Egr CHRYSLER VOYAGER 1996 Service Manual

INTAKE AIR TEMPERATURE SENSORÐ2.4L
The intake air temperature sensor threads into the
intake manifold plenum (Fig. 133).
REMOVAL
(1) Remove electrical connector from sensor.
(2) Remove sensor.
INSTALLATION
(1) Install sensor. Tighten sensor to 28 N´m (20 ft.
lbs.) torque.
(2) Attach electrical connector to sensor.
SPECIFICATIONS
TORQUE
DESCRIPTION TORQUE
Generator Brkt. to Intake Manifold BoltsÐ3.3/3.8L.54
N´m (40 ft. lbs.)
Coolant SensorÐ2.4L..........7N´m(62in.lbs.)
Coolant SensorÐ3.0L..........7N´m(62in.lbs.)
Coolant SensorÐ3.3/3.8L........7N´m(62in.lbs.)
Cly. Head to Intake Manifold
Strut BoltsÐ3.3/3.8L........54N´m(40ft.lbs.)
EGR Tube to Intake Manifold
Screws..................22N´m(200 in. lbs.)
Idle Air Control Motor..........2N´m(18in.lbs.)
Ignition Coil Fasteners.......12N´m(105 in. lbs.)
Intake Air Temperature Sensor . .28 N´m (20 ft. lbs.)
MAP SensorÐ2.4L............4N´m(35in.lbs.)
MAP SensorÐ3.0L............4N´m(35in.lbs.)
MAP SensorÐ3.3/3.8L..........4N´m(35in.lbs.)
Upstream O2S...............27N´m(20ft.lbs.)
Downstream O2S.............27N´m(20ft.lbs.)
Throttle Body Bolts..........26N´m(225 in. lbs.)
SPECIAL TOOLS
FUEL
Fig. 133 Intake Air Temperature Sensor
Extractor C±4334
Pressure Gauge Assembly C±4799±B
Fuel Pressure Test Adapter 6539
Spanner Wrench 6856
14 - 72 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

For periodic draining of water from the bowl, refer
to Fuel Filter/Water Separator Removal/Installation
in this group.
FUEL SHUTDOWN SOLENOID
The fuel shutdown solenoid is controlled and
operated by the PCM.
The fuel shutdown (shut-off) solenoid is used to
electrically shut off the diesel fuel supply to the high-
pressure fuel injection pump. The solenoid is
mounted to the rear of the injection pump (Fig. 4).
The solenoid controls starting and stopping of the
engine regardless of the position of the accelerator
pedal. When the ignition (key) switch is OFF, the
solenoid is shut off and fuel flow is not allowed to the
fuel injection pump. When the key is placed in the
ON or START positions, fuel supply is allowed at the
injection pump.
FUEL INJECTION PUMP
The fuel injection pump is a mechanical distribu-
tor±type, Bosch VP36 series (Fig. 5). A gear on the
end of the injection pump shaft meshes with the
drive gear at the front of engine. The pump is
mechanically timed, relative to the position of the
cam and crankshaft. The PCM can make adjust-
ments to the timing of the injection pump.
The injection pump contains the fuel shutdown
solenoid, fuel temperature sensor, control sleeve sen-
sor, fuel quantity actuator and the fuel timing sole-
noid (Fig. 5).In the electronically controlled injection pump, the
pump plunger works the same as the pump plunger
in a mechanically controlled injection pump, but the
amount of fuel and the time the fuel is injected is
controlled by the vehicle's PCM, instead of by a
mechanical governor assembly. A solenoid controlled
by the PCM is used in place of the mechanical gov-
ernor assembly, and it moves a control sleeve inside
the pump that regulates the amount of fuel being
injected. There is no mechanical connection between
the accelerator pedal and the electronically controlled
injection pump. Instead, a sensor connected to the
accelerator pedal sends a signal to the PCM that rep-
resents the actual position of the accelerator pedal.
The PCM uses this input, along with input from
other sensors to move the control sleeve to deliver
the appropriate amount of fuel. This system is known
as ªDrive-By-Wireº
The actual time that the fuel is delivered is very
important to the diesel combustion process. The PCM
monitors outputs from the engine speed sensor (fly-
wheel position in degrees), and the fuel injector sen-
sor (mechanical movement within the #1 cylinder
fuel injector). Outputs from the Accelerator Pedal
Position sensor, engine speed sensor (engine rpm)
and engine coolant temperature sensor are also used.
The PCM will then compare its set values to these
outputs to electrically adjust the amount of fuel tim-
ing (amount of advance) within the injection pump.
This is referred to as ªClosed Loopº operation. The
PCM monitors fuel timing by comparing its set value
to when the injector #1 opens. If the value is greater
than a preset value a fault will be set.
Fig. 4 Fuel Shutdown Solenoid and Overflow Valve
Location
Fig. 5 Fuel Injection Pump
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 5
DESCRIPTION AND OPERATION (Continued)

FUEL INJECTION SYSTEMÐ2.0L ENGINE
INDEX
page page
GENERAL INFORMATION
INTRODUCTIONÐ2.0L ENGINE............ 32
MODES OF OPERATIONÐ2.0L ENGINE..... 32
DESCRIPTION AND OPERATION
AIR CONDITIONING (A/C) RELAYÐPCM
OUTPUTÐ2.0L ENGINE................ 35
AIR CONDITIONING PRESSURE
TRANSDUCERÐPCM INPUTÐ
2.0L ENGINE......................... 33
AIR CONDITIONING SWITCH SENSEÐ
PCM INPUTÐ2.0L ENGINE.............. 33
AUTOMATIC SHUTDOWN (ASD) SENSEÐ
PCM INPUTÐ2.0L ENGINE.............. 33
AUTOMATIC SHUTDOWN RELAYÐ
PCM OUTPUTÐ2.0L ENGINE............ 35
BATTERY VOLTAGEÐPCM INPUTÐ
2.0L ENGINE......................... 33
CAMSHAFT POSITION SENSORÐ
PCM INPUTÐ2.0L ENGINE.............. 33
CRANKSHAFT POSITION SENSORÐ
PCM INPUTÐ2.0L ENGINE.............. 33
DATA LINK CONNECTORÐPCM OUTPUTÐ
2.0L ENGINE......................... 35
ELECTRONIC EGR TRANSDUCERÐ
PCM OUTPUTÐ2.0L ENGINE............ 35
ENGINE COOLANT TEMPERATURE SENSORÐ
PCM INPUTÐ2.0L ENGINE.............. 33
FUEL INJECTORSÐPCM OUTPUTÐ
2.0L ENGINE......................... 35
FUEL PUMP RELAYÐPCM OUTPUTÐ
2.0L ENGINE......................... 35
GENERATOR FIELDÐPCM OUTPUTÐ
2.0L ENGINE......................... 35
HEATED OXYGEN SENSORÐPCM INPUTÐ
2.0L ENGINE......................... 33
IDLE AIR CONTROL MOTORÐPCM OUTPUTÐ
2.0L ENGINE......................... 35
IGNITION COILÐPCM OUTPUTÐ
2.0L ENGINE......................... 36KNOCK SENSORÐPCM INPUTÐ
2.0L ENGINE......................... 34
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUTÐ2.0L ENGINE...... 36
MANIFOLD ABSOLUTE PRESSURE
(MAP SENSOR)ÐPCM INPUTÐ
2.0L ENGINE......................... 34
POWERTRAIN CONTROL MODULEÐ
2.0L ENGINE......................... 33
RADIATOR FAN CONTROL MODULEÐ
PCM OUTPUTÐ2.0L ENGINE............ 36
SPEED CONTROL SOLENOIDSÐ
PCM OUTPUTÐ2.0L ENGINE............ 36
SPEED CONTROLÐPCM INPUTÐ
2.0L ENGINE......................... 34
STARTER RELAYÐPCM OUTPUTÐ
2.0L ENGINE......................... 35
SYSTEM DIAGNOSISÐ2.0L ENGINE........ 33
TACHOMETERÐPCM OUTPUTÐ
2.0L ENGINE......................... 36
THROTTLE BODYÐ2.0L ENGINE.......... 36
THROTTLE POSITION SENSOR/ IDLE AIR
CONTROL MOTORÐPCM INPUTÐ
2.0L ENGINE......................... 35
DIAGNOSIS AND TESTING
ASD AND FUEL PUMP RELAYSÐ
2.0L ENGINE......................... 39
CAMSHAFT AND CRANKSHAFT
POSITION SENSOR................... 40
ENGINE COOLANT TEMPERATURE
SENSOR............................ 40
KNOCK SENSORÐ2.0L ENGINE........... 40
MANIFOLD ABSOLUTE PRESSURE
(MAP) SENSORÐ2.0L ENGINE........... 39
THROTTLE BODY MINIMUM AIR FLOW..... 41
THROTTLE POSITION SENSOR........... 40
VISUAL INSPECTIONÐSOHC............. 36
SPECIFICATIONS
TORQUE............................. 42
GENERAL INFORMATION
INTRODUCTIONÐ2.0L ENGINE
Refer to the Introduction for 2.4/3.0/3.3/3.8L
engines under General Information in the Fuel Injec-
tion System section of group 14 for more information.
MODES OF OPERATIONÐ2.0L ENGINE
Refer to the Modes of Operation for 2.4/3.0/3.3/3.8L
engines under General Information in the Fuel Injec-
tion System section of group 14 for more information.
14 - 32 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS

THROTTLE POSITION SENSOR/ IDLE AIR
CONTROL MOTORÐPCM INPUTÐ2.0L ENGINE
Refer to the Throttle Control and Idle Air Control
motor for the 2.4/3.0/3.3/3.8L engines under Descrip-
tion and Operation in the Fuel Injection System sec-
tion of group 14 for more information.
AIR CONDITIONING (A/C) RELAYÐPCM
OUTPUTÐ2.0L ENGINE
Refer to the Air Conditioning relay for 2.4/3.0/3.3/
3.8L engines under Description and Operation in the
Fuel Injection System section of group 14 for more
information.
GENERATOR FIELDÐPCM OUTPUTÐ2.0L ENGINE
Refer to Generator Field for 2.4/3.0/3.3/3.8L
engines under Description and Operation in the Fuel
Injection System section of group 14 for more infor-
mation.
AUTOMATIC SHUTDOWN RELAYÐPCM
OUTPUTÐ2.0L ENGINE
Refer to Automatic Shutdown Relay for 2.4/3.0/3.3/
3.8L engines under Description and Operation in the
Fuel Injection System section of group 14 for more
information.
FUEL PUMP RELAYÐPCM OUTPUTÐ2.0L ENGINE
Refer to the Fuel Pump Relay for 2.4/3.0/3.3/3.8L
engines under Description and Operation in the Fuel
Injection System section of group 14 for more infor-
mation.
STARTER RELAYÐPCM OUTPUTÐ2.0L ENGINE
Refer to the Starter Relay for 2.4/3.0/3.3/3.8L
engines under Description and Operation in the Fuel
Injection System section of group 14 for more infor-
mation.
IDLE AIR CONTROL MOTORÐPCM OUTPUTÐ2.0L
ENGINE
Refer to the Idle Air Control Motor for 2.4/3.0/3.3/
3.8L engines under Description and Operation in the
Fuel Injection System section of group 14 for more
information. Refer to (Fig. 8) for component location
ELECTRONIC EGR TRANSDUCERÐPCM
OUTPUTÐ2.0L ENGINE
Refer to the Electronic EGR Transducer for 2.4/3.0/
3.3/3.8L engines under Description and Operation in
the Fuel Injection System section of group 14 for
more information.
DATA LINK CONNECTORÐPCM OUTPUTÐ2.0L
ENGINE
Refer to the Data Link Connector for 2.4/3.0/3.3/
3.8L engines under Description and Operation in the
Fuel Injection System section of group 14 for more
information.
FUEL INJECTORSÐPCM OUTPUTÐ2.0L ENGINE
Refer to the Fuel Injectors for 2.4/3.0/3.3/3.8L
engines under Description and Operation in the Fuel
Injection System section of group 14 for more infor-
mation.
Fig. 8 Throttle Position Sensor/Idle Air Control
motorÐ2.0L engine
Fig. 9 Electronic EGR TransducerÐ2.0L engine
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 35
DESCRIPTION AND OPERATION (Continued)

(13) Check the electrical connection at the knock
sensor (Fig. 18).
(14) Check the electrical connections at the cam-
shaft position sensor and engine coolant temperature
sensor (Fig. 19).
(15) Check the electrical connector at the Elec-
tronic EGR Transducer. Inspect the vacuum and back
pressure hoses at the solenoid and transducer for
leaks (Fig. 20).
(16) Inspect the electrical connections at the gen-
erator (Fig. 21). Check the generator belt for glazing
or damage.(17) Inspect the electrical connector at the crank-
shaft position sensor (Fig. 22).
(18) Check the electrical connection at the vehicle
speed sensor (Fig. 23).
Fig. 12 Idle Air Control Motor and Throttle Position
SensorÐTypical
Fig. 13 PCV Valve
Fig. 14 MAP/Intake Air Temperature Sensor
Fig. 15 Fuel Injectors
Fig. 16 Ignition Coil and Spark PlugsÐTypical
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 37
DIAGNOSIS AND TESTING (Continued)

(19) Check the electrical connection at the power
steering pressure switch on the power steering gear
housing (Fig. 24).
Fig. 17 Starter Motor and Ground Strap
Fig. 18 Knock Sensor
Fig. 19 Camshaft Position Sensor and Engine
Coolant Temperature Sensor
Fig. 20 Electronic EGR Transducer
Fig. 21 Generator
Fig. 22 Crankshaft Position Sensor
14 - 38 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DIAGNOSIS AND TESTING (Continued)

FUEL INJECTION SYSTEMÐ2.5L DIESEL ENGINE
INDEX
page page
GENERAL INFORMATION
INTRODUCTION....................... 43
DESCRIPTION AND OPERATION
AIR CONDITIONING (A/C) CONTROLSÐ
PCM INPUTS........................ 47
AIR CONDITIONING RELAYÐPCM OUTPUT . . 48
BATTERY VOLTAGEÐPCM INPUT.......... 45
BOOST PRESSURE SENSOR............. 45
BRAKE SWITCHÐPCM INPUT............. 47
DATA LINK CONNECTORÐ
PCM INPUT AND OUTPUT.............. 47
DIESEL PCM RELAYÐPCM INPUT......... 48
ENGINE COOLANT GAUGEÐPCM OUTPUT . . 48
ENGINE COOLANT TEMPERATURE SENSORÐ
PCM INPUT......................... 46
ENGINE OIL PRESSURE GAUGEÐ
PCM OUTPUT........................ 48
ENGINE SPEED SENSORÐPCM INPUT..... 46
EXHAUST GAS RECIRCULATION (EGR)
SOLENOIDÐPCM OUTPUT............. 50
FIVE VOLT POWERÐPCM OUTPUT........ 48
FUEL INJECTOR SENSORÐGROUND...... 46
FUEL TIMING SOLENOIDÐPCM OUTPUT.... 48
GLOW PLUG LAMPÐPCM OUTPUT........ 48
GLOW PLUG RELAYÐPCM OUTPUT....... 49
GLOW PLUGS......................... 49
IGNITION CIRCUIT SENSEÐPCM INPUT.... 45
NEEDLE MOVEMENT OR INSTRUMENTED
FIRST INJECTORÐPCM INPUT.......... 45
POWER GROUND...................... 45
POWERTRAIN CONTROL MODULE (PCM) . . . 44
SENSOR RETURNÐPCM INPUT (ANALOG
GROUND)........................... 45SIGNAL GROUNDÐPCM INPUT........... 45
SPEED CONTROLÐPCM INPUTS.......... 48
SPEED CONTROLÐPCM OUTPUTS........ 48
START SIGNALÐPCM INPUT............. 45
TACHOMETERÐPCM OUTPUT............ 49
VEHICLE SPEED SENSORÐPCM INPUT.... 47
VEHICLE THEFT ALARM................. 45
DIAGNOSIS AND TESTING
BOOST PRESSURE SENSOR............. 53
DIAGNOSTIC TROUBLE CODES........... 53
DIESEL DIAGNOSTICS.................. 50
DIESEL PCM RELAY TEST............... 50
ENGINE COOLANT TEMPERATURE
SENSOR TEST....................... 50
ENGINE SPEED SENSOR TEST........... 50
GLOW PLUG RELAY TEST............... 51
GLOW PLUG TEST..................... 51
RELAYSÐOPERATION/TESTING........... 52
VEHICLE SPEED SENSOR TEST........... 53
REMOVAL AND INSTALLATION
A/C CLUTCH RELAY.................... 53
DIESEL PCM RELAY.................... 53
ENGINE COOLANT TEMPERATURE
SENSOR............................ 54
ENGINE SPEED SENSOR................ 53
GLOW PLUG RELAY.................... 55
GLOW PLUGS......................... 54
POWERTRAIN CONTROL MODULE (PCM) . . . 55
VEHICLE SPEED SENSOR............... 55
SPECIFICATIONS
GLOW PLUG CURRENT DRAW............ 56
TORQUE CHARTÐ2.5L DIESEL............ 57
GENERAL INFORMATION
INTRODUCTION
This section will cover components either regulated
or controlled by the Powertrain Control Module
(PCM). The fuel heater relay, fuel heater and fuel
gauge are not operated by the PCM. These compo-
nents are controlled by the ignition (key) switch. All
other fuel system electrical components necessary to
operate the engine are controlled or regulated by the
PCM. Refer to the following PCM description for
more information.
Certain fuel system component failures may cause
a no start, or prevent the engine from running. It is
important to know that the PCM has a featurewhere, if possible, it will ignore the failed sensor, set
a code related to the sensor, and operate the engine
in a ªLimp Homeº mode. When the PCM is operating
in a ªLimp Homeº mode, the Diesel Glow Plug lamp
on the instrument panel will be constantly illumi-
nated, and the engine will most likely have a notice-
able loss of performance. An example of this would be
an Accelerator Pedal Position Sensor failure, and in
that situation, the engine would run at a constant
1100 RPM, regardless of the actual position of the
pedal. This is the most extreme of the three ªLimp
Homeº modes.
In addition to indicating that the glow plugs are
hot enough to start combustion, the Glow Plug Lamp
is also used in the diagnosis of the PCM, and when
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 43

illuminated constantly, it usually indicates a problem
has been detected somewhere within the fuel system.
The DRBIII scan tool is the best method for commu-
nicating with the PCM to diagnose faults within the
system.
DESCRIPTION AND OPERATION
POWERTRAIN CONTROL MODULE (PCM)
The Powertrain Control Module (PCM) is mounted
in the center consule to a bracket located in front of
the Air Bag Module (Fig. 1).
The PCM is a pre±programmed, dual micro±proces-
sor digital computer. It will either directly operate or
partially regulate the:
²Speed Control
²Speed Control LED lamp
²Fuel Timing Solenoid
²Glow Plug Relay
²Glow Plugs
²EGR Solenoid
²Glow Plug Lamp
²Diesel PCM Relay
²Air Conditioning Operation
²Tachometer
²Exhaust Gas Recirculation (EGR) Solenoid
The PCM can adapt its programming to meet
changing operating conditions.
The PCM receives input signals from various
switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operationsthrough different system components. These compo-
nents are referred to asPCM Outputs.The sensors
and switches that provide inputs to the PCM are con-
sideredPCM Inputs.
PCM Inputs are:
²Air Conditioning Selection
²Theft Alarm
²Clutch Switch
²Diesel PCM Relay
²ISO-Protocol
²Control Sleeve
²Fuel Temperature
²Boost Pressure Sensor
²Accelerator Pedal Sensor
²EGR
²A/C Pressure
²Engine Coolant Temperature Sensor
²Low Idle Position Switch
²5 Volt Supply
²Vehicle Speed Sensor
²Sensor Return
²Glow Plug
²Engine Speed Sensor (rpm)
²Fuel Injector #1 Sensor
²Starter Signal
²Brake Switch
²Speed Control Switch Position
²Power Ground
²Signal Ground
²Ignition (key) Switch Sense
²Battery Voltage
²SCI Receive (DRB scan tool connection)
PCM Outputs:
After inputs are received by the PCM, certain sen-
sors, switches and components are controlled or reg-
ulated by the PCM. These are consideredPCM
Outputs.These outputs are for:
²A/C Clutch Relay (for A/C clutch operation)
²Speed Control LED
²Data Link Connectors (for DRB scan tool)
²Diesel PCM Relay
²Diesel PCM Sense
²Accelarator Pedal
²5 Volts Supply
²Glow Plug Relay
²Fan Relay
²Fuel Quantity
²Fuel Timing Solenoid
²Fuel Shut-Off Solenoid
²Engine Speed Sensor
²Glow Plug Lamp (malfunction indicator lamp)
²Exhaust Gas Recirculation (EGR) Solenoid
²Glow Plug Relay
²Tachometer
²SCI transmit (DRB scan tool connection)
Fig. 1 PCM Location
14 - 44 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
GENERAL INFORMATION (Continued)

BOOST PRESSURE SENSOR
The Boost Pressure Sensor is mounted to the top of
the intake manifold. (Fig. 2) It is a sensor that mea-
sures both manifold vacuum and turbo boost, and it
also contains an integrated intake air temperature
sensor. The Boost Pressure Sensor takes the place of
the Mass Air Flow (MAF). In the Intake Air Temper-
ature Sensor component, there is a ceramic element
that changes its resistance based on temperature.
The ceramic element is part of an electronic circuit
connected to the PCM, and has a voltage applied to
it. The ceramic element is exposed to the air inside
the intake. This air has a cooling effect on the
ceramic element, and its resistance changes. This
causes the voltage flowing through the intake air
temperature circuit to vary. The voltage signal pro-
duced by the Intake Air Temperature Sensor changes
inversely to the temperature, and is measured by the
PCM. As a general rule, when the temperature of the
air in the intake is high, the voltage signal produced
by the Intake Air Temperature Sensor is low. The
component of the Boost Pressure Sensor that mea-
sures manifold vacuum and turbo boost produces a
voltage signal that is proportional to the pressure in
the inake manifold. When the intake manifold pres-
sure is low, the voltage is low, and when the pressure
is high, the voltage is high. The PCM uses the volt-
age signals from the Boost Pressure Sensor, and the
Intake Air Temperature Sensor to determine the
amount of air flowing through the intake manifold.
VEHICLE THEFT ALARM
The PCM can learn if the vehicle has a Vehicle
Theft Alarm (VTA) system. Once it detects the vehi-
cle having VTA,the controller can ONLY BE
USED ON VEHICLES WITH VTA.If the PCM is put it on a vehicle without VTA the
Glow Plug Lamp will start to blink and the vehicle
will not start.
The PCM cannot be flashed to remove the VTA.
BATTERY VOLTAGEÐPCM INPUT
The battery voltage input provides power to the
PCM. It also informs the PCM what voltage level is
being supplied by the generator once the vehicle is
running.
The battery input also provides the voltage that is
needed to keep the PCM memory alive. The memory
stores Diagnostic Trouble Code (DTC) messages.
Trouble codes will still be stored even if the battary
voltage is lost.
SENSOR RETURNÐPCM INPUT (ANALOG
GROUND)
Sensor Return provides a low noise Analog ground
reference for all system sensors.
SIGNAL GROUNDÐPCM INPUT
Signal ground provides a low noise ground to the
data link connector.
IGNITION CIRCUIT SENSEÐPCM INPUT
The ignition circuit sense input signals the PCM
that the ignition (key) switch has been turned to the
ON position. This signal initiates the glow plug con-
trol routine to begin the ªpre±heatº cycle.
START SIGNALÐPCM INPUT
This input tells the PCM that the engine starter is
being operated. This in turn will start the glow plug
ªpost±heatº cycle.
POWER GROUND
Provides a common ground for power devices (sole-
noid and relay devices).
NEEDLE MOVEMENT OR INSTRUMENTED FIRST
INJECTORÐPCM INPUT
This input from the PCM supplies a constant 30
mA electrical current source for the first injector sen-
sor. It will vary the voltage to this sensor when it
senses a mechanical movement within the injector
needle (pintle) of the number±1 cylinder fuel injector.
When this voltage has been determined by the PCM,
it will then control an output to the fuel timing sole-
noid (the fuel timing solenoid is located on the fuel
injection pump). Also refer to Fuel Injection Pump for
additional information.
The first injector sensor is a magnetic (inductive)
type.
Fig. 2 Boost Pressure Sensor Location
NS/GSFUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINE 14 - 45
DESCRIPTION AND OPERATION (Continued)

The first injector sensor is used only on the fuel
injector for the number±1 cylinder (Fig. 3). It is not
used on the injectors for cylinders number 2, 3, or 4.
FUEL INJECTOR SENSORÐGROUND
Provides a low noise ground for the fuel injector
sensor only.
ENGINE COOLANT TEMPERATURE SENSORÐPCM
INPUT
The 0±5 volt input from this sensor tells the PCM
the temperature of the engine coolant. Based on the
voltage received at the PCM, it will then determine
operation of the fuel timing solenoid, glow plug relay,
electrical vacuum modulator (emission component)
and generator (charging system).
The sensor is located on the side of the #3 cylinder
head near the rear of fuel injection pump (Fig. 4).
ENGINE SPEED SENSORÐPCM INPUT
The engine speed sensor is mounted to the trans-
mission bellhousing at the left/rear side of the engine
block (Fig. 5).
The engine speed sensor produces its own output
signal. If this signal is not received the engine will
not start by the PCM.
The engine speed sensor input is used in conjunc-
tion with the first injector sensor to establish fuel
injection pump timing.
The flywheel has four notches at its outer edge
(Fig. 6). Each notch is spaced equally every 90É. The
notches cause a pulse to be generated when they
pass under the speed sensor (Fig. 6). These pulses
are the input to the PCM. The input from this sensor
determines crankshaft position (in degrees) by moni-
toring the notches.The sensor also generates an rpm signal to the
PCM. This signal is used as an input for the Diesel
relay for control of the generator field, vehicle speed
control, and instrument panel mounted tachometer.
If the engine speed sensor should fail, the system
is unable to compensate for the problem and the car
will stop.
Fig. 3 Fuel Injector Sensor
Fig. 4 Engine Coolant Temperature Sensor Location
Fig. 5 Engine Speed Sensor Location
14 - 46 FUEL SYSTEMÐ2.5L DIESEL ENGINE/2.0L GAS ENGINENS/GS
DESCRIPTION AND OPERATION (Continued)