heater CHRYSLER CARAVAN 2003 Manual PDF

(47) Connect the radiator upper hose.
(48) Connect the heater hoses. Remove pinch-off
pliers from the rear heater hoses (if equipped).
(49) Install the radiator upper support crossmem-
ber (Refer to 23 - BODY/EXTERIOR/GRILLE OPEN-
ING REINFORCEMENT - INSTALLATION).
(50) Install the wiper module (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(51) Connect the fuel line to fuel rail (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/FUEL LINES -
STANDARD PROCEDURE).
(52) Install the air cleaner and hoses.
(53) Install new oil filter. Fill engine crankcase
with proper oil to correct level.
(54) Connect negative cable to battery.
(55) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(56) Start engine and run until operating temper-
ature is reached.
(57) Adjust transmission linkage, if necessary.
SPECIFICATIONS
3.3/3.8L ENGINE
DESCRIPTION SPECIFICATION
General Specification
Type 60É V-6 Engine
Number of Cylinders 6
Displacement
Ð3.3L 3.3 Liters
(201 cu. in.)
Ð3.8L 3.8 Liters
(231 cu. in.)
Bore
Ð3.3L 93.0 mm
(3.66 in.)
Ð3.8L 96.0 mm
(3.779 in.)
Stroke
Ð3.3L 81.0 mm
(3.188 in.)
Ð3.8L 87.0 mm
(3.425 in.)
Compression Ratio
Ð3.3L 9.35:1
Ð3.8L 9.6:1
DESCRIPTION SPECIFICATION
Firing Order 1-2-3-4-5-6
Cylinder Number (Front
to Rear)
ÐFront Bank 2,4,6
ÐRear Bank 1,3,5
Compression PressureÐ
Minimum689.5 kPa
(100 psi)
Max. Variation Between
Cylinders25%
Cylinder Block
Cylinder Bore Diameter
(Standard)
Ð3.3L 92.993±93.007 mm
(3.661±3.6617 in.)
Ð3.8L 95.993±96.007 mm
(3.7792±3.780 in.)
Out-of-Round (Service
Limits)0.076 mm
(0.003 in.)
Taper (Service Limits) 0.051 mm
(0.002 in.)
Lifter Bore Diameter 22.980±23.010 mm
(0.905±0.906 in.)
Deck Surface Flatness
(Max.)0.1 mm
(0.004 in.)
Pistons
Piston Diameter
Ð3.3L ÐMeasured 39.8
mm (1.567 in.) from
piston top92.968±92.998 mm
(3.660±3.661 in.)
Ð3.8L ÐMeasured 33.01
mm (1.30 in.) from piston
top95.968±95.998 mm
(3.778±3.779 in.)
Clearance in Bore @
Size Location (New)-0.005±0.039 mm
(-0.0002±0.0015 in.)
Weight
Ð3.3L 362  5 grams
(12.77  0.1764 oz.)
Ð3.8L 426  5 grams
(15.03  0.1764 oz.)
Piston Pins
Type Press Fit in Rod
(Serviced as an
Assembly)
RSENGINE 3.3/3.8L9-91
ENGINE 3.3/3.8L (Continued)
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OIL COOLER & LINES
DESCRIPTION
An engine oil cooler is used on 3.3/3.8L engines
(Heavy Duty Cooling Only) (Fig. 98). The cooler is a
coolant-to-oil type and mounted between the oil filter
and engine block.
OPERATION
Engine oil travels from the oil filter and into the
oil cooler. Engine oil then exits the cooler into the
main gallery. Engine coolant flows into the cooler
from the heater return tube and exits into the water
pump inlet.
REMOVAL
(1) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE - COOLING SYSTEM
DRAINING).
(2) Disconnect oil cooler inlet and outlet hoses
(Fig. 97).
(3) Remove oil filter.
(4) Remove oil cooler attachment fitting (Fig. 98).
(5) Remove oil cooler.
INSTALLATION
(1) Lubricate seal and position oil cooler to connec-
tor fitting on oil filter adapter (Fig. 98).NOTE: Position the flat side of oil cooler parallel to
oil pan rail.
(2) Install oil cooler attachment fitting and tighten
to 27 N´m (20 ft. lbs.) (Fig. 98).
(3) Install oil filter.
(4) Connect oil cooler inlet and outlet hoses (Fig.
97).
Fig. 96 Engine Oil Level Dipstick and Fill Locations
1 - COOLANT RECOVERY CONTAINER 3 - ENGINE OIL LEVEL DIPSTICK
2 - ENGINE OIL FILL CAP 4 - RADIATOR PRESSURE CAP
Fig. 97 Engine Oil Cooler Hoses
1 - OIL COOLER INLET TUBE
2 - INLET HOSE
3 - OIL COOLER OUTLET TUBE
4 - OUTLET HOSE
5 - WATER PUMP INLET TUBE
9 - 138 ENGINE 3.3/3.8LRS
OIL (Continued)
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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. 115).
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.
(11) Install air cleaner and air inlet hose assembly.
(12) Connect the inlet air temperature (IAT) sen-
sor electrical connector.
(13) Connect battery negative cable.
INTAKE MANIFOLD - LOWER
REMOVAL - LOWER INTAKE MANIFOLD
(1) Perform fuel system pressure release procedure
(before attempting any repairs).(Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY - STANDARD
PROCEDURE)
(2) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(3) Remove the upper intake manifold. (Refer to 9
- ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL)
(4) Remove the fuel line. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/FUEL LINES - STANDARD
PROCEDURE) (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE)
(5) Remove ignition coil and bracket (Fig. 119).
(6) Disconnect heater supply hose and engine cool-
ant temperature sensor (Fig. 120).
(7) Disconnect the fuel injector wire harness.
(8) Remove the fuel injectors and rail assembly
(Fig. 119).
(9) Remove radiator upper hose.
(10) Remove the intake manifold bolts.
(11) Remove lower intake manifold (Fig. 121).WARNING: INTAKE MANIFOLD GASKET IS MADE
OF VERY THIN METAL AND MAY CAUSE PER-
SONAL INJURY, HANDLE WITH CARE.
(12) Remove intake manifold seal retainers screws
(Fig. 121). Remove intake manifold gasket.
(13) Inspect and clean manifold. (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSPECTION) (Refer to 9 - ENGINE/MANIFOLDS/
INTAKE MANIFOLD - CLEANING)
CLEANING
(1) Discard gasket(s).
(2) Clean all sealing surfaces.
INSPECTION
Check for:
²Damage and cracks of each section.
²Clogged water passages in end cross-overs (if
equipped).
Fig. 119 FUEL RAIL AND IGNITION COIL &
BRACKET
1 - FUEL RAIL
2 - BOLT - FUEL RAIL
3 - NUT - IGNITION COIL
4 - BOLT - IGNITION COIL
5 - IGNITION COIL
6 - BRACKET - IGNITION COIL
7 - STUD - IGNITION COIL
8 - SEPARATOR - SPARK PLUG CABLE
9 - BRACKET - SPARK PLUG CABLE SEPARATOR
10 - BOLT - SEPARATOR BRACKET
11 - BRACKET - SPARK PLUG CABLE SEPARATOR
9 - 148 ENGINE 3.3/3.8LRS
INTAKE MANIFOLD - UPPER (Continued)
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²Check for cylinder head mounting surface distor-
tion using a straightedge and thickness gauge. (Refer
to 9 - ENGINE/CYLINDER HEAD - INSPECTION)
INSTALLATION - LOWER INTAKE MANIFOLD
(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. 122).
(2) Carefully install the new intake manifold gas-
ket (Fig. 121). Tighten end seal retainer screws to 12
N´m (105 in. lbs.).
(3) Install lower intake manifold (Fig. 121). 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. 123). 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. 120).
(7) Connect the heater supply (Fig. 120) 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.
Fig. 120 ECT SENSOR & HEATER SUPPLY
1 - ENGINE COOLANT TEMPERATURE SENSOR
2 - CONNECTOR - ENGINE COOLANT SENSOR
3 - FITTING - HEATER SUPPLY
Fig. 121 INTAKE MANIFOLD - LOWER
1 - INTAKE MANIFOLD - LOWER
2 - BOLT - GASKET END SEAL RETAINER
3 - GASKET
4 - BOLT - LOWER INTAKE MANIFOLD
Fig. 122 Intake Manifold Gasket Sealing
1 - SEALER LOCATIONS
RSENGINE 3.3/3.8L9 - 149
INTAKE MANIFOLD - LOWER (Continued)
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VALVE TIMING
STANDARD PROCEDURE
STANDARD PROCEDURE - VALVE TIMING
VERIFICATION
(1) Remove front cylinder head cover and all 6
spark plugs.
(2) Rotate engine until the #2 piston is at TDC of
the compression stroke.
(3) Install a degree wheel on the crankshaft pulley.
(4) With proper adaptor, install a dial indicator
into #2 spark plug hole. Using the indicator find TDC
on the compression stroke.
(5) Position the degree wheel to zero.
(6) Remove dial indicator from spark plug hole.
(7) Place a 5.08 mm (0.200 in.) spacer between the
valve stem tip of #2 intake valve and rocker arm pad.
Allow tappet to bleed down to give a solid tappet
effect.
(8) Install a dial indicator so plunger contacts the
#2 intake valve spring retainer as nearly perpendic-
ular as possible. Zero the indicator.
(9) Rotate the engine clockwise until the intake
valve has lifted .254 mm (0.010 in.).
CAUTION: Do not turn crankshaft any further clock-
wise as intake valve might bottom and result in
serious damage.
(10) Degree wheel should read 6 degrees BTDC to
6 degrees ATDC.
STANDARD PROCEDURE - MEASURING
TIMING CHAIN WEAR
NOTE: This procedure must be performed with the
timing chain cover removed (Refer to 9 - ENGINE/
VALVE TIMING/TIMING CHAIN COVER - REMOVAL).
(1) Position a scale next to timing chain so that
any movement of chain may be measured (Fig. 132).
(2) Position a torque wrench and socket on the
camshaft sprocket attaching bolt. Apply force in the
direction of crankshaft rotation to take up slack to
the following torque:
²41 N´m (30 ft. lb.) with cylinder heads installed
²20 N´m (15 ft. lb.) with cylinder heads removed
NOTE: With torque applied to the camshaft
sprocket bolt, crankshaft should not be permitted to
move. It may be necessary to block crankshaft to
prevent rotation.
(3) Holding a measuring scale along edge of chain
links (Fig. 132).(4) Apply force in the reverse direction to the fol-
lowing torque:
²41 N´m (30 ft. lb.) with cylinder heads installed
²20 N´m (15 ft. lb.) with cylinder heads removed
(5) Measure amount of sprocket/chain movement.
(6) Install a new timing chain and sprockets if
movement exceeds 3.175 mm (1/8 in.).
TIMING CHAIN COVER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Drain cooling system. (Refer to 7 - COOLING -
STANDARD PROCEDURE)
(3) Raise vehicle on hoist.
(4) Drain engine oil.
(5) Remove right wheel and inner splash shield.
(6) Remove oil pan. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PAN - REMOVAL)
(7) Remove oil pick-up tube (Fig. 133).
(8) Remove accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL)
(9) Remove A/C compressor and set aside.
(10) Remove crankshaft vibration damper. (Refer
to 9 - ENGINE/ENGINE BLOCK/VIBRATION
DAMPER - REMOVAL)
(11) Remove radiator lower hose.
(12) Remove heater hose from timing chain cover
housing (Fig. 134) or water pump inlet tube (if
engine oil cooler equipped) (Fig. 135).
(13) Remove the right side engine mount. (Refer to
9 - ENGINE/ENGINE MOUNTING/RIGHT MOUNT
- REMOVAL)
(14) Remove idler pulley from engine bracket (Fig.
136).
(15) Remove the engine mount bracket (Fig. 136).
Fig. 132 Measuring Timing Chain Wear
1 - TORQUE WRENCH
RSENGINE 3.3/3.8L9 - 153
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(16) Remove camshaft position sensor from timing
chain cover (Fig. 136).
Fig. 133 OIL PICKUP TUBE
1 - BOLT
2 - OIL PICK-UP TUBE
3 - O-RING
Fig. 134 HEATER RETURN HOSE (Without Engine
Oil Cooler)
1 - CAP AND CLAMP (OIL COOLER EQUIPPED ONLY)
2 - HOSE ASSEMBLY - HEATER RETURN
3 - BOLT - HEATER TUBE ATTACHING
4 - BOLT - HEATER TUBE ATTACHING
Fig. 135 HEATER HOSES 3.3/3.8L (With Engine Oil
Cooler)
1 - HOSE - HEATER SUPPLY
2 - HOSE - HEATER RETURN
3 - TUBE ASSEMBLY - HEATER RETURN
4 - BOLT - TUBE ASSEMBLY
5 - BOLT - TUBE ASSEMBLY
6 - HOSE - HEATER RETURN/OIL COOLER OUTLET
Fig. 136 Engine Mount Bracket
1 - CAMSHAFT SENSOR
2 - BOLT - CAMSHAFT SENSOR
3 - BOLT - MOUNT BRACKET (VERTICAL)
4 - BRACKET - ENGINE MOUNT
5 - BOLT - MOUNT BRACKET (HORIZONTAL)
6 - PULLEY - IDLER
7 - BOLT - IDLER PULLEY
8 - SPACER - IDLER PULLEY BOLT
9 - BOLT - MOUNT BRACKET (HORIZONTAL)
9 - 154 ENGINE 3.3/3.8LRS
TIMING CHAIN COVER (Continued)
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(17) Remove the water pump for cover removal
clearance. (Refer to 7 - COOLING/ENGINE/WATER
PUMP - REMOVAL)
(18) Remove the bolt attaching the power steering
pump support strut to the front cover (Fig. 137).
(19) Remove the timing chain cover fasteners.
Remove timing chain cover (Fig. 138).
INSTALLATION
(1) Be sure mating surfaces of chain case cover
and cylinder block are clean and free from burrs.
Crankshaft oil seal must be removed to insure cor-
rect oil pump engagement.
NOTE: DO NOT USE SEALER ON COVER GASKET
(2) Position new gasket on timing cover (Fig. 138).
Adhere new gasket to chain case cover, making sure
that the lower edge of the gasket is flush to 0.5 mm
(0.020 in.) passed the lower edge of the cover.
(3) Rotate crankshaft so that the oil pump drive
flats are in the vertical position.
(4) Position oil pump inner rotor so the mating
flats are in the same position as the crankshaft drive
flats (Fig. 138).
CAUTION: Make sure the oil pump is engaged on
the crankshaft correctly or severe damage may
result.
(5) Install timing cover (Fig. 138).
(6) Install timing chain cover bolts. Tighten M8
bolts to 27 N´m (20 ft. lbs.) and M10 bolts to 54 N´m
(40 ft. lbs.) (Fig. 139).
(7) Install crankshaft front oil seal. (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT OIL
SEAL - FRONT - INSTALLATION)
(8) Install water pump and pulley. (Refer to 7 -
COOLING/ENGINE/WATER PUMP - INSTALLA-
TION)(9) Install crankshaft vibration damper. (Refer to 9
- ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION)
(10) Install engine mount bracket (Fig. 136) and
tighten M10 to 54 N´m (40 ft. lbs.), M8 bolt to 28
N´m (21 ft. lb. lbs.).
(11) Install idler pulley on engine mount bracket
(Fig. 136).
(12) Install right side engine mount. (Refer to 9 -
ENGINE/ENGINE MOUNTING/RIGHT MOUNT -
INSTALLATION)
(13) Install camshaft position sensor (Refer to 8 -
ELECTRICAL/IGNITION CONTROL/CAMSHAFT
POSITION SENSOR - INSTALLATION).
(14) Connect the heater return hose at rear of tim-
ing chain cover (Fig. 134) or at water pump inlet
tube (if engine oil cooler equipped) (Fig. 135).
(15) Connect the radiator lower hose.
(16) Install A/C compressor.
(17) Install accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION)
(18) Install oil pump pick-up tube with new
O-ring. Tighten attaching bolt to 28 N´m (250 in.
lbs.).
(19) Install oil pan. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PAN - INSTALLATION)
(20) Install inner splash shield and right front
wheel.
(21) Fill crankcase with engine oil to proper level.
(22) Fill cooling system. (Refer to 7 - COOLING -
STANDARD PROCEDURE)
(23) Connect negative cable to battery.
Fig. 137 Power Steering Pump Strut
1 - BOLT - LOWER
2 - STRUT - P/S PUMP
3 - BOLT - UPPER
Fig. 138 Timing Chain Cover and Gasket
1 - GASKET
2 - TIMING CHAIN COVER
RSENGINE 3.3/3.8L9 - 155
TIMING CHAIN COVER (Continued)
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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 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)
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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, after 2
trips.
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 status
²Battery voltage
²Battery temperature or Calculated Battery Tem-
perature
²Engine coolant temperature
²Engine run time
²Inlet/Intake air temperature
²Vehicle mileage
ACCELERATION 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.
²Wide Open Throttle-open loop
DECELERATION MODE
This is a CLOSED LOOP mode. During decelera-
tion the following inputs are received by the PCM:
²A/C status
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 sensor
²IAC motor (solenoid) 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 (Open Loop). In response, the
PCM may 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 and disables
EGR (if equipped).
The PCM adjusts injector pulse width to supply a
predetermined amount of additional fuel, based on
MAP and RPM.
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
14 - 20 FUEL INJECTIONRS
FUEL INJECTION (Continued)
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capacity and converter efficiency. Also, the PCM uses
the upstream heated oxygen sensor input when
adjusting injector pulse width.
When the catalytic converter efficiency drops below
emission standards, the PCM stores a diagnostic
trouble code and illuminates the malfunction indica-
tor lamp (MIL).
The O2 sensors produce voltages from 0 to 1 volt
(this voltage is offset by a constant 2.5 volts on NGC
vehicles), depending upon the oxygen content of the
exhaust gas. When a large amount of oxygen is
present (caused by a lean air/fuel mixture, can be
caused by misfire and exhaust leaks), the sensors
produces a low voltage. When there is a lesser
amount of oxygen present (caused by a rich air/fuel
mixture, can be caused by internal engine problems)it produces a higher voltage. By monitoring the oxy-
gen content and converting it to electrical voltage,
the sensors act as a rich-lean switch.
The oxygen sensors are equipped with a heating
element that keeps the sensors at proper operating
temperature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into closed loop operation sooner.
Also, it allows the system to remain in closed loop
operation during periods of extended idle.
In Closed Loop operation the PCM monitors the O2
sensors input (along with other inputs) and adjusts
the injector pulse width accordingly. During Open
Loop operation the PCM ignores the O2 sensor input.
The PCM adjusts injector pulse width based on pre-
programmed (fixed) values and inputs from other
sensors.
1.6L Siemens controller and SBEC controller - The
Automatic Shutdown (ASD) relay supplies battery
voltage to both the upstream and downstream heated
oxygen sensors. The oxygen sensors are equipped
with a heating element. The heating elements reduce
the time required for the sensors to reach operating
temperature. The PCM uses pulse width modulation
to control the ground side of the heater to regulate
the temperature on 4 cyl. upstream O2 heater only.
NGC Controller - Has a common ground for the
heater in the O2S. 12 volts is supplied to the heater
in the O2S by the NGC controller. Both the upstream
and downstream O2 sensors for NGC are pulse width
modulation (PWM).
UPSTREAM OXYGEN SENSOR
The input from the upstream heated oxygen sensor
tells the PCM the oxygen content of the exhaust gas.
Fig. 22 O2 SENSOR UPSTREAM 1/1 - 2.4L
Fig. 23 O2 SENSOR UPSTREAM 1/1 - 3.3/3.8L
Fig. 24 O2 SENSOR DOWNSTREAM 1/2 - 2.4/3.3/
3.8L
14 - 32 FUEL INJECTIONRS
O2 SENSOR (Continued)
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