coolant temperature CHRYSLER VOYAGER 2001 Manual Online

INSTALLATION
(1) Place a bead (approximately 1/4 in. diameter)
of MopartEngine RTV GEN II onto each of thefour
manifold to cylinder head gasket corners (Fig. 138).
(2) Carefully install the new intake manifold gas-
ket (Fig. 139). Tighten end seal retainer screws to 12
N´m (105 in. lbs.).
(3) Install lower intake manifold (Fig. 139). Install
the bolts and torque to 1 N´m (10 in. lbs.). Then
torque bolts to 22 N´m (200 in. lbs.) in sequence
shown in (Fig. 140). Then torque again to 22 N´m
(200 in. lbs.). After intake manifold is in place,
inspect to make sure seals are in place.
(4) Install the fuel injectors and rail assembly.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
FUEL RAIL - INSTALLATION)
(5) Connect fuel injector electrical harness.
(6) Connect the engine coolant temperature sensor
(Fig. 136).
(7) Connect the heater supply (Fig. 136) and radi-
ator upper hoses to manifold.
(8) Connect the fuel line. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE)
(9) Install the upper intake manifold. (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION)
(10) Connect negative battery cable.(11) Fill the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
Fig. 136 ECT SENSOR & HEATER SUPPLY
1 - ENGINE COOLANT TEMPERATURE SENSOR
2 - CONNECTOR - ENGINE COOLANT SENSOR
3 - FITTING - HEATER SUPPLY
Fig. 137 INTAKE MANIFOLD - LOWER
1 - INTAKE MANIFOLD - LOWER
2 - BOLT - GASKET END SEAL RETAINER
3 - GASKET
4 - BOLT - LOWER INTAKE MANIFOLD
Fig. 138 Intake Manifold Gasket Sealing
1 - SEALER LOCATIONS
RSENGINE 3.3/3.8L9 - 149
INTAKE MANIFOLD - LOWER (Continued)

(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. 9).
(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. 8).
(27) Install charger air cooler inlet hose (Fig. 7).
(28) Install charge air cooler outlet hose (Fig. 7).
(29) Connect upper radiator hose to engine (Fig.
8).
(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. 5).
(33) Raise vehicle
(34) Connect oil pressure sensor, oil temperature
sensor, engine speed sensor, and vehicle speed sensor
electrical connector (Fig. 10).(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. 5).
(38) Install the power steering line brackets on oil
pan (Fig. 5).
(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. 4).
(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. 3).
(47) Connect negative battery cable.
INSTALLATION - ENGINE COVER
(1) Install engine cover on engine.
(2) Install the engine cover mounting bolts (Fig.
11).
SPECIFICATIONS
SPECIFICATIONS - 2.5L COMMON RAIL
DIESEL ENGINE
ENGINE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Type R2516C
Number of Cylinders 4
Bore 92 mm
Stroke 94 mm
Displacement 2499.5cc
Injection Order 1-3-4-2
Compression Ratio 17.5:1 (  0.5)
Maximum Power 103kW (140 HP) @ 4000
RPM
Peak Torque 340Nm (34.6 kgm) @
1800 RPM
RGENGINE 2.5L TURBO DIESEL9a-7
ENGINE 2.5L TURBO DIESEL (Continued)

INSPECTION
Use a straightedge and feeler gauge to check the
flatness of the engine cylinder head and block mating
surfaces.
The minimum cylinder head thickness is 89.95mm
(3.541 in.).
INSTALLATION
CAUTION: Piston protrusion must be measured to
determine cylinder head gasket thickness if one or
more cylinder liners have benn replaced (Refer to 9
- ENGINE/CYLINDER HEAD - STANDARD PROCE-
DURE).
NOTE: If cylinder liner(s) have not been removed,
the same thickness head gasket that was removed
can be used.(1) Clean and inspect gasket mating surfaces.
(2) Position correct head gasket on engine block.
(3) Place cylinder head on engine block (Fig. 19).
CAUTION: New cylinder head bolts must be uesd.
(4) Tighten cylinder head bolts following procedure
below.
Cylinder Head Bolt Torquing Procedure
(1) Lubricate cylinder head bolts with engine oil.
(2) Torque bolts to 30N´m in numerical starting
with bolt #1 (Fig. 20).
(3) Tighten all bolts an additional 50É, starting
with bolt #4 then 5-6-7-8-9-10-1-2-3-11-12-13-14-15-
16-17-18 (Fig. 20).
(4) Finally tighten all bolts an additional 75É in
numerical order starting with bolt #1 (Fig. 20).
(5) Slide exhaust manifold and turbocharger on
exhaust manifold studs (Fig. 18).
(6) Install exhaust manifold retaining nuts. Torque
nuts to 32.4N´m.
(7) Install exhaust manifold heat shield (Fig. 18).
Torque bolts to 27.5N´m.
(8) Install turbocharger outlet to charge air cooler
pipe (Fig. 17).
(9) Install thermostat housing to upper radiator
hose pipe (Fig. 17). Install retaining bolt and torque
to 47.1N´m.
(10) Install coolant recovery pressure container
(Refer to 7 - COOLING/ENGINE/COOLANT RECOV-
ERY PRESS CONTAINER - INSTALLATION).
Fig. 19 CYLINDER HEAD ASSEMBLY
1 - VALVE SPRING
2 - CYLINDER HEAD BOLT
3 - GLOW PLUG
4 - COOLANT TEMPERATURE SENSOR
5 - CYLINDER HEAD ALIGNMENT DOWEL
6 - CYLINDER BLOCK
7 - CYLINDER LINER
8 - ENGINE BLOCK DECK
9 - CYLINDER HEAD GASKET
10 - CYLINDER HEAD
11 - ROCKER ARM AND LIFTER ASSEMBLY
Fig. 20 CYLINDER HEAD TORQUE SEQUENCE
9a - 22 ENGINE 2.5L TURBO DIESELRG
CYLINDER HEAD (Continued)

(11) Connect glow plug and coolant temperature
sensor electrical connectors.
(12) Install new cylinder head cover/intake mani-
fold gasket.
(13) Install rocker arm and lifter assemblies.Be
sure to put rocker arm and lifter assemblies in
same location as removed.
(14) Install cylinder head cover/intake manifold
(Fig. 16)(Refer to 9 - ENGINE/CYLINDER HEAD/
CYLINDER HEAD COVER(S) - INSTALLATION).
(15) Install timing belt inner cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(16) Install timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION) .
(17) Install timing belt outer cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(18)Remove crankshaft and both camshaft
locking pins at this time(Refer to 9 - ENGINE/
VALVE TIMING - STANDARD PROCEDURE).
(19) Install generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - INSTALLATION).
(20) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(21) Install power steering belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(22) Install right engine mount (Refer to 9 -
ENGINE/ENGINE MOUNTING/RIGHT MOUNT -
INSTALLATION).
(23) Install air cleaner housing assembly.
(24) Refill cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(25) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
(26) Install front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(27) Connect negative battery cable.
CAMSHAFT(S)
DESCRIPTION
The camshafts are made of gray cast iron with
eight machined lobes and four bearing journals (Fig.
21).
OPERATION
When the camshaft rotates the lobes actuate the
hydraulic lifters and rocker arms, forcing downward
on the rocker arms which opens the valves.
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL).
(3) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(4) Drain cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(5) Remove air cleaner housing.
(6) Remove power steering belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(7) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(8) Remove generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - REMOVAL).
(9) Support engine and remove right engine mount
(Refer to 9 - ENGINE/ENGINE MOUNTING/RIGHT
MOUNT - REMOVAL).
CAUTION: Before removing the cylinder head cover/
intake manifold or timing belt the engine must put
at 90É after TDC. Failure to do so could result in
valve and/or piston damage during reassembly.
(Refer to 9 - ENGINE/VALVE TIMING - STANDARD
PROCEDURE)
(10) Remove timing belt outer cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(11) Remove timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL).
(12) Remove timing belt inner cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
Fig. 21 CAMSHAFTS
1 - INTAKE CAMSHAFT
2 - EXHAUST CAMSHAFT
RGENGINE 2.5L TURBO DIESEL9a-23
CYLINDER HEAD (Continued)

(4) Install turbo inlet tube retaining bolt at intake
manifold. Torque bolt to 27.5 N´m.
(5) Connect oil separator outlet hose at separator.
(6) Install oil dipstick tube retaining bolt at intake
manifold inlet. Torque bolt to 10 N´m.
(7) Install power steering pump reservoir in
bracket.
(8) Install fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL RAIL - INSTALLATION).
(9) Install fuel injectors and fuel injector supply
lines (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION/FUEL INJECTOR - INSTALLATION).
(10) Connect vacuum lines at EGR solenoid.
(11) Clip wiring harness retainers on studs on fuel
rail (Fig. 24).
(12) Connect camshaft position sensor, boost pres-
sure/intake air temperature sensor, EGR solenoid,
and fuel pressure sensor electrical connectors (Fig.
24).
(13) Install inner timing belt cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(14) Install timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION) .
(15) Install outer timing belt cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(16) Install right engine mount (Refer to 9 -
ENGINE/ENGINE MOUNTING/RIGHT MOUNT -
INSTALLATION).
(17) Install generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - INSTALLATION).
(18) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(19) Install power steering belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(20) Install air cleaner housing assembly.
(21) Remove crankshaft and both camshaft locking
pins (Refer to 9 - ENGINE/VALVE TIMING - STAN-
DARD PROCEDURE).
(22) Refill cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(23) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
(24) Install front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(25) Connect negative battery cable.
Fig. 27 CYLINDER HEAD COVER/INTAKE
MANIFOLD ALIGNMENT STUDS VM.1066
1 - CYLINDER HEAD COVER/INTAKE MANIFOLD ALIGNMENT
STUDS VM.1066
2 - CYLINDER HEAD
Fig. 28 CYLINDER HEAD COVER/INTAKE
MANIFOLD TIGHTENING SEQUENCE
RGENGINE 2.5L TURBO DIESEL9a-27
CYLINDER HEAD COVER(S) (Continued)

INSTALLATION
(1) Clean and inspect gasket sealing surfaces.
(2) Install new gasket on cylinder head.
(3) Lubricate lifter ball end of lifter(s), valve(s),
and rocker arm roller(s) with MopartEngine Oil
Supplement or equivlalent.
(4) Connect rocker arm(s) to lifter and reposition
on valve(s) (Fig. 31).
(5) Install cylinder head cover/intake manifold
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - INSTALLATION).(6) Install inner timing belt 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 outer timing belt cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(9) Install right engine mount (Refer to 9 -
ENGINE/ENGINE MOUNTING/RIGHT MOUNT -
INSTALLATION).
(10) Install air cleaner housing assembly.
(11) Install front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(12) Connect negative battery cable.
Fig. 30 CYLINDER HEAD ASSEMBLY
1 - VALVE SPRING
2 - CYLINDER HEAD BOLT
3 - GLOW PLUG
4 - COOLANT TEMPERATURE SENSOR
5 - CYLINDER HEAD ALIGNMENT DOWEL
6 - CYLINDER BLOCK
7 - CYLINDER LINER
8 - ENGINE BLOCK DECK
9 - CYLINDER HEAD GASKET
10 - CYLINDER HEAD
11 - ROCKER ARM AND LIFTER ASSEMBLY
Fig. 31 ROCKER ARM ASSEMBLY
1 - ROCKER ARM ASSEMBLY
2 - CYLINDER HEAD COVER/INTAKE MANIFOLD
3 - HYDRAULIC LIFTER
4 - CYLINDER HEAD
5 - VALVE
RGENGINE 2.5L TURBO DIESEL9a-29
ROCKER ARMS (Continued)

HYDRAULIC LIFTERS
DESCRIPTION
Valve lash is controlled by hydraulic tappets
located inside the cylinder head, in tappet bores
below the camshafts (Fig. 32).
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL).
(3) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(4) Support engine and remove right engine mount
(Refer to 9 - ENGINE/ENGINE MOUNTING/RIGHT
MOUNT - REMOVAL).(5) Remove outer timing belt cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
CAUTION: Before removing the cylinder head cover/
intake manifold or the timing belt the engine must
put at 90É after TDC. Failure to do so could result in
valve and/or piston damage during reassembly.
(Refer to 9 - ENGINE/VALVE TIMING - STANDARD
PROCEDURE)
(6) Remove timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL).
(7) Remove inner timing belt cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(8) Remove cylinder head cover/intake manifold
(Fig. 33)(Refer to 9 - ENGINE/CYLINDER HEAD/
CYLINDER HEAD COVER(S) - REMOVAL).
(9) Remove rocker arm and lifter assemblies from
lifter bores.
Fig. 32 CYLINDER HEAD ASSEMBLY
1 - VALVE SPRING
2 - CYLINDER HEAD BOLT
3 - GLOW PLUG
4 - COOLANT TEMPERATURE SENSOR
5 - CYLINDER HEAD ALIGNMENT DOWEL
6 - CYLINDER BLOCK
7 - CYLINDER LINER
8 - ENGINE BLOCK DECK
9 - CYLINDER HEAD GASKET
10 - CYLINDER HEAD
11 - ROCKER ARM AND LIFTER ASSEMBLY
Fig. 33 CYLINDER HEAD COVER/INTAKE
MANIFOLD
1 - CYLINDER HEAD COVER/INTAKE MANIFOLD BOLTS(LONG)
2 - CYLINDER HEAD COVER/INTAKE MANIFOLD
3 - CYLINDER HEAD
4 - CYLINDER HEAD COVER/INTAKE MANIFOLD GASKET
5 - CYLINDER HEAD COVER/INTAKE MANIFOLD
BOLTS(SHORT)
9a - 30 ENGINE 2.5L TURBO DIESELRG

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 oxygen
sensor 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
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.
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
²Inlet/Intake air temperature (IAT)
²MAP
²Throttle position
RSFUEL INJECTION14-17
FUEL INJECTION (Continued)

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)
²Inlet/Intake air temperature (IAT)
²Crankshaft position (engine speed)
²Camshaft position
²Knock 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:
²Inlet/Intake 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
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
²All inputs monitored for proper voltage range.
²All monitored components (refer to the Emission
section for On-Board Diagnostics).
The PCM compares the upstream and downstream
heated oxygen sensor inputs to measure catalytic
convertor efficiency. If the catalyst efficiency drops
below the minimum acceptable percentage, the PCM
stores a diagnostic trouble code in memory.
During certain idle conditions, the PCM may enter
a variable idle speed strategy. During variable idle
speed strategy the PCM adjusts engine speed based
on the following inputs.
²A/C sense
²Battery voltage
²Battery temperature
²Engine coolant temperature
²Engine run time
²Inlet/Intake air temperature
²Vehicle mileageACCELERATION MODE
This is a CLOSED LOOP mode. The PCM recog-
nizes an abrupt increase in Throttle Position sensor
output voltage or MAP sensor output voltage as a
demand for increased engine output and vehicle
acceleration. The PCM increases injector pulse width
in response to increased fuel demand.
DECELERATION MODE
This is a CLOSED LOOP mode. During decelera-
tion the following inputs are received by the PCM:
²A/C sense
²Battery voltage
²Inlet/Intake air temperature
²Engine coolant temperature
²Crankshaft position (engine speed)
²Exhaust gas oxygen content (upstream heated
oxygen sensor)
²Knock sensor
²Manifold absolute pressure
²Throttle position
²IAC motor control changes in response to MAP
sensor feedback
The PCM may receive a closed throttle input from
the Throttle Position Sensor (TPS) when it senses an
abrupt decrease in manifold pressure. This indicates
a hard deceleration. In response, the PCM may
14 - 18 FUEL INJECTIONRS
FUEL INJECTION (Continued)

momentarily turn off the injectors. This helps
improve fuel economy, emissions and engine braking.
WIDE-OPEN-THROTTLE MODE
This is an OPEN LOOP mode. During wide-open-
throttle operation, the following inputs are used by
the PCM:
²Inlet/Intake air temperature
²Engine coolant temperature
²Engine speed
²Knock sensor
²Manifold absolute pressure
²Throttle position
When the PCM senses a wide-open-throttle condi-
tion through the Throttle Position Sensor (TPS) it de-
energizes the A/C compressor clutch relay. This
disables the air conditioning system.
The PCM does not monitor the heated oxygen sen-
sor inputs during wide-open-throttle operation except
for downstream heated oxygen sensor and both
shorted diagnostics. The PCM adjusts injector pulse
width to supply a predetermined amount of addi-
tional fuel.
IGNITION SWITCH OFF MODE
When the operator turns the ignition switch to the
OFF position, the following occurs:
²All outputs are turned off, unless 02 Heater
Monitor test is being run. Refer to the Emission sec-
tion for On-Board Diagnostics.
²No inputs are monitored except for the heated
oxygen sensors. The PCM monitors the heating ele-
ments in the oxygen sensors and then shuts down.
FUEL CORRECTION or ADAPTIVE MEMORIES
DESCRIPTION
In Open Loop, the PCM changes pulse width with-
out feedback from the O2 Sensors. Once the engine
warms up to approximately 30 to 35É F, the PCM
goes into closed loopShort Term Correctionand
utilizes feedback from the O2 Sensors. Closed loop
Long Term Adaptive Memoryis maintained above
170É to 190É F unless the PCM senses wide open
throttle. At that time the PCM returns to Open Loop
operation.
OPERATION
Short Term
The first fuel correction program that begins func-
tioning is the short term fuel correction. This system
corrects fuel delivery in direct proportion to the read-
ings from the Upstream O2 Sensor.The PCM monitors the air/fuel ratio by using the
input voltage from the O2 Sensor. When the voltage
reaches its preset high or low limit, the PCM begins
to add or remove fuel until the sensor reaches its
switch point. The short term corrections then begin.
The PCM makes a series of quick changes in the
injector pulse-width until the O2 Sensor reaches its
opposite preset limit or switch point. The process
then repeats itself in the opposite direction.
Short term fuel correction will keep increasing or
decreasing injector pulse-width based upon the
upstream O2 Sensor input. The maximum range of
authority for short term memory is 25% (+/-) of base
pulse-width.
Long Term
The second fuel correction program is the long
term adaptive memory. In order to maintain correct
emission throughout all operating ranges of the
engine, a cell structure based on engine rpm and load
(MAP) is used.
Ther number of cells varies upon the driving con-
ditions. Two cells are used only during idle, based
upon TPS and Park/Neutral switch inputs. There
may be two other cells used for deceleration, based
on TPS, engine rpm, and vehicle speed. The other
twelve cells represent a manifold pressure and an
rpm range. Six of the cells are high rpm and the
other six are low rpm. Each of these cells is a specific
MAP voltage range .
As the engine enters one of these cells the PCM
looks at the amount of short term correction being
used. Because the goal is to keep short term at 0 (O2
Sensor switching at 0.5 volt), long term will update
in the same direction as short term correction was
moving to bring the short term back to 0. Once short
term is back at 0, this long term correction factor is
stored in memory.
The values stored in long term adaptive memory
are used for all operating conditions, including open
loop. However, the updating of the long term memory
occurs after the engine has exceeded approximately
17É F, with fuel control in closed loop and two min-
utes of engine run time. This is done to prevent any
transitional temperature or start-up compensations
from corrupting long term fuel correction.
Long term adaptive memory can change the pulse-
width by as much as 25%, which means it can correct
for all of short term. It is possible to have a problem
that would drive long term to 25% and short term to
another 25% for a total change of 50% away from
base pulse-width calculation.
RSFUEL INJECTION14-19
FUEL INJECTION (Continued)