battery CHRYSLER VOYAGER 2004 Service Manual

FUEL DELIVERY
DESCRIPTION
The front wheel drive car uses a plastic fuel tank
located rear center of the vehicle.
The Fuel Delivery System consists of: the following
items:
²Electric fuel pump module
²Fuel filter
²Tubes/lines/hoses
²Fuel injectors
The in-tank fuel pump module contains the fuel
pump. The pump is serviced as part of the fuel pump
module. Refer to Fuel Pump Module.
The fuel filter is replaceable only as part of the
fuel pump module.
OPERATION
The fuel system provides fuel pressure by an
in-tank pump module. The Powertrain Control Mod-
ule (PCM) controls the operation of the fuel system
by providing battery voltage to the fuel pump
through the fuel pump relay. The PCM requires only
three inputs and a good ground to operate the fuel
pump relay. The three inputs are:
²Ignition voltage
²Crankshaft Position (CKP) sensor
²Camshaft Position (CMP) sensor
DIAGNOSIS AND TESTING - FUEL DELIVERY
SYSTEM
(Refer to Appropriate Diagnostic Information)
STANDARD PROCEDURE
STANDARD PROCEDURE - 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.
(5) Return fuel pump relay to PDC.
(6) 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.
STANDARD PROCEDURE - DRAINING FUEL
TANK
Two different procedures may be used to drain fuel
tank (lowering tank or using DRBIIItscan tool).The quickest draining procedure involves lowering
the 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. THIS MAY
RESULT IN PERSONAL INJURY OR DEATH.
As an alternative procedure, the electric fuel pump
may be activated allowing tank to be drained at fuel
rail connection. Refer to DRBIIItscan tool for fuel
pump activation procedures. Before disconnecting
fuel line at fuel rail, release fuel pressure. Refer to
the Fuel System Pressure Release Procedure in this
group for procedures. Disconnect the fuel line at the
fuel rail and remove the plastic retainer from the
fuel rail. Take plastic retainer and install it back into
the fuel line from body. Check the O-ring and make
sure that it is in place and not damaged. Attach end
of special test hose tool number 6539 at fuel line con-
nection from the body line. Position opposite end of
this hose tool to an approved gasoline draining sta-
tion. Activate fuel pump and drain tank until empty.
When done remove the special test hose tool number
6539 from the body line. Remove the plastic retainer
from the special test hose tool number 6539 and rein-
stall it into the fuel line from the body. Check the
O-ring and make sure that it is in place and not
damaged. Install the fuel line to the fuel rail.
If electric fuel pump is not operating, tank must be
lowered for fuel draining. Refer to following proce-
dures.
(1) Remove fuel filler cap.
(2) Perform the Fuel System Pressure Release pro-
cedure.
(3) Disconnect negative cable from battery.
(4) Raise vehicle and support.
(5) Certain models are equipped with a separate
grounding wire (strap) connecting the fuel fill tube
assembly to the body. Disconnect wire by removing
screw.
(6) Open fuel fill door and remove screws mount-
ing fuel filler tube assembly to body. Do not discon-
nect rubber fuel fill or vent hoses from tank at this
time.
(7) Place a transmission jack under center of fuel
tank. Apply a slight amount of pressure to fuel tank
with transmission jack.
(8) Remove fuel tank mounting straps.
(9)Lower the tank just enough so that the
filler tube fitting is the highest point of the fuel
tank.
(10) Remove filler tube from fuel tank. Tank will
be drained through this fitting.
14 - 2 FUEL DELIVERYRS

(5) Clean top of tank to remove loose dirt and
debris.
(6) Using a brass punch and hammer remove lock-
nut to release pump module (Fig. 10).
WARNING: THE FUEL RESERVOIR OF THE FUEL
PUMP MODULE DOES NOT EMPTY OUT WHEN THE
TANK IS DRAINED. THE FUEL IN THE RESERVOIR
MAY SPILL OUT WHEN THE MODULE IS REMOVED.
(7) Remove fuel pump module and O-ring from
tank (Fig. 11). Discard O-ring.
INSTALLATION
NOTE: Be careful not to allow dirt/debris to fall into
the fuel tank.
(1) Wipe seal area of tank clean and place a new
O-ring seal in position on pump.
(2) Position fuel pump module in tank.
(3) Tighten lockring using a brass punch and ham-
mer to install the lockring (Fig. 10).
(4) Install fuel tank, refer to the Fuel Tank instal-
lation section.
(5) Lower vehicle.
(6) Connect negative cable battery.
(7) Fill fuel tank. Use the DRB IIItscan tool to
pressurize the fuel system. Check for leaks.
(8) Install fuel filler cap.
FUEL RAIL
REMOVAL
REMOVAL - 2.4L
(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) Disconnect the wiring connectors for fuel injec-
tors harness (Fig. 12).
(4) Remove wiring harness from brackets.
(5) Disconnect the connectors from the fuel injec-
tors.
Fig. 10 FUEL PUMP MODULE LOCKING RING
Fig. 11 Fuel Pump Module Removal
1 - FUEL PUMP MODULE
2 - O-RING
Fig. 12 FUEL RAIL AND INJECTORS 2.4L
1 - Fuel Injectors
2 - Fuel Rail
RSFUEL DELIVERY14-9
FUEL PUMP MODULE (Continued)

(6) Remove harness from vehicle.
(7) Remove fuel hose quick connect fitting from the
chassis tube.Refer to Fuel Hoses, Clamps and
Quick Connect Fittings in this Section.Place a
shop towel under the connections to absorb any fuel
spilled from the fitting.
WARNING: WRAP A SHOP TOWEL AROUND HOSES
TO CATCH ANY GASOLINE SPILLAGE.
(8) Remove fuel rail attaching bolts.
(9) Remove fuel rail. Be careful not to damage the
injector O-rings upon removal from their ports.
REMOVAL - 3.3/3.8L
(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 upper intake manifold, refer to the
Engine/Manifolds/Upper Intake for more informa-
tion..
(4) Cover intake manifold with suitable cover
when servicing.
(5) Remove the fuel hose quick connect fitting from
the chassis tube.Refer to Fuel Hoses, Clamps
and Quick Connect Fittings in this Section.
WARNING: WRAP A SHOP TOWEL AROUND HOSES
TO CATCH ANY GASOLINE SPILLAGE.
(6) Remove the fuel rail attaching bolts (Fig. 13).
(7) Remove fuel rail. Be careful not to damage the
injector O-rings upon removal from their ports.
INSTALLATION
INSTALLATION - 2.4L
(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) Connect the connectors to the fuel injectors.
(6) Install wiring harness to brackets.
(7) Connect the wiring connectors to fuel injectors
harness (Fig. 12).
(8) Connect negative battery cable.
(9) Use the DRBIIItscan tool to pressurize the
fuel system. Check for leaks.
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.
Fig. 13 FUEL INJECTORS 3.3/3.8L
14 - 10 FUEL DELIVERYRS
FUEL RAIL (Continued)

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 (prior
to 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
(1) Remove fuel filler cap and perform Fuel Sys-
tem Pressure Release procedure (Fig. 14).
(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. 15).
(9) Disconnect the fuel fill hose at the fuel tank
filler metal tubeNOT AT THE FUEL TANK(Fig.
15).
(10) Disconnect fuel line and vapor line at the
front of the fuel tank.
The fuel pump module electrical connector
has a retainer that locks it in place.(11) Slide fuel pump module electrical connector
lock to unlock.
(12) Push down on connector retainer (Fig. 16) and
pull connector off module.
(13) Lower tank from vehicle. Remove fuel filler
vent tube from frame (Fig. 17).
Fig. 14 Fuel Tank
1 - ROLLOVER VALVE
2 - FUEL FILLER INLET
3 - ROLLOVER VALVE
4 - FUEL PUMP MODULE
Fig. 15 FUEL FILLER AND VENT TUBE
1 - Filler Tube
2 - Vent Tube
RSFUEL DELIVERY14-11
FUEL TANK (Continued)

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.
FUEL TANK FILLER TUBE
REMOVAL
(1) Disconnect the negative battery cable.
(2) Remove the 3 screws at the filler door.
(3) Raise and support vehicle
(4) Remove the left rear tire.
(5) Remove the splash shield (Fig. 19) or (Fig. 18).
(6)For RGRemove the canister from filler tube
(Fig. 20).
(7)For RGDisconnect the vent at the top of the
filler tube.
(8) Remove the ground strap.
(9) Remove filler tube at tank.
Fig. 16 Pump Module Connector Retainer and Lock
1 - PUSH DOWN ON RETAINER
2 - CONNECTOR LOCK
Fig. 17 VENT HOSE
Fig. 18 FUEL FILLER TUBE (RS)
14 - 12 FUEL DELIVERYRS
FUEL TANK (Continued)

INSTALLATION
(1) Install filler tube to tank (Fig. 19).
(2) Install the ground strap.
(3)For RGConnect the vent at the top of the filler
tube.
(4) Install the 3 screws at the filler door.(5)For RGInstall the canister from filler tube
(Fig. 20).
(6) Install the splash shield.
(7) Install the left rear tire.
(8) lower vehicle.
(9) Connect the negative battery cable.
INLET FILTER
REMOVAL
(1) Remove fuel pump module. Refer to Fuel Pump
Module Removal in this section.
(2) Using a thin straight blade screwdriver, pry
back the locking tabs on fuel pump reservoir and
remove the strainer (Fig. 21).
(3) Remove strainer O-ring from the fuel pump
reservoir body.
(4) Remove any contaminants in the fuel tank by
washing the inside of the fuel tank.
INSTALLATION
(1) Lubricate the strainer O-ring with clean engine
oil.
(2) Insert strainer O-ring into outlet of strainer so
that it sits evenly on the step inside the outlet.
(3) Push strainer onto the inlet of the fuel pump
reservoir body. Make sure the locking tabs on the
reservoir body lock over the locking tangs on the
strainer.
(4) Install fuel pump module. Refer to Fuel Pump
Module Installation in this section.
Fig. 19 FUEL FILLER TUBE AND VENT TUBE (RG)
Fig. 20 FUEL TUBE VENT CANISTER (RG)
Fig. 21 Inlet
1 - TABS
2 - INLET STRAINER
RSFUEL DELIVERY14-13
FUEL TANK FILLER TUBE (Continued)

QUICK CONNECT FITTING
STANDARD PROCEDURE - QUICK-CONNECT
FITTINGS
REMOVAL
When disconnecting a quick-connect fitting, the
retainer will remain on the fuel tube nipple.
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING A QUICK-CONNECT FIT-
TINGS. REFER TO THE FUEL PRESSURE RELEASE
PROCEDURE. THIS MAY RESULT IN PERSONAL
INJURY OR DEATH.
(1) Perform Fuel Pressure Release Procedure.
Refer to the Fuel Pressure Release Procedure in this
section.
(2) Disconnect negative cable from battery or aux-
iliary jumper terminal.
(3) Squeeze retainer tabs together and pull fuel
tube/quick-connect fitting assembly off of fuel tube
nipple. The retainer will remain on fuel tube.
INSTALLATION
CAUTION: Make sure that the o-ring in installed in
fitting. Never install a quick-connect fitting without
the retainer being either on the fuel tube or already
in the quick-connect fitting. In either case, ensure
the retainer locks securely into the quick-connect
fitting by firmly push-pulling-push on fuel tube and
fitting to ensure it is secured.
(1) Using a clean lint free cloth, clean the fuel tube
nipple and retainer.
(2) Prior to connecting the fitting to the fuel tube,
coat the fuel tube nipple with clean engine oil.
(3) Push the quick-connect fitting over the fuel
tube until theretainer seats and a click is heard.
(4) The plastic quick-connect fitting has windows
in the sides of the casing. When the fitting com-
pletely attaches to the fuel tube, the retainer locking
ears and the fuel tube shoulder are visible in the
windows. If they are not visible, the retainer was not
properly installed (Fig. 22).Do not rely upon the
audible click to confirm a secure connection.
(5) Connect negative cable to battery or auxiliary
jumper terminal.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for several minutes, until the test is stopped, or
until the ignition switch is turned to the Off posi-
tion.(6) Use the DRB IIItscan tool ASD Fuel System
Test to pressurize the fuel system. Check for leaks.
TWO-TAB TYPE FITTING
This type of fitting is equipped with tabs located on
both sides of the fitting (Fig. 23). These tabs are sup-
plied for disconnecting the quick-connect fitting from
component being serviced.
CAUTION: The interior components (O-rings, spac-
ers) of this type of quick-connect fitting are not ser-
viced separately, but new plastic retainers are
available. Do not attempt to repair damaged fittings
or fuel lines/tubes. If repair is necessary, replace
the complete fuel tube assembly.
Fig. 22 Plastic Quick-Connect Fitting/Fuel Tube
Connection
1 - WINDOW
2-TAB(2)
3 - EAR
4 - SHOULDER (ON TUBE)
Fig. 23 Typical Two-Tab Type Quick-Connect Fitting
1 - TAB(S)
2 - QUICK-CONNECT FITTING
14 - 14 FUEL DELIVERYRS

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
PRESSURE RELEASE PROCEDURE IN THIS
GROUP. THIS MAY RESULT IN PERSONAL INJURY
OR DEATH.
DISCONNECTION/CONNECTION
(1) Perform fuel pressure release procedure. Refer
to Fuel Pressure Release Procedure in this group.
(2) Disconnect negative battery cable from battery
or auxiliary jumper terminal.
(3) Clean fitting of any foreign material before dis-
assembly.
(4) To disconnect quick-connect fitting, squeeze
plastic retainer tabs (Fig. 23) against sides of quick-
connect fitting with your fingers. Tool use is not
required for removal and may damage plastic
retainer. Pull fitting from fuel system component
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
component 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 dam-
age.
(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 push-pull-
ing-push on fuel tube and fitting (15-30 lbs.).
(9) Connect negative cable to battery or auxiliary
jumper terminal.
(10) Use the DRB IIItscan tool ASD Fuel System
Test to pressurize the fuel system. 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. 24) 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. THIS MAY RESULT IN PERSONAL
INJURY OR DEATH.
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
Fig. 24 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
RSFUEL DELIVERY14-15
QUICK CONNECT FITTING (Continued)

retainer ring into fitting (Fig. 24). 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 push-pull-
ing-push on fuel tube and fitting (15-30 lbs.).
(10) Connect negative battery cable to battery or
auxiliary jumper terminal.
(11) Use the DRB IIItscan tool ASD Fuel System
Test to pressurize the fuel system. Check for leaks.
14 - 16 FUEL DELIVERYRS
QUICK CONNECT FITTING (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 INJECTION14-19
FUEL INJECTION (Continued)