TheDieselStop.Com is a source of information, discussion, and help pertaining to the full line of Ford trucks, SUVs, and vans with International diesels. We cover everything from the original F-250s with 6.9L diesels all the way up to the newest 2008 Super-Duty trucks with the new 6.4L Power Stroke engine.
Part 3 of 6 in a series of articles outlining the Features, Descriptions, Unique Service Procedures, and General Diagnostics of the 6.0L DIT Power Stroke
From International Truck & Engine Corporation Publication
6.0 DIT Power Stroke
Air Management System
Air Management System Features
The air management system is made up of the air filter, turbocharger, charge
air cooler, intake manifold, and the EGR system.
Air enters the system through the air filter where particles are removed
from the air. The air filter has a filter minder on it to warn the
operator of a restricted air filter.
After the air is filtered, the mass of the air and temperature is measured
by the mass air flow sensor (MAF).
The filtered air is then directed past the crankcase ventilation system
where crankcase vapors and fresh air are mixed.
After mixing with crankcase vapors the fresh air mixture is drawn into the
turbocharger compressor where it is compressed and sent to the charge air cooler
The CAC condenses the air by cooling it then the air returns to the engine
through the intake manifold.
There us a throttle body on the intake manifold. The throttle body may
or may not have a throttle plate. For 2003.25 the throttle plate will not
be active in the PCM strategy.
The intake manifold directs the air to the intake ports of the cylinder
The burned air fuel mixture is pushed out of the cylinder into the exhaust
manifold which collects the exhaust gases and routes them to the turbocharger
The exhaust up pipe, connected to the passenger side exhaust manifold has a
passage that connects it to the exhaust gas recirculation (EGR) cooler.
The exhaust gasses, cooled by the EGR cooler are sent to the EGR valve in
the intake manifold.
The EGR valve controls the flow of exhaust gasses into the intake system
where the gasses are mixed with intake air to reduce NOx (Nitrogen Oxide)
emissions and noise.
The hot and expanding exhaust gasses that are routed to the turbocharger
turbine, spin the turbine wheel through flow and expansion. The spinning
turbine wheel in turn spins the compressor wheel via a common shaft.
Air Filter / Filter Minder
The air filter is located on the drivers side of the engine compartment
between the battery and the radiator.
A filter minder, device used to measure filter restriction, is located on
the back of the air filter housing.
Fresh air, from the drivers side fender and the grill area, is drawn into
the air filter and particulates are removed from the air before going to the
Air Filter Element
The new air filter element is made into the air filter housing. When
replacing the filter, the entire housing will have to be replaced.
The air filter is capable of holding 1600 grams of particulates before
The filter element is a honeycomb design.
Charge Air Cooler
The charge air cooler is located in the front of the radiator.
It is an air-to-air cooler designed to lower the temperature of the air
coming out of the turbocharger outlet before entering the intake manifold.
The turbocharger for the 6.0L Power Stroke engine is designed to
provide boost control at low and high speeds for improved throttle response.
The Variable Geometry Turbocharger (VGT) is electronically controlled and
The VGT may also be referred to as EVRT.
When the vanes of the turbocharger are closed, the engine will have a higher
exhaust back pressure and create more heat which will in turn warm the engine
faster in cold ambient conditions.
The compressor on the VGT is similar to the compressor on a conventional
The compressor wheel is connected to the turbine via a common shaft.
The VGT uses a turbine wheel that is similar to a conventional turbocharger
but the turbine housing has changed.
The turbine housing contains vanes that control the effective size of the
housing. These vanes are hydraulically actuated and electronically
VGT Control Valve
The VGT control valve is commanded by the PCM, based on engine speed and
load. The magnetic field generated by this signal moves a shaft in the
control valve. This movement meters engine oil through the valve to either
side of the piston. This design feature reacts quickly to changes in
demand based on driving conditions. When one side of the piston is
pressurized, the opposite side is vented.
Depending on which side of the piston is pressurized, the vanes either open
or close. A cam follower at the end of the valve assembly provides
feedback to the valve allowing it to reach a neutral position during times the
vanes are not commanded to move.
When the VGTCV is commanded to the full open position, low or no duty cycle,
oil from the oil supply line is directed to the open side of the actuator
Oil on the closed side of the piston is then directed through the actuator
piston, back to the VGTCV, and then to drain.
Note: If the VGTCV is disconnected the valve will default to the open
Once the desired turbocharger vane position is obtained, the VGTCV goes to a
neutral position and both the open and closed sides of the actuator piston is
When the VGTCV is commanded to the full closed position, high duty cycle,
oil from the oil supply line is directed through the actuator piston to the
closed side of the piston.
Oil on the open side of the piston is directed back to the VGTCV and then to
VGT Turbine Vanes Closed
During engine operation at low engine speeds and load, little energy is
available from the exhaust to generate boost. In order to maximize the use
of the energy that is available, the vanes are closed. In doing so, the
exhaust gas is accelerated between the vanes and across the turbine wheel.
In general, this allows the turbocharger to behave as a smaller turbocharger
than it actually is.
Closing the vanes also increases the back pressure in the exhaust manifold
which is used to drive the exhaust gas through the EGR cooler and valve into the
intake manifold. This is also the position for cold ambient warm-up.
VGT Turbine Vanes Partially Closed
During engine operation at moderate engine speeds and load, the vanes are
commanded partially open.
The vanes are set to this intermediate position to supply the correct amount
of boost to the engine for optimal combustion as well as providing the necessary
back pressure to drive EGR.
Note: The VGT control valve piston is coupled to the vanes through a
shaft and the unison ring.
VGT Turbine Vanes Open
During engine operation at high engine speeds and load, there is a great
deal of energy available in the exhaust.
Excessive boost under high speed, high load conditions can negatively affect
component durability, therefore the vanes are commanded open preventing
Essentially, this allows the turbocharger to act as a large turbocharger.
The PCM-controlled EGR (Exhaust Gas Recirculation) valve adds cooled exhaust
gasses to the intake manifold to reduce NOx emissions.
The EGR valve is opened during steady state throttle positions when exhaust
back pressures are higher then intake manifold pressures (boost).
The EGR valve has two valves connected by a common shaft.
Cooled exhaust gases come to the center of the valve through a passage in
the intake manifold.
When the valves open, they allow exhaust gasses to flow into the intake air
stream from the top and bottom of the passage.
The EGR cooler is a coolant to air heat exchanger that is used to cool the
exhaust gasses before they are sent to the EGR valve.
The exhaust gasses are routed into the EGR cooler from the exhaust up pipes
at the rear of the engine.
The exhaust gasses are cooled by passing through metal tubes that are
surrounded by engine coolant. Depending on conditions, the temperature
drop across the cooler could be as much as 700°F.
The cooled gasses are then routed to the EGR valve that is mounted in the
All 2003.25 6.0L Power Stroke engines are equipped with a throttle
Some early versions also have a throttle plate in the throttle body.
Later versions will retain the throttle body but not the throttle plate.
The throttle was designed to assist with EGR operation but later was
The PCM software for controlling the throttle body was not added and the
plate was removed.
The throttle body may become operational for the 2004 model year.
Note: All engines have the wiring plugged into the throttle body and
position sensor even if the throttle plate is not present.
The intake manifold on the 6.0L Power Stroke is made of aluminum and directs
the flow of air to the intake ports in the cylinder heads.
The intake manifold provides a path for coolant from the EGR cooler to the
There is a passage for EGR gasses to go to the EGR valve where they mix with
compressed intake air.
The manifold absolute pressure sensor (MAP) port and the intake air
temperature 2 (IAT2) sensor are both mounted in the intake manifold.
The passage at the rear of the manifold is to equalize pressure on both
sides of the manifold.
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