speed sensor CHRYSLER VOYAGER 2002 Owners Manual

INSPECTION
Check manifold for:
²Damage and cracks.
²Mounting surface distortion by using a straight-
edge and thickness gauge.
INSTALLATION - UPPER INTAKE MANIFOLD
(1) If the following components were removed from
manifold, install and tighten to specifications:
CAUTION: The special screws used for the compos-
ite manifold attached components must be installed
slowly using hand tools only. This requirement is to
prevent the melting of material that causes stripped
threads. If threads become stripped, an oversize
repair screw is available. For more information and
procedure (Refer to 9 - ENGINE/MANIFOLDS/IN-
TAKE MANIFOLD - STANDARD PROCEDURE - MAN-
IFOLD STRIPPED THREAD REPAIR).²MAP sensor - 1.7 N´m (15 in. lbs.)
²Throttle cable bracket - 5.6 N´m (50 in. lbs.)
(2) Remove covering on lower intake manifold and
clean surfaces.
(3) Inspect manifold gasket condition. Gaskets can
be re-used, if not damaged. To replace, remove gasket
from upper manifold (Fig. 123). Position new gasket
in seal channel and press lightly in-place. Repeat
procedure for each gasket position.
(4) Position upper manifold on lower manifold (Fig.
123). Install and tighten bolts to 12 N´m (105 in. lbs.)
following torque sequence in (Fig. 124).
(5) Connect the MAP sensor electrical connector.
(6) Connect the brake booster and LDP vacuum
hose to intake manifold (Fig. 122).
CAUTION: The special screws used for attaching
the EGR tube and power steering reservoir to the
manifold must be installed slowly using hand tools
only. This requirement is to prevent the melting of
material that causes stripped threads. If threads
become stripped, an oversize repair screw is avail-
able. For more information and procedure (Refer to
9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD - STAN-
DARD PROCEDURE - MANIFOLD STRIPPED
THREAD REPAIR).
(7) Install the power steering reservoir (Fig. 121).
Tighten screws to manifold to 5.6 N´m (50 in. lbs.).
(8) Connect throttle and speed control cables to
throttle body (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/THROTTLE CONTROL CABLE -
INSTALLATION)
(9) Attach make up air hose clip into the hole in
the throttle cable bracket.
(10) Connect the wiring connectors to the throttle
position sensor (TPS) and Automatic Idle Speed (AIS)
motor.
Fig. 123 INTAKE MANIFOLD - UPPER
1 - BOLT
2 - MAP SENSOR
3 - SCREW
4 - MANIFOLD - UPPER
5 - WIRE HARNESS
6 - GASKET (3 PER CYL. BANK)
Fig. 124 UPPER MANIFOLD TIGHTENING
SEQUENCE
RSENGINE 3.3/3.8L9 - 149
INTAKE MANIFOLD - UPPER (Continued)
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(17) Remove battery shield.
(18) Remove charge air cooler outlet hose.
(19) Remove charge air cooler inlet hose (Fig. 6).
(20) Disconnect upper radiator hose at engine (Fig.
7).
(21) Disconnect lower radiator hose at engine (Fig.
7).
(22) Disconnet brake booster vacuum supply hose.
(23) Disconnect heater core return hose at engine.
(24) Disconnect egr solenoid vacuum line at brake
booster check valve.
(25) Disconnect fuel injector, cam sensor, boost
pressure/intake air temp sensor, fuel rail high pres-
sure, and egr solenoid connectors (Fig. 8).
(26) Disconnect generator electrical connectors.
(27) Disconnect coolant temp sensor and glow plug
electrical connectors.
(28) Disconnect injection pump and A/C compres-
sor electrical connectors.
(29) Disconnect starter electrical connectors.
(30) Disconnect ground wires at engine block.
(31) Raise vehicle on hoist.
(32) Disconnect oil temp sensor, oil pressure sen-
sor, engine speed sensor, and vehicle speed sensor
electrical connector (Fig. 9).(33) Remove front wheels.
(34) Remove the suspension cradle assembly (Refer
to 13 - FRAME & BUMPERS/FRAME/ENGINE
CRADLE CROSSMEMBER - REMOVAL).
(35) Remove both axle shaft assemblies (Refer to 3
- DIFFERENTIAL & DRIVELINE/HALF SHAFT -
REMOVAL).
(36) Disconnect the clutch slave cylinder quick dis-
connect line (RHD only)(Refer to 6 - CLUTCH/SLAVE
CYLINDER - REMOVAL).
(37) Disconnect reverse lamp connector.
(38) Disconnect shifter cables at the tranmission
(Refer to 21 - TRANSMISSION/TRANSAXLE/MAN-
UAL/GEAR SHIFT CABLE - REMOVAL).
(39) Disconnect exhaust pipe from the turbo-
charger downpipe and reposition to right side of vehi-
cle.
(40) Disconnect cabin heater coolant line (Refer to
24 - HEATING & AIR CONDITIONING/CABIN
HEATER/HEATER UNIT - REMOVAL).
(41) Remove front engine mount bracket retaining
bolts from lower radiator support
(42) Lower vehicle. Evacuate the A/C system
(Refer to 24 - HEATING & AIR CONDITIONING/
Fig. 6 CHARGE AIR COOLER HOSES
1 - COOLING MODULE
2 - BYPASS HOSE
3 - UPPER RADIATOR HOSE
4 - CHARGE AIR COOLER OULET HOSE
5 - CHARGE AIR COOLER INLET HOSE
6 - LOWER RADIATOR HOSE
7 - CHARGE AIR COOLER
Fig. 7 UPPER AND LOWER RADIATOR HOSES
1 - COOLANT BYPASS HOSE
2 - RADIATOR ASSEMBLY
3 - UPPER RADIATOR HOSE
4 - COOLING FAN
5 - LOWER RADIATOR HOSE
6 - CHARGE AIR COOLER
7 - RADIATOR BRACKET
RGENGINE9a-5
ENGINE 2.5L TURBO DIESEL (Continued)
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PLUMBING/REFRIGERANT - STANDARD PROCE-
DURE).
(43) Disconnect the A/C lines at the A/C compres-
sor.
(44) Disconnect the fuel supply and return lines.
(45) Position engine cradle under engine and lower
vehicle over cradle.
(46) Remove right engine mount bolts.
(47) Remove left engine mount through bolt.
(48) Raise vehicle, leaving engine and transmis-
sion on engine cradle.
(49) Lift engine from engine cradle and diassemble
as necessary.
REMOVAL - ENGINE COVER
(1) Remove engine cover retaining bolts.
(2) Remove engine cover from engine (Fig. 10).
Fig. 8 ENGINE COMPONENT LOCATIONS
1 - FUEL INJECTOR RETURN LINE
2 - FUEL INJECTOR SUPPLY LINE
3 - OIL SEPARATOR
4 - FUEL INJECTOR
5 - CAMSHAFT POSITION SENSOR
6 - BOOST PRESSURE/INTAKE AIR TEMPERATURE SENSOR
7 - EGR SOLENOID
8 - FUEL PRESSURE SENSOR
9 - CYLINDER HEAD COVER/INTAKE MANIFOL
10 - FUEL RAIL
11 - WIRING HARNESS RETAINING CLIPS
Fig. 9 REAR ENGINE VIEW
1 - SUSPENSION CRADLE
2 - ENGINE BLOCK
3 - OIL PRESSURE SWITCH
4 - OIL TEMPERATURE SENSOR
5 - VEHICLE SPEED SENSOR
6 - TRANSMISSION
Fig. 10 ENGINE COVER
1 - ENGINE COVER MOUNTING BOLTS
2 - ENGINE COVER
9a - 6 ENGINERG
ENGINE 2.5L TURBO DIESEL (Continued)
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INSTALLATION
INSTALLATION - 2.5L TURBO DIESEL ENGINE
(1) Reassembly engine and transmission assembly
and install on engine cradle.
(2) Position engine and cradle assembly under
vehicle.
(3) Slowly lower the vehicle down over the engine
and cradle assembly.
(4) Install right engine mount bolts. Torque to
54N´m (40 ft. lbs.)
(5) Install left engine mount through bolt. Torque
to 75N´m (55 ft. lbs.)
(6) Raise vehicle and engine from engine cradle.
(7) Attach front engine mount bracket to lower
radiator support. Torque to 54N´m (40 ft. lbs.)
(8) Connect cabin heater coolant hose.
(9) Connect exhaust pipe to the turbocharger
downpipe flange. Torque to 28 N´m (250 in. lbs.)
(10) Connect reverse lamp electrical connector at
transmission.
(11) Connect both shifter cables (Refer to 21 -
TRANSMISSION/TRANSAXLE/MANUAL/GEAR
SHIFT CABLE - INSTALLATION).
(12) Connect the clutch slave cylinder quick dis-
connect connector (RHD only)(Refer to 6 - CLUTCH/
SLAVE CYLINDER - INSTALLATION).
(13) Install engine harness into bracket on trans-
mission.
(14) Lower vehicle.
(15) Connect fuel supply and return lines.
(16) Connect A/C lines to A/C compressor. Torque
to 23N´m (17 ft. lbs.)
(17) Route engine wiring harnes to proper location.
(18) Connect engine harness ground cables to
engine block
(19) Connect starter solenoid electrical connector
and battery feed wire to starter. Torque to 10N´m (90
in. lbs.)
(20) Connect A/C compressor, injection pump, glow
plugs, and coolant temperature sensor electrical con-
nectors.
(21) Connect generator electrical connector. Torque
to 9N´m (75 in. lbs.)
(22) Connect the fuel injector, fuel pressure sensor,
boost pressure/intake air temp sensor, cam sensor,
and egr solenoid electrical connectors (Fig. 8).
(23) Connect egr solenoid vacuum supply line to
brake boost vacuum supply line.(24) Connect brake booster vacuum supply line.
(25) Connect heater core return hose to coolant
pipe.
(26) Connect lower radiator hose to engine (Fig. 7).
(27) Install charger air cooler inlet hose (Fig. 6).
(28) Install charge air cooler outlet hose (Fig. 6).
(29) Connect upper radiator hose to engine (Fig.
7).
(30) Install battery shield.
(31) Install coolant reserve pressure container
(Refer to 7 - COOLING/ENGINE/COOLANT RECOV-
ERY PRESS CONTAINER - INSTALLATION).
(32) Install power steering reservoir and bracket
(Fig. 4).
(33) Raise vehicle
(34) Connect oil pressure sensor, oil temperature
sensor, engine speed sensor, and vehicle speed sensor
electrical connector (Fig. 9).
(35) Install suspension cradle in vehicle (Refer to
13 - FRAME & BUMPERS/FRAME/ENGINE CRA-
DLE CROSSMEMBER - INSTALLATION).
(36) Install both axle shaft assemblies (Refer to 3 -
DIFFERENTIAL & DRIVELINE/HALF SHAFT -
INSTALLATION).
(37) Connect the power steering supply, pressure,
and return lines to power steering pump (Fig. 4).
(38) Install the power steering line brackets on oil
pan (Fig. 4).
(39) Install lower splash shield and side panels.
(40) Install both front wheel and tire assemblies.
(41) Lower vehicle.
(42) Install air cleaner housing, MAF sensor, and
air intake tube assembly (Fig. 3).
(43) Refill transmission to proper level (Refer to 21
- TRANSMISSION/TRANSAXLE/MANUAL/FLUID -
STANDARD PROCEDURE).
(44) Refill engine coolant (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(45) Recharge A/C system (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/REFRIGER-
ANT - STANDARD PROCEDURE) .
(46) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION) (Fig. 2).
(47) Connect negative battery cable.
INSTALLATION - ENGINE COVER
(1) Install engine cover on engine.
(2) Install the engine cover mounting bolts (Fig.
10).
RGENGINE9a-7
ENGINE 2.5L TURBO DIESEL (Continued)
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(3) Install oil pump retaining bolts (Fig. 71).
Torque bolts to 10.8N´m.
(4) Install crankshaft sprocket (Fig. 71). Torque
bolts to 10.8N´m.
(5) Install front engine cover (Refer to 9 -
ENGINE/ENGINE BLOCK/ENGINE COVER -
INSTALLATION).
(6) Install timing belt inner cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(7) Install timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION) .
(8) Install timing belt outer cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(9) Install accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(10) Install power steering belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(11) Connect negative battery cable.
INSTALLATION
(1) Lubricate o-ring on oil pump pickup tube with
engine oil.
(2) Install pickup tube in engine block and install
retaining bolt (Fig. 72). Torque bolt to 32.4N´m.
(3) Install oil pan (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PAN - INSTALLATION).
(4) Refill engine oil to proper level.
(5) Connect negative battery cable.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The oil pressure switch is located on the right side
of the engine block. The switch screws into the
engines main oil gallery (Fig. 73).
REMOVAL
(1) Disconnect negative battery cable.
(2) Raise vehicle on hoist.
(3) Disconnect oil pressure switch electrical con-
nector (Fig. 73).
(4) Remove oil pressure switch from engine block.
INSTALLATION
(1) Apply MopartThread Sealant to the switch
threads.
(2) Install oil pressure switch in engine block.
(3) Connect oil pressure switch electrical connector
(Fig. 73).(4) Lower vehicle.
(5) Start engine and check for leaks.
(6) Check and adjust oil level as necessary.
OIL TEMPERATURE SENSOR
DESCRIPTION
The oil temperature sensor is located on the right
side of the engine block. The sensor screws into the
engines main oil gallery (Fig. 74).
REMOVAL
(1) Disconnect negative battery cable.
(2) Raise vehicle on hoist.
(3) Disconnect oil temperature sensor electrical
connector (Fig. 74).
(4) Remove oil temperature sensor from engine
block.
INSTALLATION
(1) Apply MopartThread Sealant to the sensor
threads.
(2) Install oil temperature sensor in engine block.
(3) Connect oil temperature sensor electrical con-
nector (Fig. 74)
Fig. 73 REAR ENGINE VIEW
1 - SUSPENSION CRADLE
2 - ENGINE BLOCK
3 - OIL PRESSURE SWITCH
4 - OIL TEMPERATURE SENSOR
5 - VEHICLE SPEED SENSOR
6 - TRANSMISSION
9a - 48 ENGINERG
OIL PUMP (Continued)
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(4) Lower vehicle.
(5) Start engine and check for leaks.
(6) Check and adjust oil level as necessary.
OIL PRESSURE RELIEF VALVE
DESCRIPTION
The oil pressure relief valve mounts in the front of
the engine block and is used to control oil flow
through the engines lubrication system (Fig. 75).
REMOVAL
(1) Remove engine oil pan (Refer to 9 - ENGINE/
LUBRICATION/OIL PAN - REMOVAL).
(2) Using special tool VM.1054, remove oil pres-
sure relief valve from engine block (Fig. 76).
INSTALLATION
(1) Thoroughly clean all components and relief
valve pocket in cylinder block.
(2) Lubricate all oil pressure relief valve compo-
nents with engine oil.
(3) Install oil pressure relief valve plunger, spring,
and cap.
Fig. 74 REAR ENGINE VIEW
1 - SUSPENSION CRADLE
2 - ENGINE BLOCK
3 - OIL PRESSURE SWITCH
4 - OIL TEMPERATURE SENSOR
5 - VEHICLE SPEED SENSOR
6 - TRANSMISSION
Fig. 75 OIL PRESSURE RELIEF VALVE
1 - O-RING
2 - OIL PRESSURE RELIEF VALVE CAP
3 - OIL PRESSURE RELIEF VALVE SPRING
4 - OIL PRESSURE RELIEF VALVE PLUNGER
Fig. 76 OIL PRESSURE RELIEF VALVE REMOVAL
1 - VM.1054
2 - OIL PRESSURE RELIEF VALVE
3 - ENGINE BLOCK
4 - OIL PUMP
RGENGINE9a-49
OIL TEMPERATURE SENSOR (Continued)
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(1) Disconnect and remove the upstream (before
catalytic converter) oxygen sensor. (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/O2 SENSOR -
REMOVAL)
(2) Install the Exhaust Back Pressure Fitting
Adaptor CH8519.
(3) Connect the Low Pressure Sensor (15 psi)
CH7063 to the back pressure fitting.
(4) Following the PEP module instruction manual,
connect all required cables to the DRB IIItand PEP
module. Select the available menu options on the
DRBIIItdisplay screen for using the digital pressure
gauge function.
(5) Apply the park brake and start the engine.
(6) With transmission in Park or Neutral, raise
engine speed to 2000 RPM. Monitor the pressure
readings on the DRBIIIt. Back pressure should not
exceed specified limit. Refer to specification in table
below EXHAUST BACK PRESSURE LIMITS .
NOTE: For applications with dual catalytic convert-
ers, repeat test on opposite converter using the
previous steps.
(7) If pressure exceeds maximum limits, inspect
exhaust system for restricted component. For further
catalytic converter inspection procedures, (Refer to 11
- EXHAUST SYSTEM/CATALYTIC CONVERTER -
INSPECTION). Replace component(s) as necessary.
EXHAUST BACK PRESSURE LIMITS
Exhaust Back Pressure Limit (Max)
Vehicle in Park/Neutral
(no load) RPM3.45 Kpa (0.5 psi)
INSPECTION
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
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, damaged or loose compo-
nents such as; clamps, heat shields, isolators, andhanger 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:
(1) Loosen band clamp at catalytic converter pipe
to muffler/resonator assembly.
(2) Align the exhaust system by inserting pipe
inward or outward until specification is achieved as
shown in (Fig. 2).
(3) Tighten band clamp to 54 N´m (40 ft. lbs.).
SPECIFICATIONS
TORQUE
DESCRIPTION N´mFt.
Lbs.In.
Lbs.
Band Clamp 54 40 Ð
Cross-over PipeÐFastener 41 30 Ð
Exhaust Manifold FlangeÐFastener 37 Ð 325
Heat Shield (Muffler)ÐFastener 2.6 Ð 23
Heat Shield (Toe Board)ÐFastener 2.6 Ð 23
Heat Shield (Resonator Pipe)Ð
Fastener2.6 Ð 23
Insulator Mounting BracketÐBolts 28 Ð 250
Fig. 2 Exhaust System Alignment
1 - HANGER BRACKET TO BODY
2 - ISOLATOR
3 - HANGER - MUFFLER/RESONATOR SUPPORT
4-6mm(0.25 in.)
RSEXHAUST SYSTEM11-3
EXHAUST SYSTEM (Continued)
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FUEL INJECTION
TABLE OF CONTENTS
page page
FUEL INJECTION
OPERATION
OPERATION - INJECTION SYSTEM.......17
OPERATION - MODES OF OPERATION....17
FUEL CORRECTION or ADAPTIVE
MEMORIES..........................19
PROGRAMMABLE COMMUNICATIONS
INTERFACE (PCI) BUS.................20
SYSTEM DIAGNOSIS..................21
SPECIFICATIONS
TORQUE............................21
SPECIAL TOOLS
FUEL...............................22
ACCELERATOR PEDAL
REMOVAL.............................22
INSTALLATION.........................23
CRANKSHAFT POSITION SENSOR
DESCRIPTION.........................23
OPERATION...........................24
REMOVAL.............................24
INSTALLATION - 2.4L....................24
ENGINE SPEED SENSOR
DESCRIPTION.........................24
OPERATION...........................25
FUEL INJECTOR
DESCRIPTION.........................25
OPERATION...........................25
REMOVAL
REMOVAL - 2.4L......................25
REMOVAL - 3.3/3.8L...................26
INSTALLATION
INSTALLATION - 2.4L..................26
INSTALLATION - 3.3/3.8L................26
FUEL PUMP RELAY
DESCRIPTION.........................27
OPERATION...........................27
IDLE AIR CONTROL MOTOR
DESCRIPTION.........................27
OPERATION...........................27
REMOVAL.............................28INSTALLATION.........................28
INLET AIR TEMPERATURE SENSOR
DESCRIPTION.........................28
OPERATION...........................28
MAP SENSOR
DESCRIPTION.........................29
OPERATION...........................29
REMOVAL
REMOVAL - 2.4L......................30
REMOVAL - 3.3/3.8L...................30
INSTALLATION
INSTALLATION - 2.4L..................30
INSTALLATION - 3.3/3.8L................30
O2 SENSOR
DESCRIPTION.........................30
OPERATION...........................31
REMOVAL
REMOVAL - UPSTREAM 1/1 - 2.4L........32
REMOVAL - UPSTREAM 1/1 - 3.3/3.8L.....32
REMOVAL - DOWNSTREAM 1/2 - 2.4/3.3/
3.8L................................32
INSTALLATION
INSTALLATION - UPSTREAM 1/1 - 2.4L.....32
INSTALLATION - UPSTREAM 1/1 - 3.3/3.8L . . 33
INSTALLATION DOWNSTREAM 2/1 -
2.4/3.3/3.8L..........................33
THROTTLE BODY
DESCRIPTION.........................33
OPERATION...........................33
REMOVAL.............................34
INSTALLATION.........................34
THROTTLE CONTROL CABLE
REMOVAL.............................34
INSTALLATION.........................34
THROTTLE POSITION SENSOR
DESCRIPTION.........................35
OPERATION...........................35
REMOVAL - 3.3/3.8L.....................35
INSTALLATION - 3.3/3.8L.................35
14 - 16 FUEL INJECTIONRS
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FUEL INJECTION
OPERATION
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.
The PCM can adapt its programming to meet
changing 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 theprimaryinputs that determine
injector pulse width.
OPERATION - MODES OF 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 35ÉF the PCM will wait 38
seconds.
²If the coolant is over 50ÉF the PCM will wait 15
seconds.
²If the coolant is over 167ÉF the PCM will wait 3
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 0.29 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
RSFUEL INJECTION14-17
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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, (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 position²Knock sensor
²Throttle position
²A/C switch
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
²A/C control positions
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.
²All monitored components (refer to the Emission
section for On-Board Diagnostics).
14 - 18 FUEL INJECTIONRS
FUEL INJECTION (Continued)
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