered by the new vehicle warranty.
Poor quality gasoline can cause problems such as
hard starting, stalling and hesitations. If you experi-
ence these symptoms, try another brand of gasoline
before considering service for the vehicle.
The American Automobile Manufacturers Associa-
tion, AAMA, has issued gasoline specifications to
define the minimum fuel properties necessary to
deliver enhanced performance and durability for your
vehicle. DaimlerChrysler Corporation recommends
the use of gasoline that meet the AAMA specifica-
tions if they are available.
PLFUEL SYSTEM 14 - 1

carbon monoxide emissions. The type and amount of
oxygenate used in the blend is important.
The following are generally used in gasoline
blends:
Ethanol- (Ethyl or Grain Alcohol) properly
blended, is used as a mixture of 10 percent ethanol
and 90 percent gasoline. Gasoline blended with etha-
nol may be used in your vehicle.
MTBE/ETBE- Gasoline and MTBE (Methyl Ter-
tiary Butyl Ether) blends are a mixture of unleaded
gasoline and up to 15 percent MTBE. Gasoline and
ETBE (Ethyl Tertiary Butyl Ether) are blends of gas-
oline and up to 17 percent ETBE. Gasoline blended
with MTBE or ETBE may be used in your vehicle.
Methanol- Methanol (Methyl or Wood Alcohol) is
used in a variety of concentrations blended with
unleaded gasoline. You may encounter fuels contain-
ing 3 percent or more methanol along with other
alcohols called cosolvents.
DO NOT USE GASOLINE CONTAINING
METHANOL.
Use of methanol/gasoline blends may result in
starting and driveability problems and damage criti-
cal fuel system components.
Problems that are the result of using methanol/
gasoline blends are not the responsibility of
DaimlerChrysler Corporation and may not be covered
by the vehicle warranty.
Reformulated Gasoline
Many areas of the country are requiring the use of
cleaner-burning fuel referred to asReformulated
Gasoline. Reformulated gasoline are specially
blended to reduce vehicle emissions and improve air
quality.
DaimlerChrysler Corporation strongly supports the
use of reformulated gasoline whenever available.
Although your vehicle was designed to provide opti-
mum performance and lowest emissions operating on
high quality unleaded gasoline, it will perform
equally well and produce even lower emissions when
operating on reformulated gasoline.
Materials Added to Fuel
Indiscriminate use of fuel system cleaning agents
should be avoided. Many of these materials intended
for gum and varnish removal may contain active sol-
vents of similar ingredients that can be harmful to
fuel system gasket and diaphragm materials.
FUEL DELIVERY SYSTEM
OPERATION
The fuel delivery system consists of: the electric
fuel pump, fuel filter/fuel pressure regulator, fuel
tubes/lines/hoses, fuel rail, fuel injectors, fuel tank,
accelerator pedal and throttle cable.A fuel return system is used on all models (all
engines). Fuel is returned through the fuel pump
module and back into the fuel tank through the fuel
filter/fuel pressure regulator. A separate fuel return
line from the engine to the tank is no longer used
with any engine.
The fuel tank assembly consists of: the fuel tank,
filler tube, fuel gauge sending unit/electric fuel pump
module, a rollover valve(s) and a pressure-vacuum
filler cap.
Also to be considered part of the fuel system is the
evaporation control system or Onboard Refueling
Vapor recovery (ORVR). This is designed to reduce
the emission of fuel vapors into the atmosphere. The
description and function of the Evaporative Control
System is found in the Emission Control Systems
section.
FUEL PUMP MODULE
DESCRIPTION
The fuel pump module is installed in the fuel tank
(Fig. 1).
OPERATION
The fuel pump module contains the following:
²Electric fuel pump
²Fuel pump reservoir
²Inlet strainer
²Fuel filter/pressure regulator
²Fuel gauge sending unit
²Fuel supply line connection
Fig. 1 Fuel Pump Module
1 ± FUEL FILTER/PRESSURE REGULATOR
2 ± FUEL LEVEL SENSOR
3 ± FUEL RESERVOIR
4 ± INLET STRAINER
5 ± FLOAT
PLFUEL SYSTEM 14 - 3
DESCRIPTION AND OPERATION (Continued)

The inlet strainer, fuel pressure regulator and fuel
level sensor are the only serviceable items. If the fuel
pump requires service, replace the fuel pump module.
ELECTRIC 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. The fuel pump relay provides voltage to the
fuel pump. The fuel pump has a maximum dead-
headed pressure output of approximately 880 kPa
(130 psi). The regulator adjusts fuel system pressure
to approximately 338 kPa (49 psi).
FUEL GAUGE SENDING UNIT
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari-
able resistor (track). The resistor track is used to
send electrical signals to the instrument cluster for
fuel gauge operation and are then transmitted to the
engine controller for OBDII emission requirements.
OPERATION
For fuel gauge operation:As fuel level
increases, the float and arm move up. This increases
the sending unit resistance, causing the fuel gauge to
read full. As fuel level decreases, the float and arm
move down. This decreases the sending unit resis-
tance causing the fuel gauge to read empty.
After this fuel level signal is sent to the instru-
ment cluster, the instrument cluster will transmit
the data across the J1850 bus circuit to the PCM.
For OBD II emission requirements:The voltage
signal is sent to the instrument cluster to indicate
fuel level. The cluster transmits the fuel level to the
PCM where it is used to prevent a false setting of
misfire and fuel system monitor trouble codes. This
occurs if the fuel level in the tank is less than
approximately 15 percent of its rated capacity.
FUEL FILTER/FUEL PRESSURE REGULATOR
DESCRIPTION
A combination fuel filter and fuel pressure regula-
tor is used on all gas powered engines. It is located
on the top of the fuel pump module. A separate frame
mounted fuel filter is not used.
OPERATION
Fuel Pressure Regulator Operation:The pres-
sure regulator is a mechanical device that is cali-
brated to maintain fuel system operating pressure of
approximately 338 kPa (49 psi) at the fuel injectors.
It contains a diaphragm, calibrated springs and a
fuel return valve. The internal fuel filter (Fig. 2) is
also part of the assembly.
Fuel is supplied to the filter/regulator by the elec-
tric fuel pump through an opening tube at the bot-
tom of filter/regulator.
The fuel pump module contains a check valve to
maintain some fuel pressure when the engine is not
operating. This will help to start the engine.
If fuel pressure at the pressure regulator exceeds
approximately 49 psi, an internal diaphragm closes
and excess fuel pressure is routed back into the tank
through the pressure regulator. A separate fuel
return line is not used with any gas powered engine.
FUEL TANK
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
rollover valves mounted into the top of the fuel tank
(or pump module).
An evaporation control system is connected to the
rollover valve(s) to reduce emissions of fuel vapors
into the atmosphere. When fuel evaporates 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. Certain models are also
equipped with a self-diagnosing system using a Leak
Detection Pump (LDP). Refer to the Emission Control
System for additional information.
FUEL RAIL
DESCRIPTION
The fuel rail supplies the necessary fuel to each
individual fuel injector and is mounted to the intake
manifold (Fig. 3).
14 - 4 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

WARNING: REMOVE FILLER CAP TO RELIEVE
TANK PRESSURE BEFORE REMOVING OR REPAIR-
ING FUEL SYSTEM COMPONENTS.
ONBOARD REFUELING VAPOR RECOVERY
OPERATION
The emission control principle used in the ORVR
system is that the fuel flowing into the filler tube
(appx. 1º I. D.) creates an aspiration effect which
draws air into the fill tube. During refueling, the fuel
tank is vented to the vapor canister to capture escap-
ing vapors. With air flowing into the filler tube, there
are no fuel vapors escaping to the atmosphere. Once
the refueling vapors are captured by the canister, the
vehicle's computer controlled purge system draws
vapor out of the canister for the engine to burn. The
vapors flow is metered by the purge solenoid so that
there is no or minimal impact on driveability or
tailpipe emissions.
As fuel starts to flow through the fill tube, it opens
the normally closed check valve and enters the fuel
tank. Vapor or air is expelled from the tank through
the control valve to the vapor canister. Vapor is
absorbed in the canister until vapor flow in the lines
stops, either following shut-off or by having the fuel
level in the tank rise high enough to close the control
valve. The control valve contains a float that rises to
seal the large diameter vent path to the canister. At
this point in the fueling of the vehicle, the tank pres-
sure increase, the check valve closes (preventing tank
fuel from spiting back at the operator), and fuel then
rises up the filler tube to shut-off the dispensing noz-
zle.If the engine is shut-off while the On-Board diag-
nostics test is running, low level tank pressure can
be trapped in the fuel tank and fuel can not be added
to the tank until the pressure is relieved. This is due
to the leak detection pump closing the vapor outlet
from the top of the tank and the one-way check valve
not allowing the tank to vent through the fill tube to
atmosphere. Therefore, when fuel is added, it will
back-up in the fill tube and shut off the dispensing
nozzle. The pressure can be eliminated in two ways:
1. Vehicle purge must be activated and for a long
enough period to eliminate the pressure. 2. Removing
the fuel cap and allowing enough time for the system
to vent thru the recirulation tube.
CONTROL VALVE/PRESSURE RELIEF
OPERATION
If the fuel tank should over-pressurize, the control
valve incorporates a pressure relief port that allows
pressure relief capability under extreme conditions.
Example, if the canister vent line was to get pinched
or obstructed, the relief valve would vent the pres-
sure.
QUICK-CONNECT FITTINGS
DESCRIPTION
Different types of quick-connect fittings are used to
attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type. Some are equipped with safety latch clips.
Refer to the Removal/Installation section for more
information.
CAUTION: The interior components (o-rings, spac-
ers) of quick-connect fitting are not serviced sepa-
rately. Do not attempt to repair damaged fittings or
fuel lines/tubes. If repair is necessary, replace the
complete fuel tube assembly.
Fuel tubes connect fuel system components with
plastic quick-connect fuel fittings. The fitting con-
tains non-serviceable O-ring seals (Fig. 6).
CAUTION: Quick-connect fittings are not serviced
separately. Do not attempt to repair damaged quick-
connect fittings or fuel tubes. Replace the complete
fuel tube/quick-connect fitting assembly.
The quick-connect fitting consists of the O-rings,
retainer and casing (Fig. 6). When the fuel tube
enters the fitting, the retainer locks the shoulder of
the nipple in place and the O-rings seal the tube.
Fig. 5 Fuel Injector
1 ± FUEL INJECTOR
2 ± NOZZLE
3 ± TOP (FUEL ENTRY)
14 - 6 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

FUEL TUBES/LINES/HOSES AND CLAMPS
OPERATION
Also refer to Quick-Connect Fittings.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
SYSTEM PRESSURE RELEASE PROCEDURE IN
THIS GROUP.
Inspect all hose connections such as clamps, cou-
plings and fittings to make sure they are secure and
leaks are not present. The component should be
replaced immediately if there is any evidence of deg-
radation that could result in failure.
Never attempt to repair a plastic fuel line/tube.
Replace as necessary.
Avoid contact of any fuel tubes/hoses with other
vehicle components that could cause abrasions or
scuffing. Be sure that the plastic fuel lines/tubes areproperly routed to prevent pinching and to avoid heat
sources.
The lines/tubes/hoses used on fuel injected vehicles
are of a special construction. This is due to the
higher fuel pressures and the possibility of contami-
nated fuel in this system. If it is necessary to replace
these lines/tubes/hoses, only those marked EFM/EFI
may be used.
If equipped:The hose clamps used to secure rub-
ber hoses on fuel injected vehicles are of a special
rolled edge construction. This construction is used to
prevent the edge of the clamp from cutting into the
hose. Only these rolled edge type clamps may be
used in this system. All other types of clamps may
cut into the hoses and cause high-pressure fuel leaks.
Use new original equipment type hose clamps.
Tighten hose clamps to 3 N´m (25 in. lbs.) torque.
SERVICE PROCEDURES
FUEL SYSTEM PRESSURE RELEASE
PROCEDURE
(1) Remove Fuel Pump relay from Power Distribu-
tion Center (PDC). For location of relay, refer to label
on underside of PDC cover.
(2) Start and run engine until it stalls.
(3) Attempt restarting engine until it will no
longer run.
(4) Turn ignition key to OFF position.
CAUTION: Steps 1, 2, 3 and 4 must be performed to
relieve high pressure fuel from within fuel rail. Do
not attempt to use following steps to relieve this
pressure as excessive fuel will be forced into a cyl-
inder chamber.
(5) Place a rag or towel below fuel line quick-con-
nect fitting at fuel rail.
(6) Return fuel pump relay to PDC.
(7) One or more Diagnostic Trouble Codes (DTC's)
may have been stored in PCM memory due to fuel
pump relay removal. The DRB IIItscan tool must be
used to erase a DTC.
INJECTOR CONNECTOR
REMOVAL
(1) Disconnect electrical connectors at the fuel
injectors. To remove connector refer to (Fig. 8). Pull
the red colored slider away from injector (1). While
pulling the slider, depress tab (2) and remove connec-
tor (3) from injector. The factory fuel injection wiring
harness is numerically tagged (INJ 1, INJ 2, etc.) for
injector position identification. If harness is not
tagged, make note of wiring location before removal.
Fig. 6 Plastic Quick-Connect Fittings
1 ± CASING
2 ± WINDOW
3 ± RETAINER TAB
4 ± NIPPLE
5 ± O RINGS
6 ± WINDOW
7 ± RETAINER ªEARº
14 - 8 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

being serviced. The plastic retainer will remain on
component being serviced after fitting is discon-
nected. The O-rings and spacer will remain in quick-
connect fitting connector body.
(5) Inspect quick-connect fitting body and compo-
nent for damage. Replace as necessary.
CAUTION:
When the quick-connect fitting was dis-
connected, the plastic retainer will remain on the com-
ponent being serviced. If this retainer must be
removed, very carefully release the retainer from the
component with two small screwdrivers. After removal,
inspect the retainer for cracks or any damage.
(6) Prior to connecting quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean parts with a lint-free cloth.
Lubricate with clean engine oil.
(7) Insert quick-connect fitting to component being
serviced and into plastic retainer. When a connection
is made, a click will be heard.
(8) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(9) Connect negative cable to battery or auxiliary
jumper terminal.
(10) Start engine and check for leaks.
PLASTIC RETAINER RING TYPE FITTING
This type of fitting can be identified by the use of a
full-round plastic retainer ring (Fig. 11) usually black
in color.
CAUTION: The interior components (O-rings, spac-
ers, retainers) of this type of quick-connect fitting
are not serviced separately. Do not attempt to repair
damaged fittings or fuel lines/tubes. If repair is nec-
essary, replace the complete fuel tube assembly.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
SYSTEM PRESSURE RELEASE PROCEDURE IN
THIS GROUP.
DISCONNECTION/CONNECTION
(1) Perform fuel pressure release procedure. Refer
to Fuel Pressure Release Procedure in this section.
(2) Disconnect negative battery cable from battery
or auxiliary jumper terminal.
(3) Clean fitting of any foreign material before dis-
assembly.
(4) To release fuel system component from quick-
connect fitting, firmly push fitting towards compo-nent being serviced while firmly pushing plastic
retainer ring into fitting (Fig. 11). With plastic ring
depressed, pull fitting from component.The plastic
retainer ring must be pressed squarely into fit-
ting body. If this retainer is cocked during
removal, it may be difficult to disconnect fit-
ting. Use an open-end wrench on shoulder of
plastic retainer ring to aid in disconnection.
(5) After disconnection, plastic retainer ring will
remain with quick-connect fitting connector body.
(6) Inspect fitting connector body, plastic retainer
ring and fuel system component for damage. Replace
as necessary.
(7) Prior to connecting quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean parts with a lint-free cloth.
Lubricate with clean engine oil.
(8) Insert quick-connect fitting into component
being serviced until a click is felt.
(9) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(10) Connect negative battery cable to battery or
auxiliary jumper terminal.
(11) Start engine and check for leaks.
Fig. 11 Plastic Retainer Ring Type Fitting
1 ± FUEL TUBE
2 ± QUICK CONNECT FITTING
3 ± PUSH
4 ± PLASTIC RETAINER
5 ± PUSH
6 ± PUSH
7 ± PUSH
8 ± PUSH
PLFUEL SYSTEM 14 - 11
SERVICE PROCEDURES (Continued)

DESCRIPTION AND OPERATION
INJECTION SYSTEM
All engines used in this section have a sequential
Multi-Port Electronic Fuel Injection system. The MPI
system is computer regulated and provides precise
air/fuel ratios for all driving conditions. The Power-
train Control Module (PCM) operates the fuel injec-
tion system.
The PCM regulates:
²Ignition timing
²Air/fuel ratio
²Emission control devices
²Cooling fan
²Charging system
²Idle speed
²Vehicle speed control
Various sensors provide the inputs necessary for
the PCM to correctly operate these systems. In addi-
tion to the sensors, various switches also provide
inputs to the PCM.
All inputs to the PCM are converted into signals.
The PCM can adapt its programming to meet chang-
ing operating conditions.
Fuel is injected into the intake port above the
intake valve in precise metered amounts through
electrically operated injectors. The PCM fires the
injectors in a specific sequence. Under most operat-
ing conditions, the PCM maintains an air fuel ratio
of 14.7 parts air to 1 part fuel by constantly adjust-
ing injector pulse width. Injector pulse width is the
length of time the injector is open.
The PCM adjusts injector pulse width by opening
and closing the ground path to the injector. Engine
RPM (speed) and manifold absolute pressure (air
density) are the primary inputs that determine injec-
tor pulse width.
MODES OF OPERATION
OPERATION
As input signals to the PCM change, the PCM
adjusts its response to output devices. For example,
the PCM must calculate a different injector pulse
width and ignition timing for idle than it does for
Wide Open Throttle (WOT). There are several differ-
ent modes of operation that determine how the PCM
responds to the various input signals.
There are two different areas of operation, OPEN
LOOP and CLOSED LOOP.
During OPEN LOOP modes the PCM receives
input signals and responds according to preset PCM
programming. Inputs from the upstream and down-
stream heated oxygen sensors are not monitored dur-
ing OPEN LOOP modes, except for heated oxygensensor diagnostics (they are checked for shorted con-
ditions at all times).
During CLOSED LOOP modes the PCM monitors
the inputs from the upstream and downstream
heated oxygen sensors. The upstream heated oxygen
sensor input tells the PCM if the calculated injector
pulse width resulted in the ideal air-fuel ratio of 14.7
to one. By monitoring the exhaust oxygen content
through the upstream heated oxygen sensor, the
PCM can fine tune injector pulse width. Fine tuning
injector pulse width allows the PCM to achieve opti-
mum fuel economy combined with low emissions.
For the PCM to enter CLOSED LOOP operation,
the following must occur:
(1) Engine coolant temperature must be over 35ÉF.
²If the coolant is over 35É the PCM will wait 44
seconds.
²If the coolant is over 50ÉF the PCM will wait 38
seconds.
²If the coolant is over 167ÉF the PCM will wait
11 seconds.
(2) For other temperatures the PCM will interpo-
late the correct waiting time.
(3) O2 sensor must read either greater than 0.745
volts or less than 0.1 volt.
(4) The multi-port fuel injection systems has the
following modes of operation:
²Ignition switch ON (Zero RPM)
²Engine start-up
²Engine warm-up
²Cruise
²Idle
²Acceleration
²Deceleration
²Wide Open Throttle
²Ignition switch OFF
(5) The engine start-up (crank), engine warm-up,
deceleration with fuel shutoff and wide open throttle
modes are OPEN LOOP modes. Under most operat-
ing conditions, the acceleration, deceleration (with
A/C on), idle and cruise modes,with the engine at
operating temperatureare CLOSED LOOP modes.
IGNITION SWITCH ON (ZERO RPM) MODE
When the ignition switch activates the fuel injec-
tion system, the following actions occur:
²The PCM monitors the engine coolant tempera-
ture sensor and throttle position sensor input. The
PCM determines basic fuel injector pulse width from
this input.
²The PCM determines atmospheric air pressure
from the MAP sensor input to modify injector pulse
width.
When the key is in the ON position and the engine
is not running (zero rpm), the Auto Shutdown (ASD)
and fuel pump relays de-energize after approximately
14 - 22 FUEL SYSTEMPL

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. 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 and heated oxygen sen-
sors.
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 within664 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. If
the PCM does not detect a minimum difference
between the two values, it sets a MAP diagnostic
trouble code into memory.
Once the ASD and fuel pump relays have been
energized, the PCM determines injector pulse width
based on the following:
²Battery voltage
²Engine coolant temperature
²Engine RPM
²Intake 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:
²Engine coolant temperature
²Manifold Absolute Pressure (MAP)
²Intake air temperature (IAT)²Crankshaft position (engine speed)
²Camshaft position
²Knock sensor
²Throttle position
²A/C switch
²Battery voltage
²Power steering pressure switch
²Vehicle speed
²Speed control
²O2 sensors
²All diagnostics
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:
²Intake air temperature
²Engine coolant temperature
²Manifold absolute pressure
²Crankshaft position (engine speed)
²Camshaft position
²Knock sensor
²Throttle position
²Exhaust gas oxygen content
²A/C control positions
²Power steering pressure switch
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.
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
²Purge system monitor
PLFUEL SYSTEM 14 - 23
DESCRIPTION AND OPERATION (Continued)