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(5) Guide each injector into intake manifold. Be
body.
(12) Install air resonator mounting bracket near
front of throttle body (2 bolts).
(13) Connect fuel line latch clip and fuel line to
fuel rail. Refer to Quick-Connect Fittings.
(14) Install air box to throttle body. (15) Install air duct to air box. (16) Connect battery cable to battery. (17) Start engine and check for leaks.
4.7L V-8
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
fuel
injector machined bores in
(2) Clean out intake manifold.
(3) Apply a small amount of engine oil to each fuel injector o-ring. This will help in fuel rail installation. injector assembly to
(4) Position fuel
rail/fuel
machined injector openings in cylinder head.
(5) Guide each injector into cylinder head. Be care-
ful not to tear injector o-rings.
(6) Push right side of fuel rail down until fuel injectors have bottomed on cylinder head shoulder. Push left fuel rail down until injectors have bot- tomed on cylinder head shoulder.
(7) Install 4 fuel rail mounting bolts and tighten.
careful not to tear injector o-rings.
(6) Push right side of fuel rail down until fuel injectors have bottomed on shoulders. Push left fuel rail down until injectors have bottomed on shoulders. (7) Install 4 fuel rail holdown clamps and 4 mount-
ing bolts. Refer to Torque Specifications.
(8) Position spark plug cable tray and cable assem- bly to intake manifold. Snap 4 cable tray retaining clips into intake manifold.
(9) Install all cables to spark plugs and ignition
coils.
(10) Connect electrical connector to throttle body. (11) Install electrical connectors to all 8 ignition
coils. Refer to Ignition Coil Removal/Installation.
(12) Connect electrical connector to throttle body. (13) Connect electrical connectors at all fuel injec- tors. To install connector, refer to (Fig. 17). Push con- nector onto injector (1) and then push and lock red colored slider (2). Verify connector is locked to injec- tor by lightly tugging on connector.
(14) Connect fuel line latch clip and fuel line to
fuel rail. Refer to Quick-Connect Fittings.
(15) Install air resonator to throttle body (2 bolts). (16) Install flexible air duct to air box. (17) Connect battery cable to battery. (18) Start engine and check for leaks.
Refer to torque specifications.
(8) Install 8 ignition coils. Refer to Ignition Coil
5.9L V-8
Removal/Installation.
(9) Connect electrical connectors to throttle body. (10) Connect electrical connectors at all fuel injec- tors. To install connector, refer to (Fig. 17). Push con- nector onto injector (1) and then push and lock red colored slider (2). Verify connector is locked to injec- tor by lightly tugging on connector.
(11) Connect necessary vacuum lines to throttle
body.
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Apply a small amount of engine oil to each fuel injector o-ring. This will help in fuel rail installation. injector machined bores in
fuel
(3) Clean out intake manifold.
(4) Position fuel rail/fuel injector assembly to injec-
tor openings on intake manifold.
(5) Guide each injector into intake manifold. Be
(12) Install air resonator mounting bracket near
careful not to tear injector o-ring.
front of throttle body (2 bolts).
(13) Connect fuel line latch clip and fuel line to
fuel rail. Refer to Quick-Connect Fittings.
(14) Install air box to throttle body. (15) Install air duct to air box. (16) Connect battery cable to battery. (17) Start engine and check for leaks.
5.7L V-8
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
fuel
injector machined bores in
(2) Clean out intake manifold.
(3) Apply a small amount of engine oil to each fuel injector o-ring. This will help in fuel rail installation. injector assembly to
(4) Position fuel
rail/fuel
machined injector openings in intake manifold.
(6) Push the right fuel rail down until fuel injec- tors have bottomed on injector shoulder. Push the left fuel rail down until fuel injectors have bottomed on injector shoulder.
(7) Install fuel rail mounting bolts. Refer to Torque
Specifications.
(8) Connect electrical connector to intake manifold
air temperature sensor.
(9) Connect electrical connectors at all fuel injec- tors. To install connector, refer to (Fig. 17). Push con- nector onto injector (1) and then push and lock red colored slider (2). Verify connector is locked to injec- tor by lightly tugging on connector.
(10) Install fuel tube (line) at side of fuel rail.
Refer to Quick-Connect Fittings for procedures.
(11) Install air cleaner resonator to throttle body. (12) Connect battery cable to battery.
FUEL DELIVERY - GAS
14 - 20
FUEL RAIL (Continued)(13) Start engine and check for leaks.
8.0L V-10
(1) Apply a small amount of engine oil to each fuel injector o-ring. This will help in fuel rail installation. injector(s) and injector clip(s) to fuel
(2) Install
rail.
NOTE: The fuel injector electrical connectors on all 10 injectors should be facing to right (passenger) side of vehicle (Fig. 27).
(3) Position fuel rail/fuel injector assembly to injec-
tor openings on intake manifold.
(4) Guide each injector into intake manifold. Be
careful not to tear injector o-ring.
(5) Push the right fuel rail down until fuel injec- tors have bottomed on injector shoulder. Push the left fuel rail down until fuel injectors have bottomed on injector shoulder.
(6) Install six fuel rail mounting bolts into lower half of intake manifold. Tighten bolts to 15 N·m (136
in. lbs.) torque.(7) Connect electrical connectors at all fuel injec- tors. To install connector, refer to (Fig. 26). Push con- nector onto injector (1) and then push and lock red colored slider (2). Verify connector is locked to injec- tor by lightly tugging on connector. The injector wir- ing harness is numerically tagged.
(8) Install upper half of intake manifold. Refer to
Engines for procedures.
Quick-Connect Fittings for procedures.
(10) Install ignition coil pack and bracket assem- bly at intake manifold and right engine valve cover (four bolts).
(11) Install throttle body to intake manifold. Refer
to Throttle Body Removal / Installation.
(12) Install throttle body linkage to throttle body. (13) Install air cleaner tube and housing. (14) Install negative battery cable at battery. (15) Start engine and check for leaks.
FUEL TANK DESCRIPTION
The fuel tank is constructed of a plastic material. Its main functions are for fuel storage and for place- ment of the fuel pump module, and (if equipped) cer- tain ORVR components.
OPERATION
All models pass a full 360 degree rollover test without fuel leakage. To accomplish this, fuel and vapor flow controls are required for all fuel tank con- nections.
DR
Two check (control) valves are mounted into the top of the fuel tank. Refer to Fuel Tank Check Valve for additional information.
An evaporation control system is connected to the fuel tank to reduce emissions of fuel vapors into the atmosphere. When fuel evaporates from the fuel tank, vapors pass through vent hoses or tubes to a charcoal canister where they are temporarily held. When the engine is running, the vapors are drawn into the intake manifold. Certain models are also equipped with a self-diagnosing system using a Leak Detection Pump (LDP) and/or an On-Board Refueling Vapor Recovery (ORVR) system. Refer to Emission Control System for additional information.
REMOVAL- EXCEPT DIESEL
Fuel Tank Draining
WARNING: THE FUEL SYSTEM MAY BE UNDER CONSTANT FUEL PRESSURE EVEN WITH THE ENGINE OFF. PRESSURE MUST BE RELEASED BEFORE SERVICING FUEL TANK.
THIS
Two different procedures may be used to drain fuel tank: through the fuel fill fitting on tank, or using the DRBt scan tool. Due to a one-way check valve installed into the fuel fill opening fitting at the tank, the tank cannot be drained conventionally at the fill cap.
The quickest draining procedure involves removing
As an alternative procedure, the electric fuel pump may be activated allowing tank to be drained at fuel rail connection. Refer to DRB scan tool for fuel pump activation procedures. Before disconnecting fuel line at fuel rail, release fuel pressure. Refer to the Fuel System Pressure Release Procedure for procedures. Attach end of special test hose tool number 6541, 6539, 6631 or 6923 at fuel rail disconnection (tool number will depend on model and/or engine applica- tion). Position opposite end of this hose tool to an approved gasoline draining station. Activate fuel pump and drain tank until empty.
If electric fuel pump is not operating, fuel must be drained through fuel fill fitting at tank. Refer to fol- lowing procedures.
(1) Release fuel system pressure. (2) Raise vehicle. (3) Thoroughly clean area around fuel fill fitting
and rubber fuel fill hose at tank.
(4) If vehicle is equipped with 4 doors and a 6 foot
(short) box, remove left-rear tire/wheel.
(5) Loosen clamp (Fig. 28) and disconnect rubber fuel fill hose at tank fitting. Using an approved gas holding tank, drain fuel tank through this fitting.
(9) Connect main fuel line at fuel rail. Refer to
the rubber fuel fill hose.
DR FUEL TANK (Continued) Tank Removal
(1) Loosen clamp and disconnect rubber fuel vent
hose (Fig. 28) at tank fitting.
(2) Support tank with a hydraulic jack. (3) Remove 2 fuel tank strap nuts (Fig. 29) and
remove both tank support straps.
(4) Carefully lower tank a few inches and discon- nect fuel pump module electrical connector (Fig. 30) at top of tank. To disconnect electrical connector: Push upward on red colored tab to unlock. Push on black colored tab while removing connector.
FUEL DELIVERY - GAS
14 - 21
(5) Disconnect fuel line at fuel filter / fuel pressure regulator (Fig. 30) by pressing on tabs at side of quick-connect fitting.
(6) Disconnect EVAP line at top of tank (Fig. 1). (7) Continue to lower tank for removal. (8) If fuel tank is to be replaced, remove fuel pump module from tank. Refer to Fuel Pump Module Removal/Installation procedures.
1 - BEZEL SCREWS 2 - FUEL FILL BEZEL 3 - HOSE CLAMPS
Fig.28FUELTANKFILL/VENTHOSES
4 - VENT HOSE 5 - FUEL TANK 6 - FILL HOSE
FUEL DELIVERY - GAS
14 - 22
FUEL TANK (Continued)DR
Fig.29FUELTANKMOUNTING
4 - MOUNTING STRAPS 5 - STRAP NUTS
1 - FUEL TANK 2 - STRAP MOUNTING STUDS 3 - VEHICLE FRAME
INSTALLATION - EXCEPT DIESEL
(1) If fuel tank is to be replaced, install fuel pump module into tank. Refer to Fuel Pump Module Removal/Installation procedures.
(2) Disconnect clamps and remove rubber fuel fill hose and fuel vent hose at fuel fill tube. Install these 2 hoses to 2 fuel tank fittings. Rotate hoses until paint marks on hoses line up with alignment marks (Fig. 31). Tighten both clamps.
(3) Position fuel tank to hydraulic jack. (4) Raise tank until positioned near body. (5) Connect EVAP line at tank (Fig. 1). (6) Connect fuel pump module electrical connector
(Fig. 30) at top of tank.
(7) Connect fuel line quick-connect fitting to fuel
filter / fuel pressure regulator (Fig. 1) or (Fig. 30).
(8) Continue raising tank until positioned snug to
body.
(9) Install and position both tank support straps. Install 2 fuel tank strap nuts (Fig. 29) and tighten. Tighten rear strap nut first. Refer to Torque Spec- ifications.
(10) Connect rubber fill and vent hoses to fuel fill
tube and tighten clamps.
(11) Lower vehicle. (12) Fill fuel tank with fuel.
DR FUEL TANK (Continued)
FUEL DELIVERY - GAS
14 - 23
INLET FILTER REMOVAL
The fuel pump inlet filter (strainer) is located on the bottom of the fuel pump module (Fig. 32). The fuel pump module is located inside of fuel tank.
Fig.30FUELPUMPMODULECONNECTIONS
1 - TOP OF FUEL TANK 2 - FUEL PUMP MODULE 3 - FUEL FILTER / FUEL PRESSURE REGULATOR 4 - ELEC. CONNECT.
Fig.32FUELPUMPINLETFILTER
(13) Start engine and check for fuel leaks near top
of module.
1 - FUEL PUMP INLET FILTER 2 - LOCK TABS (2) 3 - FUEL PUMP MODULE (BOTTOM)
(1) Remove fuel tank. Refer to Fuel Tank Removal/
Installation.
(2) Remove fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
(3) Remove filter by carefully prying 2 lock tabs at bottom of module with 2 screwdrivers. Filter is snapped to module.
(4) Clean bottom of pump module.
INSTALLATION
The fuel pump inlet filter (strainer) is located on the bottom of the fuel pump module (Fig. 32). The fuel pump module is located inside of fuel tank.
(1) Snap new filter to bottom of module. Be sure
o-ring is in correct position.
(2) Install fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
(3) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
Fig.31HOSEALIGNMENTMARKS
1 - ALIGNMENT MARKS (MARK FOR FILL HOSE IS LOCATED ON FUEL TANK - MARK FOR VENT HOSE IS LOCATED ON FITTING) 2 - PAINT MARKS ON RUBBER HOSES
14 - 24
FUEL INJECTION - GAS
FUEL INJECTION - GAS
TABLE OF CONTENTS
page
DR
page
ACCELERATOR PEDAL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 24ACCELERATOR PEDAL POSITION SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 25
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 25CRANKSHAFT POSITION SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 26
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 30FUEL INJECTOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 32
OPERATIONOPERATION - FUEL INJECTOR OPERATION - PCM OUTPUT
. . . . . . . . . . 32
. . . . . . . . . . . . 32
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 33FUEL PUMP RELAY
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 33
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 33IDLE AIR CONTROL MOTOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 33
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34ACCELERATOR PEDAL REMOVAL
The following procedure applies only to vehicles
without the Adjustable Pedal Package (code XAP).
The accelerator pedal
is serviced as a complete
assembly including the bracket.
The accelerator cable is connected to the upper the accelerator pedal arm by a plastic part of retainer (clip) (Fig. 1). This plastic retainer snaps into the top of the accelerator pedal arm.
(1) From inside the vehicle, hold up accelerator pedal. Remove plastic cable retainer (clip) and throt- tle cable core wire from upper end of accelerator pedal arm (Fig. 1). Plastic cable retainer (clip) snaps into pedal arm.
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 35
INTAKE AIR TEMPERATURE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 36
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 38MAP SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 39
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 42OXYGEN SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 43
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 45THROTTLE BODY
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 45
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 47THROTTLE CONTROL CABLE
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 51THROTTLE POSITION SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 52
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 54(2) Remove 2 accelerator pedal mounting bracket
nuts. Remove accelerator pedal assembly.
INSTALLATION
(1) Place accelerator pedal assembly over 2 studs. (2) Install and tighten 2 mounting nuts. Refer to
Torque Specifications.
(3) Slide throttle cable into opening slot in top of
pedal arm.
(4) Push plastic cable retainer (clip) into accelera-
tor pedal arm opening until it snaps into place.
(5) Before starting engine, operate accelerator
pedal to check for any binding.
DR ACCELERATOR PEDAL (Continued)
FUEL INJECTION - GAS
14 - 25
REMOVAL
The APPS is serviced (replaced) as one assembly including the sensor, plastic housing and cable. The APPS assembly is located under the vehicle battery tray (Fig. 2). Access to APPS is gained from over top of left / front tire.
(1) Disconnect negative battery cable at battery. (2) Disconnect APPS cable at accelerator pedal.
Refer to Accelerator Pedal Removal / Installation.
(3) Remove wheel house liner at left / front wheel.
Refer to Body.
(4) Gain access to APPS electrical connector by opening swing-down door (Fig. 3). Disconnect electri- cal connector.
(5) Remove 3 mounting bolts (Fig. 3). (6) Remove APPS assembly from battery tray. (7) If cable is to be separated at APPS, unsnap cable clip from ball socket (Fig. 4). Release cable from plastic housing by pressing on small cable release tab (Fig. 3).
Fig.1ACCELERATORPEDALMOUNTING
1 - ACCELERATOR CABLE 2 - PLASTIC RETAINER (CLIP) 3 - THROTTLE PEDAL ARM 4 - PEDAL / BRACKET ASSEMBLY 5 - CABLE CLIP
ACCELERATOR PEDAL POSITION SENSOR DESCRIPTION
The Accelerator Pedal Position Sensor (APPS) assembly is located under the vehicle battery tray. A cable connects the assembly to the accelerator pedal. A plastic cover with a movable door is used to cover the assembly.
The APPS is used only with the 5.7L V-8 engine.
OPERATION
The Accelerator Pedal Position Sensor (APPS) is a linear potentiometer. It provides the Powertrain Con- trol Module (PCM) with a DC voltage signal propor- tional to the angle, or position of the accelerator pedal. The APPS signal is translated (along with other sensors) to place the throttle plate (within the throttle body) to a pre-determined position.
A mechanical cable is used between the accelerator pedal and the APPS assembly. Although a cable is used between the pedal and APPS, a mechanical cable is not used at the throttle body. Throttle plate position is electrically determined.
Fig.2APPSLOCATION
1 - BATTERY TRAY 2 - APPS LOCATION 3 - APPS MOUNTING BOLTS
INSTALLATION
(1) Install Accelerator Pedal Position Sensor (APPS) cable to accelerator pedal. Refer to Accelera- tor Pedal Removal / Installation.
(2) Connect electrical connector to APPS. (3) If necessary, connect cable to APPS lever ball
socket (snaps on).
(4) Snap APPS cable cover closed.
FUEL INJECTION - GAS
14 - 26
ACCELERATOR PEDAL POSITION SENSOR (Continued)DR
(5) Position APPS assembly to bottom of battery tray and install 3 bolts. Refer to Torque Specifica- tions.
(6) Install wheelhouse liner. Refer to Body. (7) Perform the following procedure:
(a) Connect negative battery cable to battery. (b) Turn ignition switch ON, but do not crank
engine.
(c) Leave ignition switch ON for a minimum of 10 seconds. This will allow PCM to learn electrical parameters. (8) If the previous step is not performed, a Diag-
nostic Trouble Code (DTC) will be set.
(9) If necessary, use DRB IIIt Scan Tool to erase
any Diagnostic Trouble Codes (DTC’s) from PCM.
Fig.3APPSREMOVE/INSTALL
1 - BOTTOM OF BATTERY TRAY 2 - ELECTRICAL CONNECTOR 3 - APPS 4 - SWING-DOWN DOOR 5 - CABLE (TO PEDAL) 6 - CABLE RELEASE TAB
Fig.4APPSCABLE
1 - APPS LEVER 2 - BALL SOCKET 3 - SWING-DOWN DOOR 4 - CABLE CLIP 5 - CABLE
CRANKSHAFT POSITION SENSOR DESCRIPTION
3.7L V-6
The Crankshaft Position (CKP) sensor is mounted into the right rear side of the cylinder block. It is positioned and bolted into a machined hole.
4.7L V-8
The Crankshaft Position (CKP) sensor is mounted into the right rear side of the cylinder block. It is positioned and bolted into a machined hole.
5.7L V-8
The Crankshaft Position (CKP) sensor is mounted into the right rear side of the cylinder block. It is positioned and bolted into a machined hole.
5.9L V-8 Gas
The Crankshaft Position (CKP) sensor is located near the outer edge of the flywheel (starter ringear). It is bolted to the rear of the engine.
8.0L V-10
The Crankshaft Position (CKP) sensor is located on the right-lower side of the cylinder block, forward of the right engine mount, just above the oil pan rail.
OPERATION
3.7L V-6
Engine speed and crankshaft position are provided through the CKP (Crankshaft Position) sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM inter- prets the sensor input to determine the crankshaft position. The PCM then uses this position, along with
DR CRANKSHAFT POSITION SENSOR (Continued)
FUEL INJECTION - GAS
14 - 27
other inputs, to determine injector sequence and igni- tion timing.
The sensor is a hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
A tonewheel (targetwheel) is bolted to the engine (Fig. 5). This tonewheel has sets of
crankshaft notches at its outer edge (Fig. 5).
The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.
Fig.6CKPSENSOROPERATIONANDTONEWHEEL
-4.7LV-8
1 - TONEWHEEL 2 - NOTCHES 3 - CRANKSHAFT POSITION SENSOR 4 - CRANKSHAFT
5.7L V-8
Engine speed and crankshaft position are provided through the crankshaft position sensor. The sensor generates pulses that are the input sent to the pow- ertrain control module (PCM). The PCM interprets the sensor input to determine the crankshaft posi- tion. The PCM then uses this position, along with other inputs, to determine injector sequence and igni- tion timing.
The sensor is a hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
On the 5.7L V–8 engine, a tonewheel is bolted to the engine crankshaft. This tonewheel has sets of notches at its outer edge (Fig. 7).
The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.
5.9L V-8 Gas
Engine speed and crankshaft position are provided through the CKP sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to deter- mine injector sequence and ignition timing.
Fig.5CKPOPERATION-3.7LV-6
1 - TONEWHEEL 2 - NOTCHES 3 - CRANKSHAFT POSITION SENSOR 4 - CRANKSHAFT
4.7L V-8
Engine speed and crankshaft position are provided through the crankshaft position sensor. The sensor generates pulses that are the input sent to the pow- ertrain control module (PCM). The PCM interprets the sensor input to determine the crankshaft posi- tion. The PCM then uses this position, along with other inputs, to determine injector sequence and igni- tion timing.
The sensor is a hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
On the 4.7L V–8 engine, a tonewheel is bolted to the engine crankshaft (Fig. 6). This tonewheel has sets of notches at its outer edge (Fig. 6).
The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.
FUEL INJECTION - GAS
14 - 28
CRANKSHAFT POSITION SENSOR (Continued)DR
Fig.7CKPSENSOROPERATIONANDNOTCHES-
5.7LV-8
1 - RIGHT / REAR SIDE OF CYLINDER BLOCK 2 - MACHINED HOLE 3 - NOTCHES
Fig.8CKPSENSOROPERATION–5.9LV-8
1 - CRANKSHAFT POSITION SENSOR 2 - NOTCHES 3 - FLYWHEEL
The sensor is a hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
On 5.9L V-8 engines, the flywheel/drive plate has 8
single notches, spaced every 45 degrees, at its outer edge (Fig. 8).The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM. For each engine revolution, there are 8
pulses generated on V-8 engines.The engine will not operate if the PCM does not
receive a CKP sensor input.
8.0L V-10
The Crankshaft Position (CKP) sensor detects notches machined into the middle of the crankshaft (Fig. 9).
There are five sets of notches. Each set contains two notches. Basic ignition timing is determined by the position of the last notch in each set of notches. Once the Powertrain Control Module (PCM) senses the last notch, it will determine crankshaft position (which piston will next be at Top Dead Center). An input from the camshaft position sensor is also needed. It may take the module up to one complete engine revolution to determine crankshaft position during engine cranking.
Fig.9CKPSENSOROPERATION–8.0LV-10
ENGINE
1 - CRANKSHAFT NOTCHES 2 - CRANKSHAFT 3 - CRANKSHAFT POSITION SENSOR
The PCM uses the signal from the camshaft posi- tion sensor to determine fuel injector sequence. Once crankshaft position has been determined, the PCM begins energizing a ground circuit to each fuel injec- tor to provide injector operation.
FUEL INJECTION - GAS
14 - 29
DR CRANKSHAFT POSITION SENSOR (Continued) REMOVAL
3.7L V-6
The Crankshaft Position (CKP) sensor is mounted into the right rear side of the cylinder block (Fig. 10). It is positioned and bolted into a machined hole.
(1) Raise vehicle. (2) Disconnect sensor electrical connector. (3) Remove sensor mounting bolt (Fig. 10). (4) Carefully twist sensor from cylinder block. (5) Check condition of sensor o-ring.
Fig.11CKPREMOVAL/INSTALLATION-4.7L
1 - CRANKSHAFT POSITION SENSOR 2 - MOUNTING BOLT
(2) Disconnect CKP electrical connector at sensor. (3) Remove CKP mounting bolt (Fig. 11). (4) Carefully twist sensor from cylinder block. (5) Remove sensor from vehicle. (6) Check condition of sensor o-ring.
5.7L V-8
Fig.10CKPREMOVAL/INSTALLATION-3.7L
1 - MOUNTING BOLT 2 - CKP SENSOR 3 - O-RING
4.7L V-8
The Crankshaft Position (CKP) sensor is located at the right-rear side of the engine cylinder block (Fig. 11). It is positioned and bolted into a machined hole in the engine block. (1) Raise vehicle.
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
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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.
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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
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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.
