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The Crankshaft Position (CKP) sensor is located at the right-rear side of the engine cylinder block (Fig. 12). It is positioned and bolted into a machined hole in the engine block. (1) Raise vehicle. (2) Disconnect CKP electrical connector at sensor
(Fig. 12).
(3) Remove CKP mounting bolt (Fig. 12). (4) Carefully twist sensor from cylinder block. (5) Remove sensor from vehicle. (6) Check condition of sensor o-ring.
FUEL INJECTION - GAS
14 - 30
CRANKSHAFT POSITION SENSOR (Continued)DR
(2) Disconnect crankshaft position sensor pigtail
harness from main wiring harness.
(3) Remove two sensor (recessed hex head) mount-
ing bolts (Fig. 13).
(4) Remove sensor from engine.
8.0L V–10
The crankshaft position sensor is located on the right-lower side of the cylinder block, forward of the right engine mount, just above the oil pan rail (Fig. 14).
Fig.12CKPREMOVAL/INSTALLATION-5.7LV-8
1 - CYLINDER BLOCK - RIGHT / REAR 2 - ELEC. CONNECTOR 3 - MOUNTING BOLT 4 - CKP SENSOR5.9L Gas
The sensor is bolted to the top of the cylinder block
near the rear of right cylinder head (Fig. 13).
Fig.14CKPSENSORLOCATION–8.0LV-10
1 - CRANKSHAFT POSITION SENSOR 2 - HOLE 3 - OIL FILTER 4 - PLASTIC TIE STRAP 5 - PIGTAIL HARNESS
(1) Raise and support vehicle. (2) Disconnect sensor pigtail harness from main
engine wiring harness.
(3) Remove sensor mounting bolt (Fig. 15). (4) Cut plastic tie strap (Fig. 14) securing sensor
pigtail harness to side of engine block.
(5) Carefully pry sensor from cylinder block in a
rocking action with two small screwdrivers.
(6) Remove sensor from vehicle. (7) Check condition of sensor o-ring (Fig. 16).
INSTALLATION
3.7L V-6
(1) Clean out machined hole in engine block. (2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into engine block with a slight
rocking and twisting action.
Fig.13CKPREMOVAL/INSTALLATION-5.9LV-8
1 - GROMMET 2 - MOUNTING BOLTS (2) 3 - CRANKSHAFT POSITION SENSOR 4 - RIGHT EXHAUST MANIFOLD 5 - TRANSMISSION BELL HOUSING(1) Raise vehicle.
DR CRANKSHAFT POSITION SENSOR (Continued)
FUEL INJECTION - GAS
14 - 31
CAUTION: Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. flush, damage to sensor mounting tang may result.
If sensor is not
(4) Install mounting bolt and tighten to 28 N·m
(21 ft. lbs.) torque.
(5) Connect electrical connector to sensor. (6) Lower vehicle.
5.7L V-8
o-ring.
(1) Clean out machined hole in engine block. (2) Apply a small amount of engine oil to sensor
(3) Install sensor into engine block with a slight
rocking and twisting action.
Fig.15CKPSENSORR/I–8.0LV-10
1 - CRANKSHAFT POSITION SENSOR 2 - MOUNTING BOLT 3 - SENSOR POSITIONED FLUSH TO CYLINDER BLOCK
CAUTION: Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. flush, damage to sensor mounting tang may result.
If sensor is not
(4) Install mounting bolt and tighten to 28 N·m
(21 ft. lbs.) torque.
(5) Connect electrical connector to sensor. (6) Lower vehicle.
5.9L V-8 Gas
(1) Position crankshaft position sensor to engine. (2) Install mounting bolts and tighten to 8 N·m (70
(3) Connect main harness electrical connector to
in. lbs.) torque.
sensor.
(4) Lower vehicle.
8.0L V-10
o-ring.
(1) Apply a small amount of engine oil to sensor
(2) Install sensor into cylinder block with a slight rocking action. Do not twist sensor into position as damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. flush, damage to sensor mounting tang may result.
If sensor is not
(3) Install mounting bolt and tighten to 8 N·m (70
in. lbs.) torque.
wiring harness
(4) Connect sensor pigtail harness to main engine
(5) Install new plastic tie strap (Fig. 14) to secure sensor pigtail harness to side of engine block. Thread tie strap through casting hole on cylinder block.
Fig.16SENSORO-RING–8.0LV-10
1 - CRANKSHAFT POSITION SENSOR O-RING 2 - ELECTRICAL CONNECTOR 3 - PIGTAIL HARNESS
CAUTION: Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. flush, damage to sensor mounting tang may result.
If sensor is not
(4) Install mounting bolt and tighten to 28 N·m
(21 ft. lbs.) torque.
(5) Connect electrical connector to sensor. (6) Lower vehicle.
4.7L V-8
o-ring.
(1) Clean out machined hole in engine block. (2) Apply a small amount of engine oil to sensor
(3) Install sensor into engine block with a slight
rocking and twisting action.
14 - 32
FUEL INJECTION - GAS
DR
FUEL INJECTOR DESCRIPTION
An individual fuel injector (Fig. 17) is used for each
individual cylinder.
Fig.17FUELINJECTOR
1 - FUEL INJECTOR 2 - NOZZLE 3 - TOP (FUEL ENTRY)
OPERATION
OPERATION - FUEL INJECTOR
The top (fuel entry) end of the injector (Fig. 17) is
attached into an opening on the fuel rail.
The fuel
injectors are electrical solenoids. The injector contains a pintle that closes off an orifice at the nozzle end. When electric current is supplied to the injector, the armature and needle move a short distance against a spring, allowing fuel to flow out the orifice. Because the fuel is under high pressure, a fine spray is developed in the shape of a pencil stream. The spraying action atomizes the fuel, add- ing it to the air entering the combustion chamber.
The nozzle (outlet) ends of the injectors are posi- tioned into openings in the intake manifold just above the intake valve ports of the cylinder head. The engine wiring harness connector for each fuel injector is equipped with an attached numerical tag (INJ 1, INJ 2 etc.). This is used to identify each fuel injector.
The injectors are energized individually in a sequen- tial order by the Powertrain Control Module (PCM). The PCM will adjust injector pulse width by switching the ground path to each individual injector on and off. Injector pulse width is the period of time that the injector is energized. The PCM will adjust injector pulse width based on various inputs it receives.
Battery voltage is supplied to the injectors through
The PCM determines injector pulse width based on
the ASD relay.
various inputs.
OPERATION - PCM OUTPUT
The nozzle ends of the injectors are positioned into openings in the intake manifold just above the intake valve ports of the cylinder head. The engine wiring harness connector for each fuel injector is equipped with an attached numerical tag (INJ 1, INJ 2 etc.). This is used to identify each fuel injector with its respective cylinder number.
The injectors are energized individually in a sequen- tial order by the Powertrain Control Module (PCM). The PCM will adjust injector pulse width by switching the ground path to each individual injector on and off. Injector pulse width is the period of time that the injector is energized. The PCM will adjust injector pulse width based on various inputs it receives.
Battery voltage (12 volts +) is supplied to the injec- tors through the ASD relay. The ASD relay will shut- down the 12 volt power source to the fuel injectors if the PCM senses the ignition is on, but the engine is not running. This occurs after the engine has not been running for approximately 1.8 seconds.
The PCM determines injector on-time (pulse width)
based on various inputs.
REMOVAL
(1) Remove fuel rail. Refer to Fuel Injector Rail
Removal.
fuel rail (Fig. 18).
(2) Disconnect clip(s) that retain fuel injector(s) to
Fig.18INJECTORRETAININGCLIP
1 - PLIERS 2 - INJECTOR CLIP 3 - FUEL INJECTOR - TYPICAL 4 - FUEL RAIL - TYPICAL
DR FUEL INJECTOR (Continued) INSTALLATION
FUEL INJECTION - GAS
14 - 33
(1) Install fuel injector(s) into fuel rail assembly
and install retaining clip(s).
(2) If same injector(s) is being reinstalled, install
new o-ring(s).
(3) Apply a small amount of clean engine oil to
each injector o-ring. This will aid in installation.
(4) Install fuel rail. Refer to Fuel Rail Installation. (5) Start engine and check for fuel leaks.
FUEL PUMP RELAY DESCRIPTION
The 5–pin, 12–volt, fuel pump relay is located in the Power Distribution Center (PDC). Refer to the label on the PDC cover for relay location.
OPERATION
The Powertrain Control Module (PCM) energizes the electric fuel pump through the fuel pump relay. The fuel pump relay is energized by first applying battery voltage to it when the ignition key is turned ON, and then applying a ground signal to the relay from the PCM.
Whenever the ignition key is turned ON, the elec- tric fuel pump will operate. But, the PCM will shut- down the ground circuit to the fuel pump relay in approximately 1–3 seconds unless the engine is oper- ating or the starter motor is engaged.
REMOVAL
The fuel pump relay is located in the Power Distri- bution Center (PDC) (Fig. 19). Refer to label on PDC cover for relay location.
(1) Remove PDC cover. (2) Remove relay from PDC. (3) Check condition of relay terminals and PDC connector terminals for damage or corrosion. Repair if necessary before installing relay.
(4) Check for pin height (pin height should be the same for all terminals within the PDC connector). Repair if necessary before installing relay.
INSTALLATION
The fuel pump relay is located in the Power Distri- bution Center (PDC). Refer to label on PDC cover for relay location.
(1) Install relay to PDC. (2) Install cover to PDC.
Fig.19PDCLOCATION
1 - BATTERY 2 - PDC (POWER DISTRIBUTION CENTER)
IDLE AIR CONTROL MOTOR DESCRIPTION
A separate IAC motor is not used with the 5.7L V-8
engine.
The IAC stepper motor is mounted to the throttle body, and regulates the amount of air bypassing the control of the throttle plate. As engine loads and ambient temperatures change, engine rpm changes. A pintle on the IAC stepper motor protrudes into a passage in the throttle body, controlling air flow through the passage. The IAC is controlled by the Powertrain Control Module (PCM) to maintain the target engine idle speed.
OPERATION
engine.
A separate IAC motor is not used with the 5.7L V-8
At idle, engine speed can be increased by retract- ing the IAC motor pintle and allowing more air to pass through the port, or it can be decreased by restricting the passage with the pintle and diminish- ing the amount of air bypassing the throttle plate.
The IAC is called a stepper motor because it is moved (rotated) in steps, or increments. Opening the IAC opens an air passage around the throttle blade which increases RPM.
The PCM uses the IAC motor to control idle speed (along with timing) and to reach a desired MAP dur- ing decel (keep engine from stalling).
FUEL INJECTION - GAS
14 - 34
IDLE AIR CONTROL MOTOR (Continued)DR
The IAC motor has 4 wires with 4 circuits. Two of the wires are for 12 volts and ground to supply elec- trical current to the motor windings to operate the stepper motor in one direction. The other 2 wires are also for 12 volts and ground to supply electrical cur- rent to operate the stepper motor in the opposite direction.
To make the IAC go in the opposite direction, the PCM just reverses polarity on both windings. If only 1 wire is open, the IAC can only be moved 1 step (increment) in either direction. To keep the IAC motor in position when no movement is needed, the PCM will energize both windings at the same time. This locks the IAC motor in place.
In the IAC motor system, the PCM will count every step that the motor is moved. This allows the PCM to determine the motor pintle position. If the memory is cleared, the PCM no longer knows the position of the pintle. So at the first key ON, the PCM drives the IAC motor closed, regardless of where it was before. This zeros the counter. From this point the PCM will back out the IAC motor and keep track of its position again.
used for the following:
but idle speed will not stop quickly)
When engine rpm is above idle speed, the IAC is † Off-idle dashpot (throttle blade will close quickly † Deceleration air flow control † A/C compressor load control (also opens the pas- sage slightly before the compressor is engaged so that the engine rpm does not dip down when the compressor engages)
† Power steering load control The PCM can control polarity of the circuit to con-
trol direction of the stepper motor.
IAC Stepper Motor Program: The PCM is also equipped with a memory program that records the number of steps the IAC stepper motor most recently advanced to during a certain set of parameters. For example: The PCM was attempting to maintain a 1000 rpm target during a cold start-up cycle. The last recorded number of steps for that may have been 125. That value would be recorded in the memory cell so that the next time the PCM recognizes the identical conditions, the PCM recalls that 125 steps were required to maintain the target. This program allows for greater customer satisfaction due to greater control of engine idle.
Another function of the memory program, which occurs when the power steering switch (if equipped), or the A/C request circuit, requires that the IAC step- per motor control engine rpm, is the recording of the last targeted steps into the memory cell. The PCM can anticipate A/C compressor loads. This is accom- plished by delaying compressor operation for approx- imately 0.5 seconds until the PCM moves the IAC
stepper motor to the recorded steps that were loaded into the memory cell. Using this program helps elim- inate idle-quality changes as loads change. Finally, the PCM incorporates a 9No-Load9 engine speed lim- iter of approximately 1800 - 2000 rpm, when it rec- ognizes that the TPS is indicating an idle signal and IAC motor cannot maintain engine idle.
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the IAC motor through the PCM.
REMOVAL
3.7L V-6
The Idle Air Control (IAC) motor is located on the
side of the throttle body (Fig. 20).
(1) Remove air resonator box at throttle body. (2) Disconnect electrical connector from IAC motor. (3) Remove two mounting bolts (screws). (4) Remove IAC motor from throttle body.
Fig.20IDLEAIRCONTROLMOTOR-3.7LV-6
1 - THROTTLE POSITION SENSOR (TPS) 2 - MOUNTING SCREWS 3 - IDLE AIR CONTROL MOTOR (IAC) 4 - MOUNTING SCREWS
4.7L V-8
The Idle Air Control (IAC) motor is located on the
side of the throttle body (Fig. 21).
(1) Remove air resonator box at throttle body. (2) Disconnect electrical connector from IAC motor. (3) Remove two mounting bolts (screws). (4) Remove IAC motor from throttle body.
DR IDLE AIR CONTROL MOTOR (Continued)
FUEL INJECTION - GAS
14 - 35
Fig.22IDLEAIRCONTROLMOTOR-5.9LV-8
1 - MOUNTING SCREWS 2 - IDLE AIR CONTROL MOTOR
Fig.23IACMOTOR-8.0LV-10
1 - IDLE AIR CONTROL MOTOR 2 - INTAKE MANIFOLD (UPPER HALF) 3 - THROTTLE POSITION SENSOR 4 - THROTTLE BODY
INSTALLATION
3.7L V-6
The Idle Air Control (IAC) motor is located on the
side of the throttle body (Fig. 20).
(1) Install IAC motor to throttle body. (2) Install and tighten two mounting bolts (screws)
to 7 N·m (60 in. lbs.) torque.
(3) Install electrical connector. (4) Install air resonator to throttle body.
4.7L V-8
The Idle Air Control (IAC) motor is located on the
side of the throttle body (Fig. 21).
(1) Install IAC motor to throttle body.
Fig.21IDLEAIRCONTROLMOTOR-4.7LV-8
1 - THROTTLE BODY 2 - TPS 3 - IAC MOTOR 4 - IAT SENSOR 5 - MOUNTING SCREWS
5.7L V-8
The IAC motor is not serviceable on the 5.7L V-8
engine.
5.9L V-8
The IAC motor is located on the back of the throt-
tle body (Fig. 22).
(1) Remove air resonator box at throttle body. (2) Disconnect electrical connector from IAC motor. (3) Remove two mounting bolts (screws) (Fig. 22). (4) Remove IAC motor from throttle body.
8.0L V-10
tle body (Fig. 23).
The IAC motor is located on the back of the throt-
(1) Remove the air cleaner cover. (2) Remove the 4 air cleaner housing mounting
nuts and remove housing from throttle body.
(3) Disconnect electrical connector from IAC motor. (4) Remove two mounting bolts (screw). (5) Remove IAC motor from throttle body.
FUEL INJECTION - GAS
14 - 36
IDLE AIR CONTROL MOTOR (Continued)(2) Install and tighten two mounting bolts (screws)
to 7 N·m (60 in. lbs.) torque.
(3) Install electrical connector. (4) Install air resonator to throttle body.
5.7L V-8
The IAC motor is not serviceable on the 5.7L V-8
engine.
5.9L V-8
The IAC motor is located on the back of the throt-
tle body (Fig. 22).
(1) Install IAC motor to throttle body. (2) Install and tighten two mounting bolts (screws)
sor.
to 7 N·m (60 in. lbs.) torque.
(3) Install electrical connector. (4) Install air resonator to throttle body.
DR
† Adjustment of spark timing (to help prevent spark knock with high intake manifold air-charge temperatures)
The resistance values of the IAT sensor is the same as for the Engine Coolant Temperature (ECT) sensor.
REMOVAL
3.7L V-6
The intake manifold air temperature (IAT) sensor is installed into the left side of intake manifold ple- num (Fig. 24).
(1) Disconnect electrical connector from IAT sen-
(2) Clean dirt from intake manifold at sensor base. (3) Gently lift on small plastic release tab (Fig. 24) or (Fig. 25) and rotate sensor about 1/4 turn counter- clockwise for removal.
(4) Check condition of sensor o-ring.
8.0L V-10
tle body (Fig. 23).
The IAC motor is located on the back of the throt-
(1) Install IAC motor to throttle body. (2) Install and tighten two mounting bolts (screws)
to 7 N·m (60 in. lbs.) torque.
(3) Install electrical connector. (4) Install air cleaner housing to throttle body. (5) Install 4 air cleaner housing mounting nuts.
Tighten nuts to 11 N·m (96 in. lbs.) torque.
(6) Install air cleaner housing cover.
INTAKE AIR TEMPERATURE SENSOR DESCRIPTION
The 2–wire Intake Manifold Air Temperature (IAT) sensor is installed in the intake manifold with the sensor element extending into the air stream.
The IAT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as intake mani- fold temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resis- tance (voltage) in the sensor increases.
OPERATION
The IAT sensor provides an input voltage to the Powertrain Control Module (PCM) indicating the density of the air entering the intake manifold based upon intake manifold temperature. At key-on, a 5–volt power circuit is supplied to the sensor from the PCM. The sensor is grounded at the PCM through a low-noise, sensor-return circuit.
The PCM uses this input to calculate the following: † Injector pulse-width
Fig.24IATSENSORLOCATION-3.7LV-6
1 - IAT SENSOR 2 - RELEASE TAB 3 - ELECTRICAL CONNECTOR
4.7L V-8
The intake manifold air temperature (IAT) sensor is installed into the left side of intake manifold ple- num (Fig. 26).
(1) Disconnect electrical connector from IAT sen-
sor.
(2) Clean dirt from intake manifold at sensor base. (3) Gently lift on small plastic release tab (Fig. 25) or (Fig. 26) and rotate sensor about 1/4 turn counter- clockwise for removal.
DR INTAKE AIR TEMPERATURE SENSOR (Continued)
FUEL INJECTION - GAS
14 - 37
5.7L V-8
The intake manifold air temperature (IAT) sensor is installed into the front of the intake manifold air box plenum (Fig. 27).
(1) Disconnect electrical connector from IAT sensor
(Fig. 27).
(2) Clean dirt from intake manifold at sensor base. (3) Gently lift on small plastic release tab (Fig. 25) or (Fig. 28) and rotate sensor about 1/4 turn counter- clockwise for removal.
(4) Check condition of sensor o-ring.
Fig.25IATSENSORTAB/O-RING-3.7LV-6/4.7L
V-8/5.7LV-8
1 - IAT SENSOR 2 - SENSOR O-RING 3 - RELEASE TAB
(4) Check condition of sensor o-ring.
Fig.275.7LIATSENSORLOCATION
1 - FRONT OF INTAKE MANIFOLD PLENUM 2 - IAT ELECTRICAL CONNECTOR
5.9L
The intake manifold air temperature sensor is located in the front/side of the intake manifold (Fig. 29).
(1) Clean dirt from intake manifold at sensor base. (2) Disconnect electrical connector at sensor (Fig.
29).
(3) Remove sensor from intake manifold.
Fig.26IATSENSOR-4.7LV-8
1 - LEFT SIDE OF THROTTLE BODY 2 - ELEC. CONNECT. 3 - IAT SENSOR 4 - RELEASE TAB
8.0L V-10
The intake manifold air temperature sensor is located in the side of the intake manifold near the front of throttle body (Fig. 30).
(1) Disconnect electrical connector at sensor. (2) Remove sensor from intake manifold.
FUEL INJECTION - GAS
14 - 38
INTAKE AIR TEMPERATURE SENSOR (Continued)DR
Fig.30AIRTEMPERATURESENSOR-8.0LV-10
1 - INTAKE MANIFOLD AIR TEMP. SENSOR 2 - INTAKE MANIFOLD
Fig.285.7LIATSENSORR/I
1 - FRONT OF INTAKE MANIFOLD PLENUM 2 - IAT SENSOR 3 - RELEASE TAB
Fig.29IATSENSORLOCATION-5.9L
1 - INTAKE MANIFOLD AIR TEMPERATURE SENSOR 2 - ELECTRICAL CONNECTOR
INSTALLATION
3.7L V-6
(2) Clean sensor mounting hole in intake manifold. (3) Position sensor into intake manifold and rotate
clockwise until past release tab (Fig. 24).
(4) Install electrical connector.
4.7L V-8
The intake manifold air temperature (IAT) sensor is installed into the left side of intake manifold ple- num (Fig. 26).
(1) Check condition of sensor o-ring. (2) Clean sensor mounting hole in intake manifold. (3) Position sensor into intake manifold and rotate
clockwise until past release tab. (4) Install electrical connector.
5.7L V-8
The intake manifold air temperature (IAT) sensor is installed into the front of the intake manifold air box plenum (Fig. 27).
(1) Check condition of sensor o-ring. (2) Clean sensor mounting hole in intake manifold. (3) Position sensor into intake manifold and rotate
clockwise until past release tab. (4) Install electrical connector.
5.9L V-8
The intake manifold air temperature sensor is located in the front/side of the intake manifold (Fig. 29).
(1) Install sensor to intake manifold. Tighten to
12–15 N·m (110–130 in. lbs.) torque.
(2) Install electrical connector.
The intake manifold air temperature (IAT) sensor is installed into the left side of intake manifold ple- num (Fig. 24).
(1) Check condition of sensor o-ring.
8.0L V-10
The intake manifold air temperature sensor is located in the side of the intake manifold near the front of throttle body (Fig. 30).
DR INTAKE AIR TEMPERATURE SENSOR (Continued)
FUEL INJECTION - GAS
14 - 39
(1) Install sensor to intake manifold. Tighten to
12–15 N·m (110–130 in. lbs.) torque.
(2) Install electrical connector.
MAP SENSOR DESCRIPTION
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is mounted into the front of the intake manifold with 2
screws.4.7L V-8
The Manifold Absolute Pressure (MAP) sensor is mounted into the front of the intake manifold with 2
screws.5.7L V-8
The Manifold Absolute Pressure (MAP) sensor is mounted to the front of the intake manifold air ple- num box.
5.9L V-8
The Manifold Absolute Pressure (MAP) sensor is mounted to the front of the throttle body with 2
screws.8.0L V-10
The Manifold Absolute Pressure (MAP) sensor is
mounted into the right side of the intake manifold.
OPERATION
The MAP sensor is used as an input to the Power- train Control Module (PCM). It contains a silicon based sensing unit to provide data on the manifold vacuum that draws the air/fuel mixture into the com- bustion chamber. The PCM requires this information to determine injector pulse width and spark advance. When manifold absolute pressure (MAP) equals Barometric pressure, the pulse width will be at max- imum.
A 5 volt reference is supplied from the PCM and returns a voltage signal to the PCM that reflects manifold pressure. The zero pressure reading is 0.5V and full scale is 4.5V. For a pressure swing of 0–15
psi, the voltage changes 4.0V. To operate the sensor, it is supplied a regulated 4.8 to 5.1 volts. Ground is provided through the low-noise, sensor return circuit at the PCM.The MAP sensor input is the number one contrib- utor to fuel injector pulse width. The most important function of the MAP sensor is to determine baromet- ric pressure. The PCM needs to know if the vehicle is at sea level or at a higher altitude, because the air
density changes with altitude. It will also help to cor- rect for varying barometric pressure. Barometric pressure and altitude have a direct inverse correla- tion; as altitude goes up, barometric goes down. At key-on, the PCM powers up and looks at MAP volt- age, and based upon the voltage it sees, it knows the current barometric pressure (relative to altitude). Once the engine starts, the PCM looks at the voltage again, continuously every 12 milliseconds, and com- pares the current voltage to what it was at key-on. The difference between current voltage and what it was at key-on, is manifold vacuum.
During key-on (engine not running) the sensor reads (updates) barometric pressure. A normal range can be obtained by monitoring a known good sensor. As the altitude increases, the air becomes thinner (less oxygen). If a vehicle is started and driven to a very different altitude than where it was at key-on, the barometric pressure needs to be updated. Any time the PCM sees Wide Open Throttle (WOT), based upon Throttle Position Sensor (TPS) angle and RPM, it will update barometric pressure in the MAP mem- ory cell. With periodic updates, the PCM can make its calculations more effectively.
The PCM uses the MAP sensor input to aid in cal- culating the following: † Manifold pressure † Barometric pressure † Engine load † Injector pulse-width † Spark-advance programs † Shift-point strategies (certain automatic trans- missions only) † Idle speed † Decel fuel shutoff The MAP sensor signal is provided from a single piezoresistive element located in the center of a dia- phragm. The element and diaphragm are both made of silicone. As manifold pressure changes, the dia- phragm moves causing the element to deflect, which stresses the silicone. When silicone is exposed to stress, its resistance changes. As manifold vacuum increases, the MAP sensor input voltage decreases proportionally. The sensor also contains electronics that condition the signal and provide temperature compensation.
The PCM recognizes a decrease in manifold pres- sure by monitoring a decrease in voltage from the reading stored in the barometric pressure memory cell. The MAP sensor is a linear sensor; meaning as pressure changes, voltage changes proportionately. The range of voltage output from the sensor is usu- ally between 4.6 volts at sea level to as low as 0.3
volts at 26 in. of Hg. Barometric pressure is the pres- sure exerted by the atmosphere upon an object. At sea level on a standard day, no storm, barometricDR
FUEL INJECTION - GAS
14 - 40
MAP SENSOR (Continued)pressure is approximately 29.92 in Hg. For every 100
feet of altitude, barometric pressure drops 0.10 in. Hg. If a storm goes through, it can change baromet- ric pressure from what should be present for that altitude. You should know what the average pressure and corresponding barometric pressure is for your area.REMOVAL
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is mounted into the front of the intake manifold (Fig. 31). An o-ring is used to seal the sensor to the intake manifold (Fig. 32).
(1) Disconnect electrical connector at sensor. (2) Clean area around MAP sensor. (3) Remove 2 sensor mounting screws. (4) Remove MAP sensor from intake manifold. (5) Check condition of sensor o-ring (Fig. 32).
Fig.32MAPSENSORO-RING3.7L/4.7L
1 - MAP SENSOR 2 - O-RING
(5) Check condition of sensor o-ring (Fig. 32).
Fig.31MAPSENSOR-3.7LV-6
1 - MOUNTING SCREWS 2 - MAP SENSOR 3 - ECT SENSOR 4 - FRONT OF INTAKE MANIFOLD
4.7L V-8
The MAP sensor is located on the front of the intake manifold (Fig. 33). An o-ring seals the sensor to the intake manifold.
(1) Disconnect electrical connector at sensor. (2) Clean area around MAP sensor. (3) Remove 2 sensor mounting bolts (Fig. 33). (4) Remove MAP sensor from intake manifold.
Fig.33MAPSENSOR-4.7LV-8
1 - ECT SENSOR 2 - MOUNTING BOLTS (2) 3 - MAP SENSOR 4 - INTAKE MANIFOLD
DR MAP SENSOR (Continued) 5.7L V-8
FUEL INJECTION - GAS
14 - 41
The Manifold Absolute Pressure (MAP) sensor is mounted to the front of the intake manifold air ple- num box (Fig. 34).
(1) Disconnect electrical connector at sensor by sliding release lock out (Fig. 35). Press down on lock tab for removal.
(2) Rotate sensor 1/4 turn counter-clockwise for
removal.
(3) Check condition of sensor o-ring.
Fig.355.7LMAPSENSORR/I
1 - PRESS DOWN 2 - SLIDE RELEASE LOCK 3 - MAP SENSOR
Fig.36MAPSENSOR-5.9LV-8
1 - MAP SENSOR 2 - MOUNTING SCREWS (2)
(1) Remove electrical connector at sensor. (2) Clean area around sensor before removal. (3) Remove two sensor mounting bolts. (4) Remove sensor from intake manifold.
Fig.345.7LMAPSENSORLOCATION
1 - MAP SENSOR 2 - FRONT OF INTAKE MANIFOLD
5.9L V-8
The MAP sensor is located on the front of the throttle body (Fig. 36). An L-shaped rubber fitting is used to connect the MAP sensor to throttle body (Fig. 37).
(1) Clean area around MAP sensor. (2) Remove
two MAP sensor mounting bolts
(screws) (Fig. 36).
(3) While removing MAP sensor, slide the vacuum rubber L-shaped fitting (Fig. 37) from the throttle body.
(4) Remove rubber L-shaped fitting from MAP sen-
sor.
8.0L V-10
The MAP sensor is mounted into the right upper side of intake manifold (Fig. 38). A rubber gasket is used to seal sensor to intake manifold. The rubber gasket is part of sensor and is not serviced sepa- rately.
FUEL INJECTION - GAS
14 - 42
MAP SENSOR (Continued)DR
(4) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(5) Connect electrical connector.
4.7L V-8
The MAP sensor is located on the front of the intake manifold (Fig. 33). An o-ring seals the sensor to the intake manifold (Fig. 32).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears. (3) Position sensor into manifold. (4) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(5) Connect electrical connector.
Fig.37MAPSENSORL-SHAPEDRUBBERFITTING
-5.9LV-8
1 - MAP SENSOR 2 - RUBBER FITTING 3 - IDLE AIR PASSAGE
Fig.38MAPSENSORLOCATION-8.0LV-10
1 - MAP SENSOR 2 - MOUNTING BOLTS 3 - THROTTLE BODY
INSTALLATION
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is mounted into the front of the intake manifold (Fig. 31). An o-ring is used to seal the sensor to the intake manifold (Fig. 32).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears. (3) Position sensor into manifold.
5.7L V-8
manifold.
The Manifold Absolute Pressure (MAP) sensor is mounted to the front of the intake manifold air ple- num box (Fig. 34).
(1) Clean MAP sensor mounting hole at intake
(2) Check MAP sensor o-ring seal for cuts or tears. (3) Position sensor into manifold. (4) Rotate sensor 1/4 turn clockwise for installa-
tion.
(5) Connect electrical connector.
5.9L V-8
The MAP sensor is located on the front of the throttle body (Fig. 36). An L-shaped rubber fitting is used to connect the MAP sensor to throttle body (Fig. 37).
(1) Install rubber L-shaped fitting to MAP sensor. (2) Position sensor to throttle body while guiding
rubber fitting over throttle body vacuum nipple.
(3) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications. (4) Install air resonator box.
8.0L V-10
The MAP sensor is mounted into the right upper side of intake manifold (Fig. 38). A rubber gasket is used to seal sensor to intake manifold. The rubber gasket is part of sensor and is not serviced sepa- rately.
(1) Check condition of sensor seal. Clean sensor
and lubricate rubber gasket with clean engine oil.
(2) Clean sensor opening in intake manifold. (3) Install sensor into intake manifold. (4) Install sensor mounting bolts. Refer to Torque
Specifications.
(5) Install electrical connector to sensor.
DR
FUEL INJECTION - GAS
14 - 43
OXYGEN SENSOR DESCRIPTION
The Oxygen Sensors (O2S) are attached to, and protrude into the vehicle exhaust system. Depending on the engine or emission package, the vehicle may use a total of either 2 or 4 sensors.
Federal Emission Packages : Two sensors are used: upstream (referred to as 1/1) and downstream (referred to as 1/2). With this emission package, the upstream sensor (1/1) is located just before the main catalytic convertor. The downstream sensor (1/2) is located just after the main catalytic convertor.
California Emission Packages: On this emis- sions package, 4 sensors are used: 2 upstream (referred to as 1/1 and 2/1) and 2 downstream (referred to as 1/2 and 2/2). With this emission pack- age, the right upstream sensor (2/1) is located in the right exhaust downpipe just before the mini-catalytic convertor. The left upstream sensor (1/1) is located in the left exhaust downpipe just before the mini-cata- lytic convertor. The right downstream sensor (2/2) is located in the right exhaust downpipe just after the mini-catalytic convertor, and before the main cata- lytic convertor. The left downstream sensor (1/2) is located in the left exhaust downpipe just after the mini-catalytic convertor, and before the main cata- lytic convertor.
OPERATION
An O2 sensor is a galvanic battery that provides the PCM with a voltage signal (0-1 volt) inversely proportional to the amount of oxygen in the exhaust. In other words, if the oxygen content is low, the volt- age output is high; if the oxygen content is high the output voltage is low. The PCM uses this information to adjust the 14.7–to–1 air/fuel ratio necessary for proper engine operation and to control emissions.
injector pulse-width to achieve
The O2 sensor must have a source of oxygen from outside of the exhaust stream for comparison. Cur- rent O2 sensors receive their fresh oxygen (outside air) supply through the O2 sensor case housing.
Four wires (circuits) are used on each O2 sensor: a 12–volt feed circuit for the sensor heating element; a ground circuit for the heater element; a low-noise sensor return circuit to the PCM, and an input cir- cuit from the sensor back to the PCM to detect sen- sor operation.
Oxygen Sensor Heater Relay - 5.9L/8.0L: If 4
oxygen sensors are used, a separate heater relay is used to supply voltage to the sensors heating ele- ments for only the 1/2 and 2/2 downstream sensors. Voltage for the other 2 sensor heating elements is supplied directly from the Powertrain Control Mod-ule (PCM) through a Pulse Width Module (PWM) method.
Pulse Width Module (PWM) - 5.9L/8.0L: Voltage to the O2 sensor heating elements is supplied directly from the Powertrain Control Module (PCM) through two separate Pulse Width Module (PWM) low side drivers. PWM is used on both the upstream and downstream O2 sensors if equipped with a Fed- eral Emissions Package, and only on the 2 upstream sensors (1/1 and 2/1) if equipped with a California Emissions Package. The main objective for a PWM driver is to avoid overheating of the O2 sensor heater element. With exhaust temperatures increasing with time and engine speed, it’s not required to have a full-voltage duty-cycle on the O2 heater elements.
To avoid the large simultaneous current surge needed to operate all 4 sensors, power is delayed to the 2 downstream heater elements by the PCM for approximately 2 seconds.
ambient
increases. At
Oxygen Sensor Heater Elements: The O2 sensor uses a Positive Thermal Co-efficient (PTC) heater element. As temperature increases, resistance temperatures around 70°F, the resistance of the heating element is approximately 13 ohms. As the sensor’s temperature increases, resistance in the heater element increases. This allows the heater to maintain the optimum operating temperature of approximately 930°-1100°F (500°-600° C). Although the sensors operate the same, there are physical differences, due to the envi- ronment that they operate in, that keep them from being interchangeable.
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 cer- tain O2 sensor input(s) 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 preprogrammed (fixed) values and inputs from other sensors.
Upstream Sensor - Federal Emissions Pack- age : The upstream sensor (1/1) provides an input voltage to the PCM. The input tells the PCM the oxy- gen content of the exhaust gas. The PCM uses this information to fine tune fuel delivery to maintain the correct oxygen content at the downstream oxygen sensor. The PCM will change the air/fuel ratio until the upstream sensor inputs a voltage that the PCM has determined will make the downstream sensor output (oxygen content) correct.
The upstream oxygen sensor also provides an input
to determine catalytic convertor efficiency.
DR
Refer to (Fig. 39) or (Fig. 40) for typical O2S (oxy-
gen sensor) locations.
WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES AND CATALYTIC CONVERTER BECOME VERY HOT DURING ENGINE OPERATION. ALLOW ENGINE TO COOL BEFORE REMOVING OXYGEN SENSOR.
(1) Raise and support vehicle. (2) Disconnect wire connector from O2S sensor.
CAUTION: When disconnecting sensor electrical connector, do not pull directly on wire going into sensor.
(3) Remove O2S sensor with an oxygen sensor
removal and installation tool.
(4) Clean threads in exhaust pipe using appropri-
ate tap.
Fig.39O2SENSORSYSTEM-WITH4SENSORS
FUEL INJECTION - GAS
14 - 44
OXYGEN SENSOR (Continued)Downstream Sensor
- Federal Emissions Package : The downstream oxygen sensor (1/2) is also used to determine the correct air-fuel ratio. As the oxygen content changes at the downstream sen- sor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor voltage and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor voltage (oxygen content).
The downstream oxygen sensor also provides an
input to determine catalytic convertor efficiency.
Upstream Sensors
- California Emissions Package : Two upstream sensors are used (1/1 and 2/1). The 1/1 sensor is the first sensor to receive exhaust gases from the #1 cylinder. They provide an input voltage to the PCM. The input tells the PCM the oxygen content of the exhaust gas. The PCM uses this information to fine tune fuel delivery to main- tain the correct oxygen content at the downstream oxygen sensors. The PCM will change the air/fuel ratio until the upstream sensors input a voltage that the PCM has determined will make the downstream sensors output (oxygen content) correct.
The upstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not calculated with this pack- age.
Downstream Sensors - California Emissions Package : Two downstream sensors are used (1/2
and 2/2). The downstream sensors are used to deter- mine the correct air-fuel ratio. As the oxygen content changes at the downstream sensor, the PCM calcu- lates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor volt- age, and changes fuel delivery until the upstream sensor voltage changes enough to correct the down- stream sensor voltage (oxygen content).The downstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main cat- alytic convertor efficiency is not calculated with this package.
convertor efficiency.
Engines equipped with either a downstream sen- sor(s), or a post-catalytic sensor, will monitor cata- lytic If efficiency is below emission standards, the Malfunction Indicator Lamp (MIL) will be illuminated and a Diagnostic Trouble Code (DTC) will be set. Refer to Monitored Systems in Emission Control Systems for additional informa- tion.
REMOVAL
CAUTION: Never apply any type of grease to the oxygen sensor electrical connector, or attempt any soldering of the sensor wiring harness.
Fig.40O2SENSORSYSTEM-WITH2SENSORS 1 - POST CATALYST OXYGEN SENSOR (1/3) 2 - PRE-CATALYST OXYGEN SENSOR (1/2)
DR OXYGEN SENSOR (Continued) INSTALLATION
Threads of new oxygen sensors are factory coated with anti-seize compound to aid in removal. DO NOT add any additional anti-seize compound to threads of a new oxygen sensor.
(1) Install O2S sensor. Tighten to 30 N·m (22 ft.
lbs.) torque.
(2) Connect O2S sensor wire connector. (3) Lower vehicle.
THROTTLE BODY DESCRIPTION
The throttle body is located on the intake manifold. Fuel does not enter the intake manifold through the throttle body. Fuel is sprayed into the manifold by the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake manifold through the throttle body. The throttle body contains an air control passage controlled by an Idle Air Control (IAC) motor. The air control passage is used to supply air for idle conditions. A throttle valve (plate) is used to supply air for above idle conditions.
5.7L V-8 Engine: The throttle body on the 5.7L engine is an electri- cally controlled unit. A mechanical cable is not used to connect the throttle body to the accelerator pedal. The Accelerator Pedal Position Sensor (APPS) along with inputs from other sensors sets the throttle blade to pre-determined positions. Except 5.7L V-8 Engine: Certain sensors are attached to the throttle body. The accelerator pedal cable, speed control cable and transmission control cable (when equipped) are con- nected to the throttle body linkage arm.
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the PCM.
REMOVAL
3.7L V-6
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the Powertrain Control Module (PCM).
(1) Remove air cleaner tube at throttle body. (2) Disconnect throttle body electrical connectors
at IAC motor and TPS.
FUEL INJECTION - GAS
14 - 45
(3) Remove all control cables from throttle body (lever) arm. Refer to the Accelerator Pedal and Throt- tle Cable section for removal/installation procedures. (4) Disconnect necessary vacuum lines at throttle
(5) Remove 3 throttle body mounting bolts (Fig.
body.
41).
(6) Remove throttle body from intake manifold. (7) Check condition of old throttle body-to-intake
manifold o-ring (Fig. 42).
Fig.41THROTTLEBODYMOUNTINGBOLTS-3.7L
V-6
1 - THROTTLE BODY 2 - MOUNTING BOLTS (3)
4.7L V-8
(1) Remove air duct and air resonator box at throt-
tle body.
(2) Disconnect throttle body electrical connectors
at IAC motor and TPS (Fig. 43).
(3) Remove vacuum line at throttle body. (4) Remove all control cables from throttle body (lever) arm. Refer to Accelerator Pedal and Throttle Cable.
(5) Remove three throttle body mounting bolts
(Fig. 43).
(6) Remove throttle body from intake manifold.
5.7L V-8
CAUTION: Do not use spray (carb) cleaners on any part of the throttle body. Do not apply silicone lubri- cants to any part of the throttle body.
FUEL INJECTION - GAS
14 - 46
THROTTLE BODY (Continued)DR
(5) Check condition of throttle body o-ring (Fig.
45).
(6) If the throttle body has been changed, the fol-
lowing procedure must be performed:
(a) Disconnect negative battery cable from bat- tery. Leave cable disconnected for approximately 90
seconds.(b) Reconnect cable to battery. (c) Turn ignition switch ON, but do not crank
engine.
(d) Leave ignition switch ON for a minimum of 10 seconds. This will allow PCM to learn throttle body electrical parameters.
Fig.42THROTTLEBODYO-RING-3.7LV-6
1 - INTAKE MANIFOLD 2 - THROTTLE BODY O-RING
Fig.43THROTTLEBODYMOUNTINGBOLTS-4.7L
V-8
1 - MOUNTING BOLTS (3) 2 - THROTTLE BODY 3 - IAT SENSOR CONNECTOR 4 - IAC MOTOR CONNECTOR 5 - TPS CONNECTOR
(1) Remove air duct and air resonator box at throt-
(2) Disconnect electrical connector at throttle body
(3) Remove 4 throttle body mounting bolts (Fig.
tle body.
(Fig. 44).
44).
(4) Remove throttle body from intake manifold.
Fig.445.7LV-8THROTTLEBODY
1 - THROTTLE BODY 2 - ELECTRICAL CONNECTOR 3 - SILICONE SEAL 4 - MOUNTING BOLTS (4)
5.9L V-8
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the powertrain control module (PCM).
(1) Remove the air cleaner resonator tube. (2) Disconnect throttle body electrical connectors
at MAP sensor, IAC motor and TPS (Fig. 46).
(3) Remove vacuum line at throttle body. (4) Remove all control cables from throttle body (lever) arm. Refer to the Accelerator Pedal and Throt- tle Cable section of this group for additional informa- tion.
DR THROTTLE BODY (Continued)
FUEL INJECTION - GAS
14 - 47
Fig.455.7LV-8THROTTLEBODYO-RING
1 - INTAKE MANIFOLD 2 - THROTTLE BODY O-RING
(5) Remove four throttle body mounting bolts (Fig.
(6) Remove throttle body from intake manifold. (7) Discard old throttle body-to-intake manifold
47).
gasket.
Fig.47THROTTLEBODYMOUNTINGBOLTS-5.9L
V-8
1 - THROTTLE BODY MOUNTING BOLTS (4) 2 - THROTTLE BODY
8.0L V-10
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the powertrain control module (PCM).
(1) Remove air plenum resonator. (2) Disconnect throttle body electrical connectors
at the IAC motor and TPS.
(3) Remove all control cables from throttle body (lever) arm. Refer to the Accelerator Pedal and Throt- tle Cable section of this group for additional informa- tion.
(4) Remove four throttle body mounting nuts (Fig.
(5) Remove throttle body from intake manifold. (6) Discard old throttle body-to-intake manifold
48).
gasket.
Fig.46SENSORELECTRICALCONNECTORS-5.9L
V-8
1 - MAP SENSOR 2 - IDLE AIR CONTROL MOTOR 3 - THROTTLE POSITION SENSOR
INSTALLATION
3.7L V-6
(1) Check condition of throttle body-to-intake man-
ifold o-ring. Replace as necessary.
(2) Clean mating surfaces of throttle body and
intake manifold.
(3) Install throttle body-to-intake manifold o-ring. (4) Install throttle body to intake manifold. (5) Install 3 mounting bolts. Tighten bolts to 12
N·m (105 in. lbs.) torque.
FUEL INJECTION - GAS
14 - 48
THROTTLE BODY (Continued)DR
(3) Install throttle body to intake manifold by posi-
tioning throttle body to manifold alignment pins.
(4) Install 4 mounting bolts. Refer to Torque Spec-
ifications.
(5) Install electrical connector. (6) Install air plenum. (7)
If the throttle body has been changed, the
following procedure must be performed:
(a) Disconnect negative battery cable from bat- tery. Leave cable disconnected for approximately 90
seconds.(b) Reconnect cable to battery. (c) Turn ignition switch ON, but do not crank
(d) Leave ignition switch ON for a minimum of 10 seconds. This will allow PCM to learn throttle body electrical parameters.
engine.
5.9L V-8
Fig.48THROTTLEBODYMOUNTINGNUTS-8.0L
V-10
1 - INTAKE MANIFOLD UPPER HALF 2 - GASKET 3 - THROTTLE BODY 4 - MOUNTING NUTS (4)(6) Install control cables. (7) Install electrical connectors. (8) Install necessary vacuum lines. (9) Install air plenum.
4.7L V-8
(1) Clean throttle body-to-intake manifold o-ring. (2) Clean mating surfaces of throttle body and
intake manifold.
(3) Install throttle body to intake manifold by posi-
tioning throttle body to manifold alignment pins.
(4) Install three mounting bolts. Tighten bolts to
12 N·m (105 in. lbs.) torque.
(5) Install control cables. (6) Install vacuum line to throttle body. (7) Install electrical connectors. (8) Install air plenum.
5.7L V-8
CAUTION: Do not use spray (carb) cleaners on any part of the throttle body. Do not apply silicone lubri- cants to any part of the throttle body.
(1) Clean and check condition of throttle body-to-
intake manifold o-ring.
intake manifold.
(2) Clean mating surfaces of throttle body and
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the powertrain control module (PCM). (1) Clean the mating surfaces of the throttle body
and the intake manifold.
(2) Install new throttle body-to-intake manifold
gasket.
(3) Install throttle body to intake manifold. (4) Install four mounting bolts. Tighten bolts to 23
N·m (200 in. lbs.) torque.
(5) Install control cables. (6) Install vacuum line to throttle body. (7) Install electrical connectors. (8) Install air plenum.
8.0L V-10
A (factory adjusted) set screw is used to mechani- cally limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the powertrain control module (PCM). (1) Clean mating surfaces of throttle body and
intake manifold.
gasket.
(2) Install new throttle body-to-intake manifold
(3) Install throttle body to intake manifold. (4) Install four mounting nuts (Fig. 48). Refer to
Torque Specifications.
(5) Install control cables. (6) Install electrical connectors. (7) Install air plenum and hoses.
DR
FUEL INJECTION - GAS
14 - 49
THROTTLE CONTROL CABLE REMOVAL
3.7L V-6
CAUTION: Be careful not to damage or kink cable core wire (within cable sheathing) while servicing accelerator pedal or throttle cable.
(1) From inside vehicle, hold up accelerator pedal. Remove plastic cable retainer (clip) and throttle cable core wire from upper end of pedal arm (Fig. 1). Plas- tic cable retainer snaps into top of pedal arm.
(2) Remove cable core wire at pedal arm. (3) From inside vehicle, remove metal clip holding
cable to dashpanel (Fig. 1).
(4) Remove air resonator box at throttle body. (5) Unsnap cable from dashpanel routing clip. (6) Remove cable housing from dash panel and
pull into engine compartment.
(7) Hold throttle in wide open position. While held in this position, slide throttle cable pin (Fig. 49) from throttle body bellcrank.
(8) Using a pick or small screwdriver, press release tab (Fig. 50) to release plastic cable mount from bracket. Press on tab only enough to release cable from bracket. If tab is pressed too much, it will be broken. Slide plastic mount (Fig. 50) towards right side of vehicle to remove throttle cable from throttle body bracket.
(9) Remove throttle cable from vehicle.
Fig.49THROTTLECABLEPIN-3.7LV-6
1 - THROTTLE CABLE PIN 2 - THROTTLE BODY BELLCRANK 3 - PUSH UP HERE
Fig.50THROTTLECABLERELEASETAB-3.7LV-6
1 - THROTTLE CABLE 2 - RELEASE TAB 3 - PICK OR SCREWDRIVER 4 - PLASTIC CABLE MOUNT4.7L V-8
CAUTION: Be careful not to damage or kink cable core wire (within cable sheathing) while servicing accelerator pedal or throttle cable.
(1) From inside vehicle, hold up accelerator pedal. Remove plastic cable retainer (clip) and throttle cable core wire from upper end of pedal arm (Fig. 1). Plas- tic cable retainer (clip) snaps into pedal arm.
(2) Remove cable core wire at pedal arm. (3) From inside vehicle, remove cable clip holding
cable to dashpanel (Fig. 1).
(4) Remove air box at throttle body. (5) Unsnap cable from dashpanel routing clip. (6) Remove cable housing from dash panel and
pull into engine compartment.
(7) Using finger pressure only, disconnect accelera- tor cable connector at throttle body bellcrank pin by pushing connector off bellcrank pin towards front of vehicle (Fig. 51). DO NOT try to pull connector off perpendicular to bellcrank pin. Connector will be broken.
(8) Lift accelerator cable from top of cable cam
(Fig. 51).
(9) Press tab (Fig. 52) to release plastic cable mount from bracket. Press on tab only enough to release cable from bracket. If tab is pressed too much, it will be broken. Slide plastic mount (Fig. 52) towards passenger side of vehicle to remove cable from bracket.
(10) Remove throttle cable from vehicle.
FUEL INJECTION - GAS
14 - 50
THROTTLE CONTROL CABLE (Continued)DR
Fig.51ACCELERATORCABLEATBELLCRANK-
4.7LV-8
1 - THROTTLE BODY 2 - SPEED CONTROL CABLE CONNECTOR 3 - OFF 4 - OFF 5 - ACCELERATOR CABLE CONNECTOR 6 - CABLE CAM 7 - BELLCRANK
5.7L V-8
The Throttle Control Cable on the 5.7L V-8 engine connects the accelerator pedal to the Accelerator Pedal Position Sensor (APPS). A separate mechanical cable is not routed to the throttle body.
CAUTION: Be careful not to damage or kink cable core wire (within cable sheathing) while servicing accelerator pedal, cables or APPS.
(1) From inside vehicle, hold up accelerator pedal. Remove plastic cable retainer and throttle cable core wire from upper end of pedal arm (Fig. 1). The plas- tic cable retainer snaps into pedal arm.
(2) Remove cable core wire at pedal arm. (3) Remove APPS. Refer to Accelerator Pedal Posi-
tion Sensor (APPS) Removal / Installation.
(4) From inside vehicle, remove cable clip (Fig. 1). (5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Remove cable housing at APPS bracket by pressing on release tab with a small screwdriver. To prevent cable housing breakage, press on tab only enough to release cable from APPS bracket.
Fig.52ACCELERATORCABLERELEASETAB-
4.7LV-8
1 - ACCELERATOR CABLE 2 - PLASTIC CABLE MOUNT 3 - PRESS TAB FOR REMOVAL 4 - CABLE BRACKET 5 - SLIDE FOR REMOVAL
5.9L V-8
CAUTION: Be careful not to damage or kink cable core wire (within cable sheathing) while servicing accelerator pedal or cables.
(1) From inside vehicle, hold up accelerator pedal. Remove plastic cable retainer and throttle cable core wire from upper end of pedal arm (Fig. 1). The plas- tic cable retainer snaps into pedal arm.
(2) Remove cable core wire at pedal arm. (3) Remove air resonator at throttle body. (4) From inside vehicle, remove cable clip (Fig. 1). (5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Disconnect cable from routing/holddown clip. (7) Slip cable end rearward from pin on throttle
body (Fig. 53).
(8) Remove cable housing at throttle body mount- ing bracket by pressing on release tab with a small screwdriver (Fig. 54). To prevent cable housing breakage, press on tab only enough to release cable from bracket. Lift cable housing straight up from bracket while pressing on release tab. Remove throttle cable from vehicle.
DR THROTTLE CONTROL CABLE (Continued)
FUEL INJECTION - GAS
14 - 51
(3) Remove necessary air intake tubes and resona-
tor housing.
(4) From inside vehicle, pinch both sides of plastic
cable housing retainer tabs at dash panel (Fig. 1).
(5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Remove throttle cable socket at throttle lever
ball (Fig. 55) (snaps off).
Fig.53THROTTLECABLEATTHROTTLEBODY-
5.9L
1 - THROTTLE LEVER PIN 2 - CAM (V-8 ENGINE ONLY) 3 - THROTTLE CABLE END
Fig.54CABLERELEASE-5.9LV-8
1 - TAB
8.0L V-10
CAUTION: Be careful not to damage or kink cable core wire (within cable sheathing) while servicing accelerator pedal or cables.
(1) From inside vehicle, hold up accelerator pedal. Remove plastic cable retainer and throttle cable core wire from upper end of pedal arm (Fig. 1). The plas- tic cable retainer snaps into pedal arm.
(2) Remove cable core wire at pedal arm.
Fig.55THROTTLECABLEATTHROTTLEBODY-
8.0LV-10
1 - PRESS TAB FOR CABLE REMOVAL 2 - THROTTLE CABLE 3 - CABLE SOCKET 4 - LEVER BALL 5 - MOUNTING BRACKET(7) Remove cable housing at throttle body mount- ing bracket by pressing on release tab with a small screwdriver (Fig. 55). To prevent cable housing breakage, press on tab only enough to release cable from bracket. Lift cable housing straight up from bracket while pressing on release tab. Remove throttle cable from vehicle.
INSTALLATION
3.7L V-6
(1) Slide accelerator cable plastic mount into throt- tle body mounting bracket. Continue sliding until release tab (Fig. 50) is aligned to hole in mounting bracket.
(2) Hold throttle in wide open position. While held in this position, slide throttle cable pin (Fig. 49) into throttle body bellcrank.
(3) Push cable housing into rubber grommet and
through opening in dash panel.
FUEL INJECTION - GAS
14 - 52
THROTTLE CONTROL CABLE (Continued)DR
(4) From inside vehicle, install metal clip holding
cable to dashpanel (Fig. 1).
(5) From inside vehicle, slide throttle cable core
wire into opening (slot) in top of pedal arm.
(2) Hold throttle in wide open position. While held in this position, slide throttle cable pin into throttle body bellcrank.
(3) Push cable housing into rubber grommet and
(6) Push plastic cable retainer (clip) into pedal arm
through opening in dash panel.
(5) Install rubber grommet into dash panel until
bracket (push down and lock)
opening until it snaps in place.
(7) Install air resonator tube to throttle body. (8) Before starting engine, operate accelerator
pedal to check for any binding.
4.7L V-8
(1) Slide accelerator
cable plastic mount
bracket. Continue sliding until aligned to hole in mounting bracket.
tab (Fig. 52)
into is
(2) Route accelerator cable over top of cable cam. (3) Connect cable end to throttle body bellcrank
pin (snaps on rearward).
(4) Slide rubber grommet away from plastic cable
housing.
seated.
(6) Push cable housing into rubber grommet and
through opening in dash panel.
(7) From inside vehicle, install clip holding cable
to dashpanel (Fig. 1).
(8) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(9) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(10) Snap cable into dashpanel routing clip. (11) Install air resonator tube to throttle body. (12) Before starting engine, operate accelerator
pedal to check for any binding.
5.7L V-8
(1) Attach cable to Accelerator Pedal Position Sen-
sor (APPS). Refer to APPS Removal / Installation.
(2) Push cable housing into rubber grommet and
through opening in dash panel.
(3) From inside vehicle, install clip holding cable
to dashpanel (Fig. 1).
(4) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(5) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(6) Before starting engine, operate accelerator
pedal to check for any binding.
(7) If necessary, use DRB IIIt Scan Tool to erase from
any APPS Diagnostic Trouble Codes (DTC’s) PCM.
5.9L V-8
(1) Slide accelerator cable plastic mount into throt- tle body mounting bracket. Continue sliding until release tab (Fig. 54) is aligned to hole in mounting bracket.
(4) From inside vehicle, install metal clip holding
cable to dashpanel (Fig. 1).
(5) From inside vehicle, slide throttle cable core
wire into opening (slot) in top of pedal arm.
(6) Push plastic cable retainer (clip) into pedal arm
opening until it snaps in place.
(7) Install air resonator tube to throttle body. (8) Before starting engine, operate accelerator
pedal to check for any binding.
8.0L V-10
(1) Connect cable end socket to throttle body lever
ball (snaps on) (Fig. 55). to
(2) Connect
cable
throttle body mounting
(3) Install the remaining cable housing end into and through the dash panel opening (snaps into posi- tion). The two plastic pinch tabs (Fig. 1) should lock the cable to dash panel.
(4) From inside the vehicle, hold up the accelera- tor pedal. Install the throttle cable core wire and plastic cable retainer into and through the upper end of the pedal arm (the plastic retainer is snapped into the pedal arm). When installing the plastic retainer to the accelerator pedal arm, note the index tab on the pedal arm (Fig. 1). Align the index slot on the plastic cable retainer to this index tab.
(5) Install air resonator tube to throttle body. (6) Before starting engine, operate accelerator
pedal to check for any binding.
THROTTLE POSITION SENSOR DESCRIPTION
The 3-wire Throttle Position Sensor
is mounted on the throttle body and is connected to the throttle blade shaft.
(TPS)
The 5.7L V-8 engine does not use a separate TPS
on the throttle body.
OPERATION
The 5.7L V-8 engine does not use a separate Throt-
tle Position Sensor (TPS) on the throttle body.
The 3–wire TPS provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents the throttle blade position of the throttle body. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the output voltage of the TPS changes.
DR THROTTLE POSITION SENSOR (Continued)
FUEL INJECTION - GAS
14 - 53
The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from .26
volts at minimum throttle opening (idle), to 4.49 volts at wide open throttle. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.The PCM needs to identify the actions and position of the throttle blade at all times. This information is needed to assist in performing the following calcula- tions:† Ignition timing advance † Fuel injection pulse-width † Idle (learned value or minimum TPS) † Off-idle (0.06 volt) † Wide Open Throttle (WOT) open loop (2.608
volts above learned idle voltage) † Deceleration fuel lean out † Fuel cutoff during cranking at WOT (2.608 volts † A/C WOT cutoff(certain automatic transmis-
above learned idle voltage)
sions only)
REMOVAL
3.7L V6
The Throttle Position Sensor (TPS) is mounted to
