2006 DODGE RAM SRT-10 engine

INJECTOR - FUEL
DESCRIPTION
An individual fuel injector (1) is used for each individ-
ual cylinder.
OPERATION
FUEL INJECTOR
The top (fuel entry) end of the injector (1) 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, adding it to the air
entering the combustion chamber.
The nozzle (outlet) 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.
The injectors are energized individually in a sequential 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 isenergized. The PCM will adjust injector pulse width based on various inputs it
receives.
Battery voltage is supplied to the injectors through the ASD relay.
The PCM determines injector pulse width based on various inputs.
PCM OUTPUT
The nozzle ends of the injectors are positioned into openings in the intakemanifold 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 sequential 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 isenergized. The PCM will adjust injector pulse width based on various inputs it
receives.

Battery voltage (12 volts +) is supplied to the injectors 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
3.7/4.7/ 5.7L
1. Remove fuel rail. (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL RAIL - REMOVAL)
2. Disconnect clip(s) that retain fuel injector(s) to fuel
rail (2).
8.3L - SRT-10
1. Release fuel system pressure. Refer to Fuel Pres-
sure Release Procedure in this section.
2. Remove the battery cover and disconnect negative
battery cable.
3. Remove the air cleaner assembly, refer to the
Engine/Air Intake System/Air Cleaner Housing for
more information.
4. Disconnect the electrical connector to the MAP
sensor and Coolant Temperature sensor.

12. Remove the fuel injector from the fuel rail.
INSTALLATION
3.7/ 4.7/ 5.7L
1. Install fuel injector(s) into fuel rail assembly and install retainingclip(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 14 - FUEL SYSTEM/FUEL DELIVERY/FUEL RAIL - INSTALLATION)
5. Start engine and check for fuel leaks.
8.3L - SRT-10
1. Install the fuel injectors to the fuel rail.
2. Install fuel rail under throttle body.
3. Apply a light coating of clean engine oiltotheO-ringonthenozzleendofeach injector.
4. Insert fuel injector nozzles into openings in intake manifold. Seat theinjectors in place. Tighten fuel rail bolts to
12 Nꞏm (105 in. lbs.).
5. Attach electrical connectors to fuel injectors.
6. Connect the electrical connector to the MAP sensor and Coolant Temperature sensor.
7. Connect the electrical connector to the TPS and Idle Air Control.
8. Install the wiring harness to the wiring clips under the throttle body.
9. Connect fuel supply tube to fuel rail. Refer to Quick Connect Fittings inthe Fuel Delivery section
10. Install the negative battery cable and install the battery cover.
11. Install the air cleaner assembly, refer to the Engine/Air Intake System/Air Cleaner Housing for more information.
12. Use the DRBIII
scan tool ASD Fuel System Test to pressurize the fuel system. Check for leaks.

RELAY - FUEL PUMP
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 electric 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 operating or the starter motor is
engaged.
REMOVAL
The fuel pump relay is located in the Power Distribu-
tion Center (PDC) (2). 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 con-
nector 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 Distribution Center (PDC). Refer to label on PDC cover for relay loca-
tion.
1. Install relay to PDC.
2. Install cover to PDC.

MOTOR-IAC
DESCRIPTION
3.7L, 4.7L, 5.7L
3.7L:The IAC stepper motor (3) is mounted to the
throttle body. It 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 pas-
sage 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.
4.7L:The IAC stepper motor (3) is mounted to the
throttle body. It 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 pas-
sage 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.
5.7L:A separate IAC motor is not used with the 5.7L
V- 8 e n g i n e .

8.3L - SRT-10
The idle air control motor is mounted at the front right
of the intake manifold.
OPERATION
3.7L V-6/4.7L V-8
A separate IAC motor is not used with the 5.7L V-8 engine.
At idle, engine speed can be increased by retracting 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 diminishing 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 during decel
(keep engine from stalling).
The IAC motor has 4 wires with 4 circuits. Two of the wires are for 12 volts andground to supply electrical current
to the motor windings to operate the stepper motor in one direction. The other2wiresarealsofor12voltsand
ground to supply electrical current to operate the stepper motor in the opposite direction.
To make the IAC go in the opposite direction, the PCM just reverses polarityon both windings. If only 1 wire is
open, the IAC can only be moved 1 step (increment) in either direction. To keeptheIACmotorinpositionwhenno
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 knowsthe position of the pintle. So at the
first key ON, the PCM drives the IAC motor closed, regardless of where it wasbefore. This zeros the counter. From
this point the PCM will back out the IAC motor and keep track of its position again.
When engine rpm is above idle speed, the IAC is used for the following:
Off-idle dashpot (throttle blade will close quickly but idle speed will notstopquickly)
Deceleration air flow control
A/C compressor load control (also opens the passage 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 control 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 thenext 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 stepper 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 accomplished by delaying compressor
operation for approximately 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 eliminate idle-quality changes as loads change. Finally,
the PCM incorporates a
No-Loadengine speed limiter of approximately 1800 - 2000 rpm, when it recognizes that
the TPS is indicating an idle signal and IAC motor cannot maintain engine idle.
A (factory adjusted) set screw is usedto mechanically 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 (3) is located on the
side of the throttle body.
1. Remove air resonator box at throttle body.
2. Disconnect electrical connector from IAC motor.
3. Remove two mounting bolts (screws) (4).
4. Remove IAC motor from throttle body.

4.7L V-8
The Idle Air Control (IAC) motor (3) is located on the
side of the throttle body.
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.
5.7L V-8
The IAC motor is not serviceable on the 5.7L V-8 engine.
8.3L - SRT-10
The IAC motor is inserted into a housing at the front of the intake manifold.The IAC motor and housing are ser-
viced together.
1. Remove housing to manifold screws. Remove IAC motor and housing.
2. Disconnect the electrical connector from IAC motor.