1998 DODGE RAM 1500 Sensor

(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 IIItScan Tool to erase
any APPS Diagnostic Trouble Codes (DTC's) from
PCM.
THROTTLE POSITION SENSOR
DESCRIPTION
The 3-wire Throttle Position Sensor (TPS) is
mounted on the throttle body and is connected to the
throttle blade shaft.
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.
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:
²Ignition timing advance
²Fuel injection pulse-width
²Idle (learned value or minimum TPS)
²Off-idle (0.06 volt)
²Wide Open Throttle (WOT) open loop (2.608
volts above learned idle voltage)
²Deceleration fuel lean out
²Fuel cutoff during cranking at WOT (2.608 volts
above learned idle voltage)
²A/C WOT cutoff (certain automatic transmis-
sions only)
REMOVAL
3.7L V6
The Throttle Position Sensor (TPS) is mounted to
the throttle body (Fig. 37), or (Fig. 38).
(1) Remove air resonator tube at throttle body.
(2) Disconnect TPS electrical connector.
(3) Remove 2 TPS mounting screws.
(4) Remove TPS.
Fig. 37 TPS LOCATION - 3.7L V-6
1 - THROTTLE POSITION SENSOR (TPS)
2 - MOUNTING SCREWS
3 - IDLE AIR CONTROL MOTOR (IAC)
4 - MOUNTING SCREWS
DRFUEL INJECTION - GAS 14 - 41
THROTTLE CONTROL CABLE (Continued)

4.7L V-8
The TPS is located on the throttle body (Fig. 39).
(1) Remove air duct and tube at throttle body.
(2) Disconnect TPS electrical connector.
(3) Remove two TPS mounting bolts (screws) (Fig.
39).
(4) Remove TPS from throttle body.
5.7L V-8
The 5.7L V-8 engine does not use a separate Throt-
tle Position Sensor (TPS) on the throttle body.
Fig. 38 TPS INSTALLATION - 3.7 V-6
1 - THROTTLE BODY
2 - TPS
3 - THROTTLE BODY SHAFT
4 - SOCKET LOCATING TANGS
Fig. 39 TPS LOCATION - 4.7L
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR
5 - MOUNTING SCREWS
14 - 42 FUEL INJECTION - GASDR
THROTTLE POSITION SENSOR (Continued)

INSTALLATION
3.7L V-6
The Throttle Position Sensor (TPS) is mounted to
the throttle body (Fig. 37).
The throttle shaft end of throttle body slides into a
socket in TPS (Fig. 40). The TPS must be installed so
that it can be rotated a few degrees. (If sensor will
not rotate, install sensor with throttle shaft on other
side of socket tangs). The TPS will be under slight
tension when rotated.
(1) Install TPS and retaining screws.
(2) Tighten screws to 7 N´m (60 in. lbs.) torque.
(3) Connect TPS electrical connector to TPS.
(4) Manually operate throttle (by hand) to check
for any TPS binding before starting engine.
(5) Install air cleaner tube to throttle body.
4.7L V-8
The throttle shaft end of throttle body slides into a
socket in TPS (Fig. 41). The TPS must be installed so
that it can be rotated a few degrees. If sensor will
not rotate, install sensor with throttle shaft on other
side of socket tangs. The TPS will be under slight
tension when rotated.
(1) Install TPS and two retaining bolts.
(2) Tighten bolts to 7 N´m (60 in. lbs.) torque.
(3) Manually operate throttle control lever by hand
to check for any binding of TPS.
(4) Connect TPS electrical connector to TPS.
(5) Install air duct/air box to throttle body.
Fig. 40 TPS INSTALLATION - 3.7L
1 - THROTTLE BODY
2 - TPS
3 - THROTTLE BODY SHAFT
4 - SOCKET LOCATING TANGS
Fig. 41 TPS INSTALLATION - 4.7L
1 - THROTTLE BODY
2 - LOCATING TANGS
3 - THROTTLE POSITION SENSOR
4 - SOCKET
5 - THROTTLE SHAFT
DRFUEL INJECTION - GAS 14 - 43
THROTTLE POSITION SENSOR (Continued)

FUEL DELIVERY - DIESEL
TABLE OF CONTENTS
page page
FUEL DELIVERY - DIESEL
DESCRIPTION - DIESEL FUEL SYSTEM.....45
STANDARD PROCEDURE
STANDARD PROCEDURES - WATER
DRAINING AT FUEL FILTER..............47
STANDARD PROCEDURES - CLEANING
FUEL SYSTEM PARTS.................47
STANDARD PROCEDURE - FUEL SYSTEM
PRIMING............................47
SPECIFICATIONS
FUEL INJECTOR FIRING ORDER - DIESEL . 48
TORQUE - FUEL SYSTEM - DIESEL
ENGINE.............................48
SPECIAL TOOLS
DIESEL FUEL SYSTEM.................49
FUEL FILTER / WATER SEPARATOR
DESCRIPTION.........................50
OPERATION...........................50
REMOVAL.............................50
INSTALLATION.........................50
FUEL HEATER
DESCRIPTION.........................51
OPERATION...........................51
DIAGNOSIS AND TESTING - FUEL HEATER . . . 52
REMOVAL
REMOVAL/INSTALLATION...............52
FUEL HEATER RELAY
DESCRIPTION.........................52
OPERATION...........................52
REMOVAL.............................52
INSTALLATION.........................53
FUEL INJECTION PUMP
DESCRIPTION.........................53
OPERATION...........................53
DIAGNOSIS AND TESTING - FUEL INJECTION
PUMP TIMING........................53
REMOVAL.............................54
INSTALLATION.........................55
FUEL LEVEL SENDING UNIT / SENSOR
DESCRIPTION.........................57
OPERATION...........................57
REMOVAL
REMOVAL/INSTALLATION...............57FUEL LINES
DESCRIPTION.........................57
OPERATION...........................57
DIAGNOSIS AND TESTING - HIGH-
PRESSURE FUEL LINE LEAKS...........58
REMOVAL.............................58
INSTALLATION.........................60
FUEL PRESSURE SENSOR
DESCRIPTION.........................60
OPERATION...........................60
REMOVAL.............................60
INSTALLATION.........................61
FUEL PRESSURE LIMITING VALVE
DESCRIPTION.........................61
OPERATION...........................61
REMOVAL.............................61
INSTALLATION.........................61
FUEL TANK
DESCRIPTION - DIESEL..................62
REMOVAL - DIESEL.....................62
INSTALLATION - DIESEL.................62
FUEL TANK MODULE
DESCRIPTION.........................63
OPERATION...........................63
REMOVAL.............................63
INSTALLATION.........................64
FUEL TRANSFER PUMP
DESCRIPTION.........................64
OPERATION...........................64
REMOVAL.............................64
INSTALLATION.........................65
CASCADE OVERFLOW VALVE
DESCRIPTION.........................66
OPERATION...........................66
REMOVAL
REMOVAL/INSTALLATION...............66
WATER IN FUEL SENSOR
DESCRIPTION.........................66
OPERATION...........................66
REMOVAL.............................66
FUEL DRAIN CIRCUIT
OPERATION...........................67
14 - 44 FUEL DELIVERY - DIESELDR

FUEL DELIVERY - DIESEL
DESCRIPTION - DIESEL FUEL SYSTEM
The fuel system used on the Cummins engine is an
electronically controlled, Bosch HPCR (High-Pressure
Common Rail) system. The HPCR system consists of
five main components:
²Electric Fuel Transfer (lift) Pump
²Fuel Pump/Gear Pump (attached to fuel injec-
tion pump)
²High-Pressure Fuel Injection Pump
²Fuel Injection Rail
²Fuel Injectors
Also to be considered as part of the overall fuel
system are:
²Accelerator Pedal
²Air Cleaner Housing/Element
²Fuel Drain Manifold (passage)
²Fuel Drain Valve (at filter)
²Fuel Filter/Water Separator
²Fuel Heater
²Fuel Heater Relay
²Fuel Level (gauge) Sending Unit
²Fuel Pressure Limiting Valve
²Fuel Tank
²Fuel Tank Module (containing fuel gauge send-
ing unit and separate fuel filter located at bottom of
tank module)
²Fuel Tank Filler/Vent Tube Assembly
²Fuel Tank Filler Tube Cap
²Fuel Tubes/Lines/Hoses
²High-Pressure Fuel Injector Lines
²In-Tank Fuel Filter (at bottom of fuel tank mod-
ule)
²Low-Pressure Fuel Supply Lines
²Low-Pressure Fuel Return Line
²Overflow Valve
²Quick-Connect Fuel Line Fittings
²Throttle Cable
²Water Draining (maintenance)
²Water-In-Fuel (WIF) Sensor
The fuel injection pump supplies high pressure to
the fuel rail independent of engine speed. This high
pressure fuel is then accumulated in the fuel rail.
High pressure fuel is constantly supplied to the injec-
tors by the fuel rail. The Engine Control Module
(ECM) controls the fueling and timing of the engine
by actuating the injectors.Fuel enters the system from the electric fuel trans-
fer (lift) pump, which is attached to the fuel filter
assembly. Fuel is forced through the fuel filter ele-
ment and then enters the Fuel Pump/Gear Pump,
which is attached to the rear of the fuel injection
pump. The Fuel Pump/Gear Pump is a low-pressure
pump and produce pressures ranging from 551.5 kpa
(80 psi) to 1241 kpa (180) psi. Fuel then enters the
fuel injection pump. Low pressure fuel is then sup-
plied to the FCA (Fuel Control Actuator).
The FCA is an electronically controlled solenoid
valve. The ECM controls the amount of fuel that
enters the high-pressure pumping chambers by open-
ing and closing the FCA based on a demanded fuel
pressure. The FPS (Fuel Pressure Sensor) on the fuel
rail monitors the actual fuel pressure and provides it
as an input to the ECM. When the actuator is
opened, the maximum amount of fuel is being sup-
plied to the fuel injection pump. Any fuel that does
not enter the injection pump is directed to the over-
flow valve. The overflow valve regulates how much
excess fuel is used for lubrication of the pump and
how much is returned to the tank through the drain
manifold.
Fuel entering the injection pump is pressurized to
between 300-1600 bar (4351-23,206 psi) by three
radial pumping chambers. The pressurized fuel is
then supplied to the fuel rail.
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.
Certain fuel system components can be found in
(Fig. 1), or (Fig. 2).
DRFUEL DELIVERY - DIESEL 14 - 45

Fig. 1 DIESEL FUEL SYSTEM COMPONENTS
1 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR 14 - FUEL SUPPLY LINE (LOW-PRESSURE, TO ENGINE)
2 - THROTTLE LEVER BELLCRANK AND APPS (ACCELERATOR
PEDAL POSITION SENSOR)15 - FUEL RETURN LINE CONNECTION (TO FUEL TANK)
3 - INTAKE MANIFOLD AIR HEATER/ELEMENTS 16 - FUEL DRAIN TUBE
4 - FUEL PRESSURE SENSOR 17 - OIL PRESSURE SWITCH
5 - FUEL PRESSURE LIMITING VALVE 18 - ENGINE CONTROL MODULE (ECM)
6 - HIGH-PRESSURE FUEL LINES 19 - FUEL INJECTION PUMP
7 - FUEL HEATER 20 - CRANKSHAFT POSITION (ENGINE SPEED) SENSOR
8 - HIGH-PRESSURE FUEL RAIL 21 - CAMSHAFT POSITION SENSOR (CMP)
9 - FUEL HEATER TEMPERATURE SENSOR (THERMOSTAT) 22 - FUEL CONTROL ACTUATOR (FCA)
10 - FUEL FILTER/WATER SEPARATOR 23 - CASCADE OVERFLOW VALVE
11 - FUEL TRANSFER (LIFT) PUMP
12 - FUEL DRAIN MANIFOLD (CYLINDER HEAD FUEL RETURN
LINE)
13 - DRAIN VALVE
14 - 46 FUEL DELIVERY - DIESELDR
FUEL DELIVERY - DIESEL (Continued)

SPECIFICATIONS
FUEL INJECTOR FIRING ORDER - DIESEL
1±5±3±6±2±4
TORQUE - FUEL SYSTEM - DIESEL ENGINE
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Accelerator Pedal Bracket Mounting 12 - 105
Accelerator Pedal Position Sensor
Bracket-to-Battery Tray Bolts3-30
Crankshaft Position Sensor 9 80
Camshaft Position Sensor 9 - 80
Engine Coolant Temperature Sensor 18 15 160
Rear Engine Lift Bracket Bolts 77 56 -
Fuel Connector Nut at Cylinder Head 50 37 -
Fuel Filler Hose Clamp at Tank 3 - 30
Fuel Filler Housing-to-Body Screws 2 - 17
Fuel Filter Lid 34 25 -
Fuel Filter Drain Valve Screws 1.5 - 14
Fuel Heater Element Screws 1.5 - 14
Fuel Pump Module Lock Ring 54 40 -
Fuel Line Banjo Fitting Bolts 24 18 -
Fuel Line Fittings (High-Pressure - Pump
to Rail)37 27 -
Fuel Line Fittings (High-Pressure -
Cylinder head to Rail)30 22 -
Bracket Over #6 Fuel Line (Bolts) 43 32 -
Fuel Injector Solenoid Nuts 1.25 - 11
Fuel Injection Pump-to-Gear Shaft Nut 105 77 -
Fuel Injection Pump Mounting Nuts 24 18 -
Fuel Line Support Clamps (High-
Pressure)24 18 -
Fuel Pressure Sensor 70 52 -
Fuel Pressure Limiting Valve (Banjo Bolt) 24 17 -
Fuel Pressure Limiting Valve (In Fuel
Rail)70 52 -
Fuel Rail Mounting Bolts 24 18 200
Fuel Tank Mounting Straps 41 30 -
Map Sensor Mounting Screws 1 - 9
ECM-to-Engine Bracket Mounting Bolts 24 18 -
ECM Electrical Harness Connector 3 - 27
Water-In-Fuel Sensor 4.5 - 39
14 - 48 FUEL DELIVERY - DIESELDR
FUEL DELIVERY - DIESEL (Continued)

FUEL FILTER / WATER
SEPARATOR
DESCRIPTION
The fuel filter/water separator assembly is located
on left side of engine above the starter motor. The
assembly also includes the fuel heater, 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 in the owners
manual for the recommended 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 the
side of fuel filter housing. 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, or
the owners manual for recommended fuel filter
replacement intervals.
Draining water from fuel filter/water separa-
tor housing:
The housing drain valve (Fig. 3) serves two pur-
poses. One is topartiallythe drain filter housing of
excess water. The other is tocompletelythe drain
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 the water-in-fuel warning lamp remains
illuminated. (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) is located at the bottom of
drain valve. Place drain pan under drain hose.
(2)With engine not running,rotate drain valve
handle counter-clockwise (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, rotate valve handle
clockwise (forward) to the 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. 4) using a socket.
Attach socket to large hex on top of lid (Fig. 4).
Rotate counter-clockwise for removal. Remove
o-ring. Discard 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).
(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).
(a) Remove fuel filter. See previous steps.
(b) Disconnect electrical connector.
(c) Remove two T-15 Torx head mounting screws
from fuel heater element.
(d) Remove fuel heater.
(8)Drain Valve Replacement:The drain valve
assembly is located on the side of the fuel filter hous-
ing (Fig. 3).
(a) Disconnect drain hose from the fuel drain
valve.
(b) Remove 4 drain valve mounting screws (T-15
Torx head).
(c) Remove drain valve from filter housing.
INSTALLATION
Refer to maintenance schedules for recommended
fuel filter replacement intervals.
(1) Thoroughly clean inside of filter housing, filter
cap and all related components.
(2)Fuel Filter:
(a)The engine has a self-priming low-pres-
sure fuel system. Refer to Standard Proce-
dures-Fuel System Priming.
ENGINE ROTATING (BARRING) TOOL - #7471B
(ALSO PART OF KIT #6860)
14 - 50 FUEL DELIVERY - DIESELDR
FUEL DELIVERY - DIESEL (Continued)