2003 DODGE RAM fuel type

(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 CONTROL ACTUATOR
DESCRIPTION
The Fuel Control Actuator (FCA) is located at the
rear of the high-pressure, fuel injection pump.
OPERATION
The Fuel Control Actuator (FCA) is an electroni-
cally controlled solenoid valve. The ECM controls the
amount of fuel that enters the high-pressure pumping
chambers by opening and closing the FCA based on a
demanded fuel pressure. When the FCA is opened,
the maximum amount of fuel is being supplied to the
fuel injection pump. Any fuel that does not enter the
injection pump is directed to the overflow valve. The
overflow valve regulates how much excess fuel is used
for lubrication of the pump and how much is returned
to the fuel tank through the drain manifold.
An audible click from the FCA is normal when
operating the key to either the ON or OFF positions.
REMOVAL
The Fuel Control Actuator (FCA) is located at the
rear of the high-pressure, fuel injection pump (Fig. 13).
(1) Clean FCA mounting area at rear of fuel injec-
tion pump with an evaporative-type cleaner.
(2) Disconnect electrical connector at FCA.
(3) Remove 2 FCA mounting bolts.
(4) Remove FCA from injection pump.
(5) After removal, inspect FCA for corrosion or
damage. Shake the FCA and listen for a rattle. If
FCA does not rattle, replace it.
INSTALLATION
(1) Install new o-rings to the Fuel Control Actua-
tor (FCA).
(2) Lubricate o-rings with clean, light grease.
(3) Using new mounting bolts, install FCA into
injection pump. Tighten the micro-encapsulated bolts
in two stages. First to 3 N´m (27 in. lbs.), and then to
7 N´m (62 in. lbs.) torque. Do not pause more than
two minutes between tightening stages as bolts may
lose their ability to retain torque.
(4) Ensure FCA is mounted flush to injection
pump.
(5) Connect electrical connector to FCA.
(6) Start engine and observe for leaks.
FUEL INJECTOR
DESCRIPTION
Six individual, solenoid actuated high-pressure fuel
injectors are used (Fig. 14). The injectors are vertically
mounted into a bored hole in the top of the cylinder
head. This bored hole is located between the intake/
exhaust valves. High-pressure connectors (Fig. 15),
mounted into the side of the cylinder head, connect
each fuel injector to each high-pressure fuel line.
Fig. 13 FUEL CONTROL ACTUATOR
1 - ACTUATOR MOUNTING BOLTS
2 - FCA (FUEL CONTROL ACTUATOR)
3 - ACTUATOR ELECTRICAL CONNECTOR
Fig. 14 FUEL INJECTOR - DIESEL
1 - SOLENOID ELECTRICAL CONNECTOR STUDS
2 - MOUNTING BOLTS
3 - MOUNTING PLATES
4- COPPER SEALING WASHER
5 - INJECTOR TIP
6 - INJECTOR O-RING
7 - INJECTOR ELECTRICAL SOLENOID
DRFUEL INJECTION - DIESEL 14 - 85

OPERATION
High-pressure fuel is supplied from the injection
pump, through a high-pressure fuel line, through a
fuel pressure limiting valve, into a fuel rail, through
high-pressure lines, through steel connectors and
into the solenoid actuated fuel injector. The ECM
actuates the solenoid causing the needle valve to rise
and fuel flows through the spray holes in the nozzle
tip into the combustion chamber.
Each fuel injector is connected to the fuel rail by a
high-pressure fuel line with a steel connector. This
steel connector is positioned into the cylinder head
and sealed with an o-ring. The connectors are sealed
to the high-pressure fuel lines with fittings. The fer-
rule on the end of the high-pressure fuel line pushes
against the steel connector when the fuel line fitting
is torqued into the cylinder head. This torquing force
provides a sealing pressure between both the fuel
line-to-connector and the fuel connector-to-fuel injec-
tor.The fitting torque is very critical.If the fit-
ting is under torqued, the mating surfaces will not
seal and a high-pressure fuel leak will result. If the
fitting is over torqued, the connector and injector will
deform and also cause a high-pressure fuel leak. This
leak will be inside the cylinder head and will not bevisible. The result will be a possible fuel injector
miss-fire and low power.
The fuel injectors use hole type nozzles. High-pres-
sure flows into the side of the injector, the ECM acti-
vates the solenoid causing the injector needle to lift
and fuel to be injected. The clearances in the nozzle
bore are extremely small and any sort of dirt or con-
taminants will cause the injector to stick. Because of
this, it is very important to do a thorough cleaning of
any lines before opening up any fuel system compo-
nent. Always cover or cap any open fuel connections
before a fuel system repair is performed.
Each fuel injector connector tube contains an edge
filter that breaks up small contaminants that enter
the injector. The edge filter uses the injectors pulsat-
ing high-pressure to break up most particles so they
are small enough to pass through the injector.The
edge filters are not a substitute for proper
cleaning and covering of all fuel system compo-
nents during repair.
The bottom of each fuel injector is sealed to the
cylinder head with a1.5mmthick copper shim (gas-
ket). The correct thickness shim must always be re-
installed after removing an injector.
Fuel pressure in the injector circuit decreases after
injection. The injector needle valve is immediately
Fig. 15 HIGH-PRESSURE CONNECTOR
1 - HIGH-PRESSURE CONNECTOR (TO FUEL INJECTOR)
2 - O-RING
3 - CONNECTOR RETAINER4 - FUEL RAIL
5 - HIGH-PRESSURE FUEL LINES
6 - LOCATING PINS
14 - 86 FUEL INJECTION - DIESELDR
FUEL INJECTOR (Continued)

(8) Remove 3 injector rail mounting bolts (Fig. 23).
(9) Remove rail from top of intake manifold.
INSTALLATION
(1) Clean any dirt/debris from top of intake mani-
fold and bottom of fuel rail.
(2) Position fuel rail to top of manifold and install
3 mounting bolts. Tighten 3 bolts to 24 N´m (18 ft.
lbs.) torque.
(3) Install all high-pressure lines to rail. Refer to
Fuel Lines for procedures.
(4) Reposition wiring harness to intake manifold
and install new tie wraps.
(5) Position fuel limiting valve and install banjo
bolt. Tighten bolt to 30 N´m (22 ft. lbs.) torque.
(6) Connect electrical connector to fuel pressure
sensor.
(7) Position 2 positive (+) cables to intake heater
studs. Install 2 nuts.
(8) Connect battery cables to both batteries.
(9) Start engine and check for leaks.
INLET AIR TEMPERATURE
SENSOR/PRESSURE SENSOR
DESCRIPTION
The combination, dual function Inlet Air Tempera-
ture/Pressure Sensor is located on the air cleaner (fil-
ter) cover.
OPERATION
The Inlet Air Temperature/Pressure Sensor is a
combination dual-function sensor. The sensor element
extends into the intake air stream at the top of the
air filter housing. Ambient air temperature as well as
barometric pressure is monitored by this sensor. The
Engine Control Module (ECM) monitors signals from
this sensor.
REMOVAL
The Inlet Air Temperature/Pressure Sensor is
located on the air cleaner cover (Fig. 24).
(1) Disconnect electrical connector at sensor (Fig.
25).
(2) Remove two Torx-type mounting screws.
(3) Remove sensor from air cleaner cover.
(4) Check condition of sensor o-ring (Fig. 26).
INSTALLATION
(1) Check condition of sensor o-ring.
(2) Position sensor into top of air cleaner cover
with a slight twisting action.
(3) Install 2 mounting screws.
(4) Install electrical connector.
Fig. 23 FUEL INJECTOR RAIL
1 - FUEL RAIL MOUNTING BOLTS (3)
2 - INSULATED CLAMPS
3 - FUEL INJECTOR RAIL
Fig. 24 IAT/PRESSURE SENSOR LOCATION - 5.9L
DIESEL
1 - CLIPS
2 - FILTER COVER
3 - FILTER MINDERŸ
4 - INLET AIR TEMPERATURE/ PRESSURE SENSOR
5 - FILTER HOUSING
14 - 90 FUEL INJECTION - DIESELDR
FUEL INJECTOR RAIL (Continued)

TIRE CHAINS
Tire snow chains may be used oncertainmodels.
Refer to the Owner's Manual for more information.
DESCRIPTION - RADIAL ± PLY TIRES
Radial-ply tires improve handling, tread life and
ride quality, and decrease rolling resistance.
Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary. A maximum speed of 50
MPH is recommended while a temporary spare is in
use.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They also
use the same recommended inflation pressures.
The use of oversized tires, either in the front or
rear of the vehicle, can cause vehicle drive train fail-
ure. This could also cause inaccurate wheel speed
signals when the vehicle is equipped with Anti-Lock
Brakes.
The use of tires from different manufactures on the
same vehicle is NOT recommended. The proper tire
pressure should be maintained on all four tires.
DESCRIPTION - TIRE PRESSURE FOR HIGH
SPEEDS
Where speed limits allow the vehicle to be driven at
high speeds, correct tire inflation pressure is very
important. For speeds up to and including 120 km/h (75
mph), tires must be inflated to the pressures shown on
the tire placard. For continuous speeds in excess of 120
km/h (75 mph), tires must be inflated to the maximum
pressure specified on the tire sidewall.
Vehicles loaded to the maximum capacity should not
be driven at continuous speeds above 75 mph (120
km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
DESCRIPTION - REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
It is recommended that tires equivalent to the orig-
inal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehicle.
The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
DESCRIPTION - TIRE INFLATION PRESSURES
Under inflation will cause rapid shoulder wear, tire
flexing, and possible tire failure (Fig. 12).
Over inflation will cause rapid center wear and
loss of the tire's ability to cushion shocks (Fig. 13).
Improper inflation can cause:
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride
²Vehicle drift
For proper tire pressure specification refer to the Tire
Inflation Pressure Chart provided with the vehicles
Fig. 11 Tire Identification
22 - 6 TIRES/WHEELSDR
TIRES (Continued)

verter. The PCM calculates the A/F mixture from the
output of the O2S. A low voltage indicates high oxy-
gen content (lean mixture). A high voltage indicates a
low content of oxygen (rich mixture).
When the upstream O2S detects a lean condition,
there is an abundance of oxygen in the exhaust gas.
A functioning converter would store this oxygen so it
can use it for the oxidation of HC and CO. As the
converter absorbs the oxygen, there will be a lack of
oxygen downstream of the converter. The output of
the downstream O2S will indicate limited activity in
this condition.
As the converter loses the ability to store oxygen,
the condition can be detected from the behavior of
the downstream O2S. When the efficiency drops, no
chemical reaction takes place. This means the con-
centration of oxygen will be the same downstream as
upstream. The output voltage of the downstream
O2S copies the voltage of the upstream sensor. The
only difference is a time lag (seen by the PCM)
between the switching of the O2S's.
To monitor the system, the number of lean-to-rich
switches of upstream and downstream O2S's is
counted. The ratio of downstream switches to
upstream switches is used to determine whether the
catalyst is operating properly. An effective catalyst
will have fewer downstream switches than it has
upstream switches i.e., a ratio closer to zero. For a
totally ineffective catalyst, this ratio will be one-to-
one, indicating that no oxidation occurs in the device.
The system must be monitored so that when cata-
lyst efficiency deteriorates and exhaust emissions
increase to over the legal limit, the MIL will be illu-
minated.
DESCRIPTION - TRIP DEFINITION
The term ªTripº has different meanings depending
on what the circumstances are. If the MIL (Malfunc-
tion Indicator Lamp) is OFF, a Trip is defined as
when the Oxygen Sensor Monitor and the Catalyst
Monitor have been completed in the same drive cycle.
When any Emission DTC is set, the MIL on the
dash is turned ON. When the MIL is ON, it takes 3
good trips to turn the MIL OFF. In this case, it
depends on what type of DTC is set to know what a
ªTripº is.
For the Fuel Monitor or Mis-Fire Monitor (contin-
uous monitor), the vehicle must be operated in the
ªSimilar Condition Windowº for a specified amount of
time to be considered a Good Trip.
If a Non-Contiuous OBDII Monitor fails twice in a
row and turns ON the MIL, re-running that monitor
which previously failed, on the next start-up and
passing the monitor, is considered to be a Good Trip.
These will include the following:
²Oxygen Sensor²Catalyst Monitor
²Purge Flow Monitor
²Leak Detection Pump Monitor (if equipped)
²EGR Monitor (if equipped)
²Oxygen Sensor Heater Monitor
If any other Emission DTC is set (not an OBDII
Monitor), a Good Trip is considered to be when the
Oxygen Sensor Monitor and Catalyst Monitor have
been completed; or 2 Minutes of engine run time if
the Oxygen Sensor Monitor or Catalyst Monitor have
been stopped from running.
It can take up to 2 Failures in a row to turn on the
MIL. After the MIL is ON, it takes 3 Good Trips to
turn the MIL OFF. After the MIL is OFF, the PCM
will self-erase the DTC after 40 Warm-up cycles. A
Warm-up cycle is counted when the ECT (Engine
Coolant Temperature Sensor) has crossed 160ÉF and
has risen by at least 40ÉF since the engine has been
started.
DESCRIPTION - COMPONENT MONITORS
There are several components that will affect vehi-
cle emissions if they malfunction. If one of these com-
ponents malfunctions the Malfunction Indicator
Lamp (MIL) will illuminate.
Some of the component monitors are checking for
proper operation of the part. Electrically operated
components now have input (rationality) and output
(functionality) checks. Previously, a component like
the Throttle Position sensor (TPS) was checked by
the PCM for an open or shorted circuit. If one of
these conditions occurred, a DTC was set. Now there
is a check to ensure that the component is working.
This is done by watching for a TPS indication of a
greater or lesser throttle opening than MAP and
engine rpm indicate. In the case of the TPS, if engine
vacuum is high and engine rpm is 1600 or greater,
and the TPS indicates a large throttle opening, a
DTC will be set. The same applies to low vacuum if
the TPS indicates a small throttle opening.
All open/short circuit checks, or any component
that has an associated limp-in, will set a fault after 1
trip with the malfunction present. Components with-
out an associated limp-in will take two trips to illu-
minate the MIL.
OPERATION
OPERATION
The Powertrain Control Module (PCM) monitors
many different circuits in the fuel injection, ignition,
emission and engine systems. If the PCM senses a
problem with a monitored circuit often enough to
indicate an actual problem, it stores a Diagnostic
Trouble Code (DTC) in the PCM's memory. If the
25 - 4 EMISSIONS CONTROLDR
EMISSIONS CONTROL (Continued)