3rd Gen Engine and Drivetrain -> 2003-2007 5.9 liter Engine and drivetrain discussion only. PLEASE, NO HIGH PERFORMANCE DISCUSSION!

Cummins CP3 injection system

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Old Oct 11, 2007 | 02:27 PM
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Cummins CP3 injection system

I've edited excerpts from the manual for scope and clarity - read it if you will, ignore it if you must.....................

FUEL SYSTEM
A Robert Bosch high-pressure fuel injection pump is used. The pump is attached to the back of the timing gear housing


DESCRIPTION
The fuel system on the 5.9L Common Rail Diesel Engine uses a rotary mechanical fuel injection pump and an Electronic Control Module (ECM) and is a drive-by-wire system, meaning there is no physical throttle cable.
The fuel delivery system consists of the:
- Accelerator pedal position-sensor module
- Air cleaner housing\element
- Fuel filter\water separator
- Fuel temperature sensor
- Fuel heater
- Fuel rail pressure relief valve
- Fuel rail pressure sensor
- Fuel injection pump
- Fuel injectors
- Fuel tank
- Fuel tank filler\vent tube assembly
- Fuel tank filler-tube cap
- Fuel tank module containing the electric lift pump, roll-over valve and a fuel gauge sending unit (fuel level sensor).
- Fuel tubing\lines\hoses
- High-pressure fuel injector lines
- Low-pressure fuel supply and return lines
- Low-pressure fuel return line
- Overflow valve
- Quantity control Fuel Control Actuator valve
- Quick-connect fittings
- Water sensor\drain module


FUEL INJECTION PUMP
The Cummins 5.9L CRD uses the Bosch CP3 injection pump, used also on the DMax 6.6L V8 CRD and the Jeep 2.8L CRD

DESCRIPTION
A radial, 3-piston pump, with a gearotor pump attached to the back cover, is used as the high-pressure
pump for common-rail fuel pressure generation - it is capable of pressures between 300-1600 bar (4351-23206 psi) .
A spring-loaded Cascade Overflow Valve regulates internal housing pressure
Regulated internal housing pressure is oem-specific
The pump shaft is driven by the timing belt at 1:1 ratio to the crankshaft.
Fuel pressure is generated independently of the injection process.
A Fuel Control Actuator valve regulates injection pressure
The pump is lubricated by the pumped Diesel fuel and is not responsible for fuel injection timing.

OPERATION

GEAROTOR PUMP

DESCRIPTION
The gearotor pump has two functions
- draws fuel from the fuel supply
- increases fuel pressure for regulation to housing pressure required for internal lubrication and supplying the high-pressure injection pump


OPERATION
This fuel system uses a gearotor supply-pump attached to the rear of the high-pressure pump. This medium-pressure fuel pump is driven by the end of the high-pressure pump shaft, and can generate 20" vacuum at the fuel inlet at high rpm.
The gearotor pump is supplied fuel from the lift pump in the fuel tank through the fuel manager\filter.

The outlet of the gearotor pump provides pressurized fuel to a branched circuit internal to the high-pressure
pump flange, which supplies both the Fuel Control Actuator solenoid valve and the Cascade Overflow Valve\regulator. Because the gearotor pump increases fuel flow and pressure as engine rpm increases, the pressure and flow is regulated by the COV.

The COV and gearotor supply-pump are not serviced independently of the high-pressure pump.

CASCADE OVERFLOW VALVE

DESCRIPTION
The COV is located on the front cover of the high pressure pump.
The Cascade Overflow Valve has three functions:
- regulation of lubrication fuel to the internal moving parts of the high-pressure pump
- regulation of the fuel pressure being supplied to the Fuel Control Actuator solenoid valve
- return excess fuel to the fuel tank
This regulated internal pressure is known as housing pressure, and is determined by engine displacement and power requirements - the 5.9L CRD requires 12.4 bar (180 psi)
For comparison, the 2.8L 4-cyl Jeep CRD requires 5bar (73psi)

OPERATION
The COV has a spring-loaded center spool-piece that has a drilled channel with three passages: one for initial low-pressure lubrication, one for lubrication at housing-pressure , and one for overflow. The valve is operated in three stages based on the level of pressure at the inlet.

Stage 1
When the fuel pressure entering the tip of the COV is between 0 and 3 bar (43psi), pressure is too low to overcome
regulator spring tension and fuel flows through the center channel, only . This passage always allows fuel flow through to the pump center-ring and lubricates the pump bushings and internal moving parts. This circuit also allows air to bleed during initial cranking and returns the air to the fuel tank.
The COV is in Stage 1 during cranking, only.

Stage 2
When the fuel entering the COV exceeds 5bar (73psi), but is less than 12.4bar (180psi), the spool-piece
moves against spring tension aligning a second passage for lubrication purposes.
Stage 2 can be reached during cranking and initial start up.


Stage 3
When fuel pressure exceeds 12.4bar (180psi), the spool-piece aligns with the overflow passage. This stage
relieves the pressure into an overflow circuit that sends the fuel back to the inlet side of the gearotor pump, thus limiting maximum fuel pressure to 1241bar (180psi).
Lubrication fuel continues to flow through all channeled passages during this stage.
Excess fuel is sent back to the fuel tank through the fuel-return circuit
Stage 3 is reached at over-pressure

FUEL CONTROL ACTUATOR

DESCRIPTION
The Fuel Control Actuator solenoid valve is located on the back of the front cover of the high-pressure pump. The solenoid is pulse-width modulated by the ECM and meters the amount of fuel that flows into the high-pressure elements inside the high-pressure pump.
The solenoid is inactive during the first 30 seconds after IGNition switch is initially keyed to ON position to allow maximum fuel pressure to the fuel rail during cranking and start up. ECM assumes FCA valve control when CPS signal and rail pressure are within acceptable limits

OPERATION
The Fuel Control Actuator solenoid valve is a pulse-width modulated valve that controls the amount of fuel sent or delayed to the high-pressure pump elements inside the high-pressure pump. The ECM determines the fuel pressure set point based on engine sensor and rail-pressure inputs. If the actual fuel-rail pressure is too low, the ECM commands the solenoid to allow more fuel to flow to the high-pressure pump. This minimizes the difference between the actual fuel-rail pressure reading and the set point. The ECM will also operate the solenoid to delay fuel, reducing flow-rate, if the fuel-rail pressure becomes too high.
The FCA valve is commanded open by the ECM to allow the high-pressure pump to build maximum pressure
(1600bar, 23,206psi).
Thus, rail fuel-pressure can be increased or decreased independent of engine speed


High Pressure Pumping Plungers
The FQS valve supplies three high pressure pumping chambers. The pumping chambers have one-way
inlet valves that allow fuel to flow into the chambers. The valves then close as the fuel is compressed,
causing the high pressure fuel to overcome a spring-loaded ball-and-seat outlet valve.
All three pumping chambers are tied together in one circuit internal to the pump and provide high pressure fuel
between 300bar (4351psi) and 1600bar (23,206psi) through a steel line to the fuel rail.
The pump is driven at 1:1 engine speed and is not responsible for injection timing.
Pump function is to provide fuel at high-pressure, while the ECM controls injection pressure and timing.


FUEL RAIL

DESCRIPTION
The fuel rail is mounted to the cylinder-head cover\intake manifold. The rail distributes regulated high-pressure fuel equally to the fuel injectors.
A pressure sensor is screwed into the rail so ECM can read and regulate system pressure.
A pressure relief valve is screwed into the rear of the fuel rail to allow overflow return to the fuel tank.

OPERATION
The fuel rail stores the fuel for the injectors at high pressure. At the same time, the pressure oscillations which are
generated due to the high-pressure pump delivery and the injection of fuel are dampened by rail volume.
The fuel rail is common to all cylinders, hence it’s name "common rail". Even when large quantities of fuel are
extracted, the fuel rail maintains a constant inner pressure. This ensures that injection pressure remains constant
from the instant the injector opens to the end of the injection event.

PRESSURE LIMITING VALVE

DESCRIPTION
The fuel pressure limiting valve is located on the top of the fuel rail.

OPERATION
Fuel pressure at the fuel rail is monitored by the fuel rail pressure sensor. If fuel pressure becomes excessive, the
pressure limiting valve opens and vents excess pressure into the fuel drain circuit.
.

FUEL LINES

DESCRIPTION

LOW-PRESSURE FUEL LINES
All fuel lines up to the fuel injection pump are considered low-pressure. This includes the fuel lines from the fuel
tank module to the inlet of the high-pressure fuel injection pump. The fuel-return lines and the fuel-drain lines are also considered low-pressure lines.
High-pressure lines are used between the fuel injection pump and the fuel injectors

HIGH PRESSURE FUEL LINES
High-pressure fuel lines are used between the high pressure fuel injection pump and the fuel rail, and between
the fuel rail and fuel injectors
All other fuel lines are considered low-pressure lines.

OPERATION - HIGH PRESSURE FUEL LINES
High-pressure fuel lines deliver fuel under extremely high pressure - between 300-1600 bar (4351-23206 psi) - from the high-pressure pump to the rail to the fuel injectors. The lines expand and contract from the high-pressure fuel pulses generated during the injection process, which can delay the injection event - ECM compensates for that based on component specs
All high-pressure fuel lines between the rail and the injectors are of the same length and inside diameter to ensure equal-duration injection events, cylinder to cylinder.
Correct high-pressure fuel line usage and installation is critical to smooth engine operation.


FUEL MANAGER\FILTER

FUEL FILTER / WATER SEPARATOR

DESCRIPTION
The fuel filter/water separator assembly is located on the left rear side of the engine. It incorporates
the fuel temperature sensor, fuel heater and a Water-In-Fuel (WIF) sensor.
Only the fuel filter cannister and the WIF sensor are serviced separately. The top-loaded fuel filter has a 3-micron element and the cap
tightens clockwise to the housing.

OPERATION
The fuel filter/water separator protects the high pressure fuel injection pump by removing water and contaminants
from the fuel with a 3-micron filter element. 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 cannister for draining.

A Water-In-Fuel (WIF) sensor is attached to the fuel filter cannister and is serviced separately.

The fuel heater and fuel temperature sensor are in a thermoplastic module inside the fuel manager head - it is not serviced separately from the head.


WATER IN FUEL SENSOR

DESCRIPTION
The WIF sensor is attached to the bottom of the fuel filter/water separator cannister. The sensor also has a drain channel and provision for adapting a drain hose.
OPERATION
The sensor varies an input to the ECM, allowing it to sense water in the fuel filter/water separator.
As the water content in the filter/separator increases, the resistance across the WIF sensor decreases. This
decrease in resistance is measured by the ECM and compared to a calibrated standard value. If the resistance
drops to a value between 30 and 40 kohms, the ECM will activate the Water-In-Fuel warning lamp. This all occurs when the IGNition key is initially switched to ON position


FUEL HEATER

DESCRIPTION
The fuel heater is used to prevent diesel fuel from waxing and plugging the fuel filter during cold weather operation.
The fuel heater is located in the fuel heater module, next to the fuel temperature sensor - the module is internal to the fuel manager head.
On temperature is 7°C (45° F), off temperature is 29°C (85° F).

OPERATION
The element inside the heater assembly is made of a Positive Temperature Coefficient (PTC) material, and has
power applied to it by the fuel heater relay anytime the ignition key is in the ON position. PTC material has a high
resistance to current flow when its temperature is high, which means that it will not generate heat when the
temperature is above a certain value. When the temperature is below 7°C (45° F), the resistance of the PTC element
is lowered, and allows current to flow through the fuel heater element warming the fuel. When the temperature is
above 29°C (85° F), the PTC element’s resistance rises, and current flow through the heater element stops .

Fused voltage to operate the fuel heater is supplied from the Ign switch, through the fuel heater relay, when the ECM senses the IGNition (key) switch is ON.

Sensed temperature allows full heating only when the temperature drops below 7°C (45° F) - element should not produce full heat on an 18.3°C (65° F) day, for example
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Old Oct 11, 2007 | 02:32 PM
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Continued....................


ELECTRIC FUEL LIFT PUMP

ELECTRIC LIFT PUMP

DESCRIPTION
The under-hood Fuse Center contains a fuse and relay for an electric lift pump.
Relayed power is supplied to the pump, which is mounted in the fuel tank

OPERATION
Fused power to the relay is supplied when the IGN switch is in the ON position.
ECM controls the relay in two modes, prime and run - a safety feature helps prevent fire in event of accident or other emergency

At power-ON, during WTS, ECM closes the relay to prime the low-pressure fuel system to the Inj Pump - if ECM does not sense pulses from the Crank Position Sensor within 15 seconds, the relay is powered down - relay is powered up again when CPS senses crankshaft rotation, indicating START in progress
Power is maintained until crankshaft stops, which is a saftey feature, or when IGN is switched OFF
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Old Oct 11, 2007 | 02:57 PM
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From: WV Panhandle (east)
Very good, thanks.
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Old Oct 14, 2007 | 06:32 AM
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From: texas
Ok - it's edited and correct for Cummins service
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Old Oct 14, 2007 | 08:16 AM
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From: NW Arkansas
It mentions a 3 micron fuel filter. Where do you get it?
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Old Oct 14, 2007 | 06:52 PM
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WOW,Cummins theory 1O1,thanks I will have to get myself educated.
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Old Oct 14, 2007 | 09:40 PM
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From: Auburn WA.
Originally Posted by KWKING
WOW,Cummins theory 1O1,thanks I will have to get myself educated.
X2 great info, I pasted it into a word.doc will be refering to it for quite some time.
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Old Nov 8, 2007 | 01:15 AM
  #8  
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From: texas
Check back occasionally - I edit it as I get updated info
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Old Nov 18, 2007 | 12:29 AM
  #9  
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From: texas
The CP3 Inj Pump has a built-in gearotor-style lift pump, driven by the pump shaft - it will develop 20" vacuum at higer rpm, and is designed to pull fuel from the tank thru a filter.

The '03-'04 trucks have an additional Carter-style rotary lift pump mounted on the fuel manager head - those are not flow-thru when fail type, so the CP3 cannot pull fuel from the tank as the electric pump fails - this will leave you on the side of the road, even tho the CP3 could get you home

The '05-up trucks have an in-tank electric lift pump that runs at a constant 9psi - it flashes toward 30psi at key-on, then settles back to 9psi as the CP3 bypass begins to function - it is a vane-type flow-thru when fail pump, designed to run in Diesel fuel, so the CP3 can draw fuel from the tank if the electric pump fails - this setup will not leave you stranded on the road, dead.

DCX has a conversion kit to upgrade the '03-'04 systems

If you go with an aftermarket type lift pump, make sure it is flow-thru when failed type, so the CP3 can do it's job.
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Old Nov 18, 2007 | 05:15 AM
  #10  
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From: Pattonville, Texas
Anyone have smaller diameter CP3 pulleys?
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Old Nov 18, 2007 | 07:03 AM
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From: Ila georgia
Bosch told me last year 5 micron filter was needed.Dodge did a 10! Then Dodge went to a 7 micron and now Bosch says 3 micron.Baldwin makes a 5 micron.Eaither way we still get the short end of the correct filter unless using a aftermarket system which should not fall on the owners shoulders.
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Old Nov 18, 2007 | 08:28 AM
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From: texas
Bosch actualy recommends a 2 micron filter for the CP3 - dunno if fleetguard builds one for the Dodge filter manager, but seems like they should have to comply with Bosch specs
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Old Nov 18, 2007 | 08:37 AM
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From: Ila georgia
I talked to a Bosch engineer last year in R&D.He stated 5 micron in all HPCR systems they built.Where did you get the info a 2 micron? Chrysler never complied with the micron rating set down by Bosch from the introduction of 3rd generation trucks.
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Old Nov 21, 2007 | 08:36 AM
  #14  
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Hmmmm - saw that 2 micron spec somewhere in my quest for CP3 secrets - lemme see if I can figger out the where and when, and I'll get back with ya, either way, go or no go..................
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Old Nov 21, 2007 | 09:35 AM
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From: Texas
so will a stock lift pump handle an auxiliary 2 mic filter?
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