Dodge Ram Truck 1500-2500-3500. Manual — part 1434

INSTALLATION

3.7L/4.7L/5.7L ENGINE

1. Loosely assemble exhaust tailpipe to permit proper

alignment of all parts.

2. Connect the support hangers.

3. Position the exhaust tailpipe for proper clearance

with the underbody parts.

4. Tighten all clamp nuts to 54.2 N·m (40 ft. lbs.)

torque.

5. Check the exhaust system for contact with the

body panels. A minimum of 25.4 mm (1.0 in.) is
required between the exhaust system components
and body/frame parts. Make the necessary adjust-
ments, if needed.

6. Lower the vehicle.

7. Start the engine and inspect for exhaust leaks.

Repair exhaust leaks as necessary.

5.9L DIESEL

1. Install the tailpipe into the muffler.

2. Install the tailpipe hanger rods into the isolators

3. Install the exhaust clamp, align the exhaust sys-

tem, and tighten the clamp 48 N·m (35 ft. lbs.)
torque.

4. Check the exhaust system for contact with the

body panels. A minimum of 25.4 mm (1.0 in.) is
required between the exhaust system components
and body/frame parts. Make the necessary adjust-
ments, if needed.

5. Lower the vehicle.

6. Connect the battery negative cables.

7. Start the engine and inspect for exhaust leaks.

Repair exhaust leaks as necessary.

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EXHAUST SYSTEM

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8.3L ENGINE

1. Position tailpipes (6) into muffler (2).

2. Make sure alignment tang on tailpipes ( 6) fully

seat into alignment slots on muffler (2).

3. Install insulators (5).

4. Check the exhaust system for contact with the

body panels. A minimum of 25.4 mm (1.0 in.) is
required between the exhaust system components
and body/frame parts. Make the necessary adjust-
ments, if needed.

5. Tighten all clamp (4) nuts to 54.2 N·m (40 ft. lbs.)

torque.

6. Lower the vehicle.

7. Start the engine and inspect for exhaust leaks.

Repair exhaust leaks as necessary.

TURBOCHARGER SYSTEM

DIAGNOSIS AND TESTING

TURBOCHARGER BOOST PRESSURE

Low turbocharger boost pressure can cause poor engine performance and driveability concerns. The following pro-
cedure will test the turbocharger boost pressure.

Causes of low boost pressure include the following:

•

Restricted air inlet system

•

Leak in charge air cooler system

•

Restricted/high pressure drop across charge air cooler

•

Damaged turbocharger compressor wheel housing

•

Turbocharger wastegate stuck open

•

Excessive exhaust restriction

Causes of excessively high boost pressure include:

•

Turbocharger wastegate stuck closed

•

Turbocharger wastegate signal line leaking or damaged

•

Damaged wastegate command valve O-rings

•

Wastegate command valve mechanically stuck in actuated position

Several Diagnostic Trouble Codes (DTCs) can be set that will indicate high or low system boost levels. There is a
DTC for circuit faults relating to the electronically controlled wastegate command valve.

(Refer to 11 - EXHAUST SYSTEM/TURBOCHARGER SYSTEM/CHARGE AIR COOLER AND PLUMBING - DIAG-
NOSIS AND TESTING) for diagnosing of low or high boost pressure due to leaks.

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TURBOCHARGER

DESCRIPTION

The turbocharger is an exhaust-driven supercharger
which increases the pressure and density of the air
entering the engine. With the increase of air entering
the engine, more fuel can be injected into the cylin-
ders, which creates more power during combustion.

The turbocharger assembly consists of five (5) major
component systems :

•

Turbine section (1)

•

Compressor section (4)

•

Bearing housing (4)

•

Wastegate

•

Electronically

controlled

wastegate

command

valve

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EXHAUST SYSTEM

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OPERATION

Exhaust gas pressure and energy drive the turbine,
which in turn drives a centrifugal compressor that
compresses the inlet air, and forces the air into the
engine through the charge air cooler and plumbing.
Since heat is a by-product of this compression, the air
must pass through a charge air cooler to cool the
incoming air and maintain power and efficiency.

Increasing air flow to the engine provides:

•

Improved engine performance

•

Lower exhaust smoke density

•

Improved operating economy

•

Altitude compensation

•

Noise reduction.

The turbocharger also uses a wastegate , which reg-
ulates intake manifold air pressure and prevents over
boosting at high engine speeds and loads. When the
wastegate valve is closed, all of the exhaust gases
flow through the turbine wheel. As the boost pressure
(compressor outlet ) increases, the boost pressure is
fed to the wastegate actuator via a wastegate signal
line. When sufficient boost pressure is achieved, the
boost pressure applied to the wastegate diaphragm
overcomes spring pressure and moves an actuator
rod to open an exhaust bypass valve. When exhaust
gas is diverted from the turbine wheel, turbine shaft
speed is limited which reduces compressor wheel
speed, thereby limiting boost pressure.

The turbocharger also includes an additional compo-
nent, an Electronically Controlled Wastegate Com-
mand Valve, to control boost pressure. The command
valve is located on the turbocharger compressor housing.

When the command valve is not actuated (no current supplied to the valve), a passage in the valve allows the
wastegate signal line to be supplied with boost pressure. This allows boost pressure to be mechanically regulated
by the wastegate as in a conventional wastegated system.

When the engine control module (ECM) provides a pulse width modulated (PWM) signal to the command valve,
boost pressure is bypassed away from the wastegate signal line through a drilling in the turbocharger compressor
housing. The internal drilling bleeds boost pressure back to the turbocharger compressor inlet (low pressure). Actu-
ating the command valve and bypassing the boost pressure signal to the wastegate allows the engine to operate at
a higher boost than would be achieved if the wastegate were allowed to operate normally.

Actuating the command valve does not increase boost pressure if the boost pressure is below the wastegate actua-
tor setting. With the command valve actuated, maximum boost pressure at a given operating condition will vary
based on ambient air pressure and temperature.

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