2003 DODGE RAM app

STANDARD PROCEDURE - FUEL SYSTEM
PRIMING
A certain amount of air becomes trapped in the
fuel system when fuel system components on the
supply and/or high-pressure side are serviced or
replaced. Fuel system priming is accomplished using
the electric fuel transfer (lift) pump.
Servicing or replacing fuel system components usu-
ally will not require fuel system priming.
The fuel transfer (lift) pump is self-priming: When
the key is first turned on (without cranking engine),
the pump operates for approximately 2 seconds and
then shuts off. The pump will also operate for up to25 seconds after the starter is quickly engaged, and
then disengaged without allowing the engine to start.
The pump shuts off immediately if the key is on and
the engine stops running.
(1) Turn key to CRANK position and quickly
release key to ON position before engine starts. This
will operate fuel transfer pump for approximately 25
seconds.
(2) If the engine does not start after 25 seconds,
turn key OFF. Repeat previous step until engine
starts.
(3) Fuel system priming is now completed.
(4) Attempt to start engine. If engine will not
start, proceed to following steps.When engine does
start, it may run erratically and be noisy for a
few minutes. This is a normal condition.
CAUTION: Do not engage the starter motor for more
than 30 seconds at a time. Allow two minutes
between cranking intervals.
(5) Perform previous fuel priming procedure steps
using fuel transfer pump. Be sure fuel is present at
fuel tank.
(6) Crank the engine for 30 seconds at a time to
allow fuel system to prime.
WARNING: THE FUEL INJECTION PUMP SUPPLIES
EXTREMELY HIGH FUEL PRESSURE TO EACH INDI-
VIDUAL INJECTOR THROUGH THE HIGH-PRES-
SURE LINES. FUEL UNDER THIS AMOUNT OF
PRESSURE CAN PENETRATE THE SKIN AND
CAUSE PERSONAL INJURY. WEAR SAFETY GOG-
GLES AND ADEQUATE PROTECTIVE CLOTHING.
DO NOT LOOSEN FUEL FITTINGS WHILE ENGINE
IS RUNNING.
WARNING: ENGINE MAY START WHILE CRANKING
STARTER MOTOR.
Fig. 2 FUEL INJECTORS
1 - SOLENOID CONNECTIONS
2 - ROCKER HOUSING
3 - FUEL INJECTOR
4 - PASSTHROUGH CONNECTOR
DRFUEL DELIVERY - DIESEL 14 - 59
FUEL DELIVERY - DIESEL (Continued)

FUEL FILTER / WATER
SEPARATOR
DESCRIPTION
The fuel filter/water separator assembly is located
on left side of engine above starter motor. The assem-
bly also includes the fuel heater and Water-In-Fuel
(WIF) sensor, and fuel transfer pump.
OPERATION
The fuel filter/water separator protects the fuel
injection pump by removing water and contaminants
from the fuel. The construction of the filter/separator
allows fuel to pass through it, but helps prevent
moisture (water) from doing so. Moisture collects at
the bottom of the canister.
Refer to the maintenance schedules for the recom-
mended fuel filter replacement intervals.
For draining of water from canister, refer to Fuel
Filter/Water Separator Removal/Installation section.A Water-In-Fuel (WIF) sensor is attached to side of
canister. Refer to Water-In-Fuel Sensor Description/
Operation.
The fuel heater is installed into the top of the fil-
ter/separator housing. Refer to Fuel Heater Descrip-
tion/Operation.
REMOVAL
Refer to maintenance schedules in this manual for
recommended fuel filter replacement intervals.
Draining water from fuel filter/water separa-
tor housing:
The housing drain valve (Fig. 3) or (Fig. 4) serves
two purposes. One is topartiallydrain filter hous-
ing of excess water. The other is tocompletelydrain
housing for fuel filter, drain valve, heater element, ,
water-in-fuel sensor replacement or transfer pump
replacement.
The filter housing should be partially drained
whenever water-in-fuel warning lamp remains illumi-
nated. (Note that lamp will be illuminated for
approximately two seconds when ignition key is ini-
tially placed in ON position for a bulb check).
(1) A drain hose (Fig. 3) or (Fig. 4) is located at
bottom of drain valve. Place drain pan under drain.
(2)With engine not running,rotate drain valve
handle rearward to OPEN (DRAIN) position. Hold
drain valve open until all water and contaminants
have been removed and clean fuel exits.
(3) If drain valve, fuel heater element or Water-In-
Fuel (WIF) sensor is being replaced, drain housing
completely. Dispose of mixture in drain pan according
to applicable regulations.
(4) After draining operation, push valve handle
forward to CLOSE position.
(5)Fuel Filter Replacement:The fuel filter is
located inside of the fuel filter housing.
(a) Clean all debris from around canister.
(b) Remove filter lid (Fig. 5) using a socket.
Attach socket to large hex on top of lid (Fig. 5).
Rotate counter-clockwise for removal. Remove
o-ring.
(c) Remove filter element by twisting element
sideways from filter lid.
(6)Water-In-Fuel (WIF) Sensor Replacement:
The WIF sensor is located on the side of the fuel fil-
ter housing (Fig. 3) or (Fig. 4).
(a) Disconnect electrical connector at sensor.
(b) Clean area around sensor.
(c) Remove sensor by rotating counter-clockwise.
(d) Check condition of sensor o-ring. Replace if
damaged.
(7)Fuel Heater Element Replacement:The
heater element is located in the fuel filter housing
(Fig. 3) or (Fig. 4).
(a) Remove fuel filter. See previous steps.
FUEL INJECTOR TUBE (CONNECTOR) REMOVER -
#9015
SPANNER WRENCH (FUEL TANK MODULE
REMOVAL/INSTALLATION) - #6856
ENGINE ROTATING (BARRING) TOOL - #7471B
(ALSO PART OF KIT #6860)
DRFUEL DELIVERY - DIESEL 14 - 61
FUEL DELIVERY - DIESEL (Continued)

(c) Position new element to canister lid. Place
this assembly into canister by rotating clockwise.
(d) Tighten cap to 34 N´m (25 ft. lbs.) torque. Do
not overtighten cap.
(3)Water-In-Fuel (WIF) Sensor:
(a) Install new o-ring seal to WIF sensor.
(b) Apply a light film of clean diesel oil to o-ring
seal.
(c) Install sensor into housing.
(d) Tighten sensor to 4.5 N´m (39 in. lbs.) torque.
(e) Connect electrical connector to WIF sensor.
(4)Fuel Heater Element:
(a) Install fuel heater into fuel filter housing.
(b) Install fuel heater thermostat into fuel filter
housing.
(c) Install fuel heater mounting screws and
tighten to 1-1.5 N´m torque.
(d) Connect electrical connector to fuel heater
thermostat.
(e) Install new filter cover O-ring onto fuel filter
housing cover and lubricate with 30W oil.
(f) Tighten fuel filter housing cover (lid) to 34
N´m (25 ft. lbs.).
(5)Drain Valve:
(a) Install 2 new o-rings to valve and filter hous-
ing.
(b) Lubricate with silicon grease.
(c) Install fuel drain valve.
(d) Install 4 mounting screws and tighten to
1±1.5 N´m (8±13 in. lbs.) torque.
(e) Connect drain hose to drain valve.
(6) Start engine and check for leaks.
FUEL HEATER
DESCRIPTION
The fuel heater assembly is located on the side of
the fuel filter housing (Fig. 3) or (Fig. 4).
The heater/element assembly is equipped with a
temperature sensor (thermostat) that senses fuel
temperature. This sensor is attached to the fuel heat-
er/element assembly.
OPERATION
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
When the temperature is below 45  8 degrees F,
the temperature sensor allows current to flow to the
heater element warming the fuel. When the temper-
ature is above 75  8 degrees F, the sensor stops cur-
rent flow to the heater element.
Battery voltage to operate the fuel heater element
is supplied from the ignition switch and through the
fuel heater relay. Also refer to Fuel Heater Relay.The fuel heater element and fuel heater relay
are not computer controlled.
The heater element operates on 12 volts, 300 watts
at 0 degrees F.
DIAGNOSIS AND TESTING - FUEL HEATER
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
NOTE: The fuel heater element, fuel heater relay
and fuel heater temperature sensor are not con-
trolled by the Engine Control Module (ECM), or the
Powertrain Control Module (PCM).
A malfunctioning fuel heater can cause a wax
build-up in the fuel filter/water separator. Wax
build-up in the filter/separator can cause engine
starting problems and prevent the engine from rev-
ving up. It can also cause blue or white fog-like
exhaust. If the heater is not operating in cold tem-
peratures, the engine may not operate due to fuel
waxing.
The fuel heater assembly is located on the side of
fuel filter housing.
The heater assembly is equipped with a built-in
fuel temperature sensor (thermostat) that senses fuel
temperature. When fuel temperature drops below 45
degrees   8 degrees F, the sensor allows current to
flow to built-in heater element to warm fuel. When
fuel temperature rises above 75 degrees   8 degrees
F, the sensor stops current flow to heater element
(circuit is open).
Voltage to operate fuel heater element is supplied
from ignition switch, through fuel heater relay (also
refer to Fuel Heater Relay), to fuel temperature sen-
sor and on to fuel heater element.
The heater element operates on 12 volts, 300 watts
at 0 degrees F. As temperature increases, power
requirements decrease.
A minimum of 7 volts is required to operate fuel
heater. The resistance value of heater element is less
than 1 ohm (cold) and up to 1000 ohms warm.
TESTING
(1) Disconnect electrical connector from thermostat
(Fig. 3) or (Fig. 4).
Ambient temperature must be below circuit close
temperature, If necessary, induce this ambient tem-
perature by placing ice packs on thermostat to pro-
duce an effective ambient temperature below circuit
close temperature. For first check of thermostat you
can hear click of thermostat when circuit closes.
Measure resistance across two pins. Operating
range is 0.3 Ð 0.45 Ohms.
(2) If resistance is out of range, remove thermostat
and check resistance across terminal connections of
DRFUEL DELIVERY - DIESEL 14 - 63
FUEL FILTER / WATER SEPARATOR (Continued)

(4) Apply clean engine oilto injection pump
o-ring only.
The machined tapers on both injection pump
shaft and injection pump gear must be abso-
lutely dry, clean and free of any dirt or oil film.
This will ensure proper gear-to-shaft tighten-
ing.
(5) Clean pump gear and pump shaft at machined
tapers with an evaporative type cleaner such as
brake cleaner.
(6) Position injection pump to mounting flange on
gear cover while aligning injection pump shaft
through back of injection pump gear.
(7) After pump is positioned flat to mounting
flange, install 3 pump mounting nuts and tighten
finger tight only.Do not attempt a final tightening
at this time.Do not attempt to tighten (pull)
pump to gear cover using mounting nuts. Dam-
age to pump or gear cover may occur. The
pump must be positioned flat to its mounting
flange before attempting to tighten 3 mounting
nuts.
(8) To prevent damage or cracking of components,
install and tighten nuts in the following sequence:
(a) Install injection pump shaft washer and nut
to pump shaft. Tighten nutfinger tight only.
(b) Do preliminary (light) tightening of injection
pump shaft nut.
(c) Tighten 3 injection pump mounting nuts to 8
N´m (70.8 in. lbs.).
(d) Do a final tightening of pump shaft nut to
105 N´m (77 ft. lbs.).
(9) Install drive gear access cover (plate) using a
1/2 inch drive ratchet. Plate is threaded to timing
gear cover.
(10) Install Engine Control Module (ECM) to left
side of engine.
(11) Install fuel line (injection pump-to-overflow
valve). Tighten bolts to 24 N´m (17 ft. lbs.) torque.
(12) Install fuel line (injection pump-to-fuel rail).
Tighten to 24 N´m (17 ft. lbs.) torque.
(13) Install fuel line (injection pump-to-fuel filter
housing). Tighten to 24 N´m (17 ft. lbs.) torque.
(14) Connect Fuel Control Actuator (FCA) electri-
cal connector to rear of injection pump.
(15) Install intake manifold air intake tube (above
injection pump). Tighten clamps.
(16) Install accessory drive belt.
(17) Install cooling fan shroud.
(18) Install cooling fan assembly.
(19) Connect both negative battery cables to both
batteries.
(20) Check system for fuel or engine oil leaks.FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel tank module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel tank module on diesel powered models
has 3 different circuits (wires). Two of these circuits
are used at the fuel gauge sending unit for fuel
gauge operation. The other wire is used for a ground.
The diesel engine does not have a fuel tank module
mounted electric fuel pump. The electric fuel pump
(fuel transfer pump) is mounted to the engine.
For Fuel Gauge Operation:A constant input
voltage source of about 12 volts (battery voltage) is
supplied to the resistor track on the fuel gauge send-
ing unit. This is fed directly from the Powertrain
Control Module (PCM).NOTE: For diagnostic pur-
poses, this 12V power source can only be veri-
fied with the circuit opened (fuel tank module
electrical connector unplugged). With the con-
nectors plugged, output voltages will vary from
about .6 volts at FULL, to about 7.0 volts at
EMPTY.The resistor track is used to vary the volt-
age (resistance) depending on fuel tank float level. As
fuel level increases, the float and arm move up,
which decreases voltage. As fuel level decreases, the
float and arm move down, which increases voltage.
The varied voltage signal is returned back to the
ECM through the sensor return circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the ECM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the ECM, the ECM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
REMOVAL
REMOVAL/INSTALLATION
For diesel removal and installation procedures,
refer to the gas section of Fuel System/Fuel Delivery.
See Fuel Level Sending Unit/Sensor Removal/Instal-
lation.
14 - 68 FUEL DELIVERY - DIESELDR
FUEL INJECTION PUMP (Continued)

FUEL LINES
DESCRIPTION
Low-Pressure Lines
²the fuel supply line from fuel tank to fuel trans-
fer (lift) pump.
²the fuel return line back to fuel tank.
²the fuel drain manifold line at rear of cylinder
head.
²the fuel supply line from fuel filter to fuel injec-
tion pump.
High-Pressure Lines
²the fuel line from fuel injection pump to overflow
valve.
²the fuel line from fuel injection pump to fuel
rail.
²the 6 fuel lines from fuel rail up to injector con-
nector tubes
WARNING: HIGH-PRESSURE FUEL LINES DELIVER
DIESEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 160,000 KPA (23,206
PSI). USE EXTREME CAUTION WHEN INSPECTING
FOR HIGH-PRESSURE FUEL LEAKS. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. HIGH FUEL INJECTION PRESSURE
CAN CAUSE PERSONAL INJURY IF CONTACT IS
MADE WITH THE SKIN.
OPERATION
High-Pressure Lines
CAUTION: The high-pressure fuel lines must be
held securely in place in their holders. The lines
cannot contact each other or other components. Do
not attempt to weld high-pressure fuel lines or to
repair lines that are damaged. If lines are ever
kinked or bent, they must be replaced. Use only the
recommended lines when replacement of high-pres-
sure fuel line is necessary.
High-pressure fuel lines deliver fuel (under pres-
sure) of up to approximately 160,000 kPa (23,206
PSI) from the injection pump to the fuel injectors.
The lines expand and contract from the high-pres-
sure fuel pulses generated during the injection pro-
cess. All high-pressure fuel lines are of the same
length and inside diameter. Correct high-pressure
fuel line usage and installation is critical to smooth
engine operation.WARNING: USE EXTREME CAUTION WHEN
INSPECTING FOR HIGH-PRESSURE FUEL LEAKS.
INSPECT FOR HIGH-PRESSURE FUEL LEAKS WITH
A SHEET OF CARDBOARD. HIGH FUEL INJECTION
PRESSURE CAN CAUSE PERSONAL INJURY IF
CONTACT IS MADE WITH THE SKIN.
DIAGNOSIS AND TESTING - HIGH-PRESSURE
FUEL LINE LEAKS
High-pressure fuel line leaks can cause starting
problems and poor engine performance.
WARNING: DUE TO EXTREME FUEL PRESSURES
OF UP TO 160,000 kPa (23,206 PSI), USE EXTREME
CAUTION WHEN INSPECTING FOR HIGH-PRES-
SURE FUEL LEAKS. DO NOT GET YOUR HAND OR
A FINGER NEAR A SUSPECTED LEAK. INSPECT
FOR HIGH-PRESSURE FUEL LEAKS WITH A SHEET
OF CARDBOARD. HIGH FUEL INJECTION PRES-
SURE CAN CAUSE PERSONAL INJURY IF CON-
TACT IS MADE WITH THE SKIN.
Start the engine. Move the cardboard (Fig. 15) over
the suspected high-pressure fuel line leak, and check
for fuel spray onto the cardboard. If line is leaking,
retorque line. Replace damaged, restricted or leaking
high-pressure fuel lines with the correct replacement
line.
CAUTION: The high-pressure fuel lines must be
clamped securely in place in the holders. The lines
cannot contact each other or other components. Do
not attempt to weld high-pressure fuel lines or to
repair lines that are damaged. Only use the recom-
mended lines when replacement of high-pressure
fuel line is necessary.
REMOVAL
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines and fuel injection pump.
Very tight tolerances are used with these parts. Dirt
contamination could cause rapid part wear and pos-
sible plugging of fuel injector nozzle tip holes. This
in turn could lead to possible engine misfire.
Always wash/clean any fuel system component
thoroughly before disassembly and then air dry.
Cap or cover any open part after disassembly.
Before assembly, examine each part for dirt, grease
or other contaminants and clean if necessary. When
installing new parts, lubricate them with clean
engine oil or clean diesel fuel only.
DRFUEL DELIVERY - DIESEL 14 - 69

INSTALLATION
(1) Be sure both top of manifold and limiting valve
are clean.
(2) Assemble banjo bolt and new sealing washers
to limiting valve.
(3) Tighten banjo bolt to 24 N´M (17 ft. lbs.)
torque.
FUEL TANK
DESCRIPTION - DIESEL
The fuel tank is similar to the tank used with gas-
oline powered models. The tank is equipped with a
separate fuel return line and a different fuel tank
module for diesel powered models. A fuel tank
mounted, electric fuel pump is not used with diesel
powered models. Refer to Fuel Tank Module for addi-
tional information.
REMOVAL - DIESEL
Fuel Tank Draining
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.
(1) Raise vehicle.(2) If vehicle is equipped with 4 doors and a 6 foot
(short) box, remove left-rear tire/wheel.
(3) Thoroughly clean area at top of fuel tank
around fuel tank module.
(4) Remove rubber cap from auxiliary fitting on
top of tank module (Fig. 21).
(5) Drain fuel tank by attaching drain hose from
an approved draining station to auxiliary fitting on
top of tank module (Fig. 21).
Tank Removal
(1) Loosen clamp and disconnect rubber fuel fill
hose at tank.
(2) Support tank with a hydraulic jack.
(3) Remove 2 fuel tank strap nuts (Fig. 22) and
remove both tank support straps.
(4) Carefully lower tank a few inches and discon-
nect fuel pump module electrical connector (Fig. 21)
at top of tank. To disconnect electrical connector:
Push upward on red colored tab to unlock. Push on
black colored tab while removing connector.
(5) Disconnect fuel supply and return lines at fuel
tank module (Fig. 21). Refer to Quick-Connect Fit-
tings for procedures.
(6) Continue to lower tank for removal.
Fig. 20 FUEL PRESSURE SENSOR/FUEL
PRESSURE LIMITING VALVE
1 - ELEC. CONNECTOR
2 - BANJO BOLT
3 - FUEL PRESSURE LIMITING VALVE
4 - FUEL PRESSURE SENSOR
5 - TOP OF INTAKE HEATER MANIFOLD
Fig. 21 FUEL TANK MODULE - DIESEL
1 - TOP OF FUEL TANK
2 - AUX. FITTING
3 - ELEC. CONNECTOR
4 - FUEL TANK MODULE (TOP)
5 - LOCKNUT
6 - FUEL SUPPLY LINE
7 - FUEL RETURN LINE
DRFUEL DELIVERY - DIESEL 14 - 73
FUEL PRESSURE LIMITING VALVE (Continued)

OPERATION
The purpose of the fuel transfer pump is to supply
(transfer) a low-pressure fuel source:fromthe fuel
tank,throughthe fuel filter/water separator andto
the fuel injection pump. Here, the low-pressure is
raised to a high-pressure by the fuel injection pump
for operation of the high-pressure fuel injectors.
Check valves within the pump, control direction of
fuel flow and prevent fuel bleed-back during engine
shut down.
Maximum current flow to the pump is 5 amperes.
With the engine running, the pump has a 100 per-
cent duty-cycle with a minimum pressure of 11.5 psi.
The transfer pump is self-priming: When the key is
first turned on (without cranking engine), the pump
will operate for approximately 1/2 second and then
shut off. The pump will also operate for up to 25 sec-
onds after the starter is engaged, and then disen-
gaged and the engine is not running. The pump
shuts off immediately if the key is on and the engine
stops running.
The fuel volume of the transfer pump will always
provide more fuel than the fuel injection pump
requires. Excess fuel is returned from the injection
pump through an overflow valve, and then back to
the fuel tank.
REMOVAL
The fuel transfer pump (fuel lift pump) is attached
to the rear of the fuel filter/water separator housing
(Fig. 25).
(1) Drain fuel from fuel filter housing. Refer to
Fuel Filter/Water Separator - Removal. See Draining.
(2) Disconnect electrical connector (Fig. 25) from
fuel transfer pump.
(3) Disconnect fuel tank supply line from fuel
transfer pump extension line. Do this at disconnec-
tion point at inside of left inner frame rail (Fig. 26).
Refer to quick-connect fittings for procedures.The
fuel line extension is permanently attached to
the transfer pump. Do not attempt to discon-
nect fuel line at transfer pump.
(4) Remove 4 pump mounting bolts (hex-allen),
and remove pump from fuel filter housing.
(5) Confirm that transfer pump o-ring is also
removed from fuel filter housing.
INSTALLATION
(1) Install a new o-ring to fuel transfer pump.
(2) Lubricate o-ring and OD of transfer pump inlet
connector.
(3) Position fuel transfer pump onto fuel filter
housing.Do not use mounting bolts to draw
transfer pump to filter housing.
Fig. 25 FUEL TRANSFER (LIFT) PUMP
1 - FILTER HOUSING
2 - ELEC. CONNECTOR
3 - FUEL TRANSFER (LIFT) PUMP
4 - FUEL LINE EXTENTION
5 - MOUNTING BOLTS (4)
Fig. 26 TRANSFER PUMP FUEL LINE CONNECT
1 - LEFT INNER FRAME RAIL
2 - FUEL RETURN LINE
3 - FUEL SUPPLY LINE
4 - QUICK-CONNECT FITTING
14 - 76 FUEL DELIVERY - DIESELDR
FUEL TRANSFER PUMP (Continued)

FUEL INJECTION - DIESEL
TABLE OF CONTENTS
page page
ACCELERATOR PEDAL POSITION SENSOR
DESCRIPTION
DESCRIPTION (EARLY)................79
DESCRIPTION (LATE)..................79
OPERATION...........................79
REMOVAL.............................79
INSTALLATION.........................82
CAMSHAFT POSITION SENSOR
DESCRIPTION.........................82
OPERATION...........................82
REMOVAL.............................83
INSTALLATION.........................83
CRANKSHAFT POSITION SENSOR
DESCRIPTION.........................83
OPERATION...........................83
REMOVAL.............................84
INSTALLATION.........................84
FUEL CONTROL ACTUATOR
DESCRIPTION.........................85
OPERATION...........................85
REMOVAL.............................85
INSTALLATION.........................85
FUEL INJECTOR
DESCRIPTION.........................85
OPERATION...........................86
REMOVAL.............................87
INSTALLATION.........................87
FUEL INJECTOR RAIL
DESCRIPTION.........................89
OPERATION...........................89REMOVAL.............................89
INSTALLATION.........................90
INLET AIR TEMPERATURE SENSOR/
PRESSURE SENSOR
DESCRIPTION.........................90
OPERATION...........................90
REMOVAL.............................90
INSTALLATION.........................90
INTAKE AIR HEATER
DESCRIPTION.........................91
OPERATION...........................91
REMOVAL.............................91
INSTALLATION.........................91
INTAKE AIR HEATER RELAY
DESCRIPTION.........................92
OPERATION...........................92
REMOVAL.............................93
INSTALLATION.........................93
INTAKE AIR TEMPERATURE SENSOR/MAP
SENSOR
DESCRIPTION.........................93
OPERATION...........................93
REMOVAL.............................93
INSTALLATION.........................94
MAP SENSOR
DESCRIPTION.........................94
THROTTLE CONTROL CABLE
REMOVAL.............................94
INSTALLATION.........................96
ACCELERATOR PEDAL
POSITION SENSOR
DESCRIPTION
DESCRIPTION (EARLY)
The APPS assembly is located at the top-left-front
of the engine. A plastic cover is used to cover the
assembly. The actual sensor is located behind its
mounting bracket.
DESCRIPTION (LATE)
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.
OPERATION
The Accelerator Pedal Position Sensor (APPS) is a
linear potentiometer. It provides the Engine Control
Module (ECM) with a DC voltage signal proportional
to the angle, or position of the accelerator pedal.
REMOVAL
Early Diesel Engines
The APPS is serviced (replaced) as one assembly
including the lever, brackets and sensor. The APPS is
calibrated to its mounting bracket. The APPS assem-
bly is located at left-front of engine below plastic
cable/lever/linkage cover (Fig. 1).
DRFUEL INJECTION - DIESEL 14 - 79