2002 CHRYSLER CARAVAN fuel pump

FUEL INJECTION
OPERATION
OPERATION - INJECTION SYSTEM
All engines used in this section have a sequential
Multi-Port Electronic Fuel Injection system. The MPI
system is computer regulated and provides precise
air/fuel ratios for all driving conditions. The Power-
train Control Module (PCM) operates the fuel injec-
tion system.
The PCM regulates:
²Ignition timing
²Air/fuel ratio
²Emission control devices
²Cooling fan
²Charging system
²Idle speed
²Vehicle speed control
Various sensors provide the inputs necessary for
the PCM to correctly operate these systems. In addi-
tion to the sensors, various switches also provide
inputs to the PCM.
The PCM can adapt its programming to meet
changing operating conditions.
Fuel is injected into the intake port above the
intake valve in precise metered amounts through
electrically operated injectors. The PCM fires the
injectors in a specific sequence. Under most operat-
ing conditions, the PCM maintains an air fuel ratio
of 14.7 parts air to 1 part fuel by constantly adjust-
ing injector pulse width. Injector pulse width is the
length of time the injector is open.
The PCM adjusts injector pulse width by opening
and closing the ground path to the injector. Engine
RPM (speed) and manifold absolute pressure (air
density) are theprimaryinputs that determine
injector pulse width.
OPERATION - MODES OF OPERATION
As input signals to the PCM change, the PCM
adjusts its response to output devices. For example,
the PCM must calculate a different injector pulse
width and ignition timing for idle than it does for
Wide Open Throttle (WOT). There are several differ-
ent modes of operation that determine how the PCM
responds to the various input signals.
There are two different areas of operation, OPEN
LOOP and CLOSED LOOP.
During OPEN LOOP modes the PCM receives
input signals and responds according to preset PCM
programming. Inputs from the upstream and down-
stream heated oxygen sensors are not monitored dur-
ing OPEN LOOP modes, except for heated oxygensensor diagnostics (they are checked for shorted con-
ditions at all times).
During CLOSED LOOP modes the PCM monitors
the inputs from the upstream and downstream
heated oxygen sensors. The upstream heated oxygen
sensor input tells the PCM if the calculated injector
pulse width resulted in the ideal air-fuel ratio of 14.7
to one. By monitoring the exhaust oxygen content
through the upstream heated oxygen sensor, the
PCM can fine tune injector pulse width. Fine tuning
injector pulse width allows the PCM to achieve opti-
mum fuel economy combined with low emissions.
For the PCM to enter CLOSED LOOP operation,
the following must occur:
(1) Engine coolant temperature must be over 35ÉF.
²If the coolant is over 35ÉF the PCM will wait 38
seconds.
²If the coolant is over 50ÉF the PCM will wait 15
seconds.
²If the coolant is over 167ÉF the PCM will wait 3
seconds.
(2) For other temperatures the PCM will interpo-
late the correct waiting time.
(3) O2 sensor must read either greater than 0.745
volts or less than 0.29 volt.
(4) The multi-port fuel injection systems has the
following modes of operation:
²Ignition switch ON (Zero RPM)
²Engine start-up
²Engine warm-up
²Cruise
²Idle
²Acceleration
²Deceleration
²Wide Open Throttle
²Ignition switch OFF
(5) The engine start-up (crank), engine warm-up,
deceleration with fuel shutoff and wide open throttle
modes are OPEN LOOP modes. Under most operat-
ing conditions, the acceleration, deceleration (with
A/C on), idle and cruise modes,with the engine at
operating temperatureare CLOSED LOOP modes.
IGNITION SWITCH ON (ZERO RPM) MODE
When the ignition switch activates the fuel injec-
tion system, the following actions occur:
²The PCM monitors the engine coolant tempera-
ture sensor and throttle position sensor input. The
PCM determines basic fuel injector pulse width from
this input.
²The PCM determines atmospheric air pressure
from the MAP sensor input to modify injector pulse
width.
When the key is in the ON position and the engine
is not running (zero rpm), the Auto Shutdown (ASD)
and fuel pump relays de-energize after approximately
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1 second. Therefore, battery voltage is not supplied to
the fuel pump, ignition coil, fuel injectors and heated
oxygen sensors.
ENGINE START-UP MODE
This is an OPEN LOOP mode. If the vehicle is in
park or neutral (automatic transaxles) or the clutch
pedal is depressed (manual transaxles) the ignition
switch energizes the starter relay. The following
actions occur when the starter motor is engaged.
²If the PCM receives the camshaft position sensor
and crankshaft position sensor signals, it energizes
the Auto Shutdown (ASD) relay and fuel pump relay.
If the PCM does not receive both signals within
approximately one second, it will not energize the
ASD relay and fuel pump relay. The ASD and fuel
pump relays supply battery voltage to the fuel pump,
fuel injectors, ignition coil, (EGR solenoid and PCV
heater if equipped) and heated oxygen sensors.
²The PCM energizes the injectors (on the 69É
degree falling edge) for a calculated pulse width until
it determines crankshaft position from the camshaft
position sensor and crankshaft position sensor sig-
nals. The PCM determines crankshaft position within
1 engine revolution.
²After determining crankshaft position, the PCM
begins energizing the injectors in sequence. It adjusts
injector pulse width and controls injector synchroni-
zation by turning the individual ground paths to the
injectors On and Off.
²When the engine idles within  64 RPM of its
target RPM, the PCM compares current MAP sensor
value with the atmospheric pressure value received
during the Ignition Switch On (zero RPM) mode.
Once the ASD and fuel pump relays have been
energized, the PCM determines injector pulse width
based on the following:
²MAP
²Engine RPM
²Battery voltage
²Engine coolant temperature
²Inlet/Intake air temperature (IAT)
²Throttle position
²The number of engine revolutions since cranking
was initiated
During Start-up the PCM maintains ignition tim-
ing at 9É BTDC.
ENGINE WARM-UP MODE
This is an OPEN LOOP mode. The following inputs
are received by the PCM:
²Manifold Absolute Pressure (MAP)
²Crankshaft position (engine speed)
²Engine coolant temperature
²Inlet/Intake air temperature (IAT)
²Camshaft position²Knock sensor
²Throttle position
²A/C switch
²Battery voltage
²Vehicle speed
²Speed control
²O2 sensors
The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.
The PCM adjusts ignition timing and engine idle
speed. Engine idle speed is adjusted through the idle
air control motor.
CRUISE OR IDLE MODE
When the engine is at operating temperature this
is a CLOSED LOOP mode. During cruising or idle
the following inputs are received by the PCM:
²Manifold absolute pressure
²Crankshaft position (engine speed)
²Inlet/Intake air temperature
²Engine coolant temperature
²Camshaft position
²Knock sensor
²Throttle position
²Exhaust gas oxygen content
²A/C control positions
²Battery voltage
²Vehicle speed
The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.
The PCM adjusts engine idle speed and ignition
timing. The PCM adjusts the air/fuel ratio according
to the oxygen content in the exhaust gas (measured
by the upstream and downstream heated oxygen sen-
sor).
The PCM monitors for engine misfire. During
active misfire and depending on the severity, the
PCM either continuously illuminates or flashes the
malfunction indicator lamp (Check Engine light on
instrument panel). Also, the PCM stores an engine
misfire DTC in memory, if 2nd trip with fault.
The PCM performs several diagnostic routines.
They include:
²Oxygen sensor monitor
²Downstream heated oxygen sensor diagnostics
during open loop operation (except for shorted)
²Fuel system monitor
²EGR monitor (if equipped)
²Purge system monitor
²Catalyst efficiency monitor
²All inputs monitored for proper voltage range,
rationality.
²All monitored components (refer to the Emission
section for On-Board Diagnostics).
14 - 18 FUEL INJECTIONRS
FUEL INJECTION (Continued)
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FUEL PUMP RELAY
DESCRIPTION
The fuel pump relay is located in the PDC. The
inside top of the PDC cover has a label showing relay
and fuse location.
OPERATION
The fuel pump relay supplies battery voltage to the
fuel pump. A buss bar in the Power Distribution Cen-
ter (PDC) supplies voltage to the solenoid side and
contact side of the relay. The fuel pump relay power
circuit contains a fuse between the buss bar in the
PDC and the relay. The fuse is located in the PDC.
Refer to the Wiring Diagrams for circuit information.
The PCM controls the fuel pump relay by switch-
ing the ground path for the solenoid side of the relay
on and off. The PCM turns the ground path off when
the ignition switch is in the Off position. When the
ignition switch is in the On position, the PCM ener-
gizes the fuel pump. If the crankshaft position sensor
does not detect engine rotation, the PCM de-ener-
gizes the relay after approximately one second.
IDLE AIR CONTROL MOTOR
DESCRIPTION
The idle air control motor is mounted on the throt-
tle body. The PCM operates the idle air control motor
(Fig. 14) or (Fig. 15).
OPERATION
The PCM adjusts engine idle speed through the
idle air control motor to compensate for engine load,
coolant temperature or barometric pressure changes.
The throttle body has an air bypass passage that
provides air for the engine during closed throttle idle.
The idle air control motor pintle protrudes into the
air bypass passage and regulates air flow through it.
The PCM adjusts engine idle speed by moving the
IAC motor pintle in and out of the bypass passage. The
adjustments are based on inputs the PCM receives.
The inputs are from the throttle position sensor, crank-
shaft position sensor, coolant temperature sensor, MAP
sensor, vehicle speed sensor and various switch opera-
tions (brake, park/neutral, air conditioning).
When engine rpm is above idle speed, the IAC is
used for the following functions:
²Off-idle dashpot
²Deceleration air flow control
²A/C compressor load control (also opens the pas-
sage slightly before the compressor is engaged so
that the engine rpm does not dip down when the
compressor engages)
Target Idle
Target idle is determined by the following inputs:
²Gear position
²ECT Sensor
²Battery voltage
²Ambient/Battery Temperature Sensor
²VSS
²TPS
²MAP Sensor
Fig. 14 TPS/IAC 2.4L
1 - Idle Air Control Motor
2 - Throttle Position Sensor
Fig. 15 TPS/IAC 3.3/3.8L
1 - Idle Air Control Motor
2 - Throttle Position Sensor
RSFUEL INJECTION14-27
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FUEL SYSTEM
TABLE OF CONTENTS
page page
FUEL SYSTEM 2.5L TURBO DIESEL
DESCRIPTION - DIESEL FUEL DELIVERY
SYSTEM.............................1
WARNING - HIGH FUEL SYSTEM PRESSURE . . 1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AIR IN FUEL
SYSTEM.............................1
DIAGNOSIS AND TESTING - FUEL SUPPLY
RESTRICTIONS........................1
STANDARD PROCEDURE
STANDARD PROCEDURES - DRAINING
WATER FROM FUEL FILTER..............2STANDARD PROCEDURE - FUEL SYSTEM
AIR PURGE...........................2
STANDARD PROCEDURES - CLEANING
FUEL SYSTEM COMPONENTS............2
SPECIFICATIONS - TORQUE...............3
FUEL DELIVERY..........................4
FUEL INJECTION........................11
FUEL SYSTEM 2.5L TURBO
DIESEL
DESCRIPTION - DIESEL FUEL DELIVERY
SYSTEM
The fuel system on the 2.5L Common Rail Diesel
Engine uses a fuel injection pump and an Electronic
Control Module (ECM).
The fuel delivery system consists of the:
²Accelerator pedal
²Air cleaner housing/element
²Fuel filter/water separator
²Fuel heater
²Fuel heater relay
²Fuel transfer (lift) pump
²Fuel injection pump
²Fuel injectors
²Fuel tank
²Fuel tank filler/vent tube assembly
²Fuel tank filler tube cap
²Fuel tank module containing the rollover valve
and a fuel gauge sending unit (fuel level sensor).
²Fuel tubes/lines/hoses
²High-pressure fuel injector lines
²Low-pressure fuel supply lines
²Low-pressure fuel return line
²Overflow valve
²Quick-connect fittings
²Water draining
WARNING - HIGH FUEL SYSTEM PRESSURE
WARNING:: THE INJECTION PUMP SUPPLIES HIGH-
PRESSURE FUEL TO EACH INDIVIDUAL INJECTOR
THROUGH HIGH-PRESSURE LINES. FUEL UNDERTHIS AMOUNT OF PRESSURE CAN PENETRATE
SKIN AND CAUSE PERSONAL INJURY. WEAR
SAFETY GOGGLES AND ADEQUATE PROTECTIVE
CLOTHING. AVOID CONTACT WITH FUEL SPRAY
WHEN BLEEDING HIGH-PRESSURE FUEL LINES.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AIR IN FUEL
SYSTEM
Air will enter the fuel system whenever fuel supply
lines, separator filters, injection pump, high-pressure
lines or injectors are removed or disconnected. Air
trapped in the fuel system can result in hard start-
ing, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock. After service
is performed, air must be bled from the system
before starting the engine.
Inspect the fuel system from the fuel tank to the
injectors for loose connections. Leaking fuel is an
indicator of loose connections or defective seals. Air
can also enter the fuel system between the fuel tank
and the transfer pump. Inspect the fuel tank and fuel
lines for damage that might allow air into the sys-
tem.
DIAGNOSIS AND TESTING - FUEL SUPPLY
RESTRICTIONS
LOW-PRESSURE LINES
Fuel supply line restrictions or a defective fuel
transfer pump can cause starting problems and pre-
vent engine from accelerating. The starting problems
include; low power and/or white fog like exhaust.
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Test all fuel supply lines for restrictions or block-
age. Flush or replace as necessary. Bleed fuel system
of air once a fuel supply line has been replaced. Refer
to Air Bleed Procedure for procedures.
To test for fuel line restrictions, a vacuum restric-
tion test may be performed.
HIGH-PRESSURE LINES
Restricted (kinked or bent) high-pressure lines can
cause starting problems, poor engine performance,
engine mis-fire and white smoke from exhaust.
Examine all high-pressure lines for any damage.
Each radius on each high-pressure line must be
smooth and free of any bends or kinks.
Replace damaged, restricted or leaking high-pres-
sure fuel lines with correct replacement line.
CAUTION: High pressure lines cannot contact each
other or other components. Do not attempt to weld
high-pressure fuel lines or to repair lines that are
damaged. If line is kinked or bent, it must be
replaced. Use only recommended lines when
replacement of high-pressure fuel line is necessary.
STANDARD PROCEDURE
STANDARD PROCEDURES - DRAINING WATER
FROM FUEL FILTER
Refer to Fuel Filter/Water Separator removal/in-
stallation for procedures.
STANDARD PROCEDURE - FUEL SYSTEM AIR
PURGE
(1) Remove engine cover (Refer to 9 - ENGINE
COVER - REMOVAL).
(2) Remove cap from air purge fitting on the fuel
supply line. This fitting is located just behind the
alternator (Fig. 1).
(3) Attach a hose of about 1 or 2 meters to this fit-
ting using an appropriate connector.
(4) Direct the end of the hose into an appropriate
fuel container.
(5) Turn the ignition to the ªONº position,Do not
crank the engine.Keep key on until about 1 liter of
fuel has been pumped into the container.
(6) While keeping end of hose below fuel level in
conatiner, turn the ignition ªOFFº.
(7) Remove hose from air purge fitting on the fuel
supply line and replace cap.
(8) Install engine cover (Refer to 9 - ENGINE
COVER - INSTALLATION).
STANDARD PROCEDURES - CLEANING FUEL
SYSTEM COMPONENTS
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines, fuel rail, and fuel injection
pump. Very tight tolerances are used with these
parts. Dirt contamination could cause rapid part
wear and possible plugging of fuel injector nozzle
tip holes. This in turn could lead to possible engine
misfire. Always wash/clean any fuel system compo-
nent thoroughly before disassembly and then air
dry. Cap or cover any open part after disassembly.
Before assembly, examine each part for dirt, grease
or other contaminants and clean if necessary. When
installing new parts, lubricate them with clean
engine oil or clean diesel fuel only.
Fig. 1 AIR PURGE VALVE
1 - AIR PURGE VALVE CAP
2 - AIR PURGE VALVE
3 - ALTERNATOR
4 - ENGINE FRONT COVER
14a - 2 FUEL SYSTEMRG
FUEL SYSTEM 2.5L TURBO DIESEL (Continued)
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SPECIFICATIONS - TORQUE
2.5L DIESEL - TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Crankshaft Position Sensor Bolt 10.8 8 96
Boost Pressure / Intake Air Temperature
Sensor Bolts5.4 Ð 48
Fuel Pump Nuts 27.5 21 Ð
Fuel Line Fittings at Pump 27.5 21 Ð
Fuel Pump Sprocket Nut 88.3 65 Ð
Fuel Injector Retaining Bolts 32.4 24 Ð
High Pressure Fuel Lines 22 17 194
Fuel Rail Bolts 27.5 21 Ð
RGFUEL SYSTEM14a-3
FUEL SYSTEM 2.5L TURBO DIESEL (Continued)
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FUEL DELIVERY
TABLE OF CONTENTS
page page
FUEL RAIL
DESCRIPTION..........................4
OPERATION............................4
REMOVAL - FUEL RAIL...................4
INSTALLATION - FUEL RAIL................5
FUEL FILTER / WATER SEPARATOR
DESCRIPTION..........................5
OPERATION............................5
FUEL LINES
DESCRIPTION
DESCRIPTION........................6
DESCRIPTION - HIGH PRESSURE FUEL
LINES...............................6OPERATION - HIGH PRESSURE FUEL LINES . . 6
DIAGNOSIS AND TESTING - HIGH
PRESSURE FUEL LINES.................6
FUEL TRANSFER PUMP
DESCRIPTION..........................7
OPERATION............................7
FUEL INJECTION PUMP
DESCRIPTION..........................7
REMOVAL.............................7
INSTALLATION..........................9
WATER IN FUEL SENSOR
DESCRIPTION.........................10
OPERATION...........................10
FUEL RAIL
DESCRIPTION
The fuel rail is mounted to the cylinder head cover/
intake manifold (Fig. 1).
OPERATION
The fuel rail stores the fuel for the injectors at
high pressure. At the same time, the pressure oscil-
lations which are generated due to the high-pressure
pump delivery and the injection of fuel are dampened
by the rail volume.
The fuel rail is common to all cylinders, hence it's
name ªcommon railº. Even when large quantities of
fuel are extracted, the fuel rail maintains a constant
inner pressure. This ensures that the injection pres-
sure remains constant from the moment the injector
opens.
REMOVAL - FUEL RAIL
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(3) Disconnect fuel injector high pressure lines.
(4) Disconnect fuel rail supply line. (Fig. 2)
(5) Disconnect fuel rail return line. (Fig. 2)
(6) Disconnect fuel rail high pressure sensor con-
nector. (Fig. 2)
(7) Remove engine electrical harness retainers
from the fuel rail retaining bolts/studs. (Fig. 2)
(8) Remove fuel rail retaining bolts and remove
fuel rail (Fig. 2).Fig. 1 ENGINE COMPONENT LOCATIONS
1 - FUEL INJECTOR RETURN LINE
2 - FUEL INJECTOR HIGH PRESSURE LINE
3 - OIL SEPARATOR
4 - FUEL INJECTOR
5 - CAMSHAFT POSITION SENSOR
6 - BOOST PRESSURE/INTAKE AIR TEMPERATURE SENSOR
7 - EGR SOLENOID
8 - FUEL PRESSURE SENSOR
9 - CYLINDER HEAD COVER/INTAKE MANIFOLD
10 - FUEL RAIL
14a - 4 FUEL DELIVERYRG
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INSTALLATION - FUEL RAIL
(1) Install fuel rail to intake manifold/cylinder
head cover (Fig. 2). Torque retaining bolts to
27.5N´m.
(2) Install engine electrical harness retainers from
the fuel rail retaining bolts/studs. (Fig. 2)
(3) Connect fuel rail high pressure sensor electri-
cal connector. (Fig. 2)
(4) Connect fuel rail return line. (Fig. 2)
(5) Connect fuel rail supply line. (Fig. 2)
(6) Connect fuel injector high pressure lines. (Fig.
2)
(7) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
(8) Connect negative battery cable.
FUEL FILTER / WATER
SEPARATOR
DESCRIPTION
The fuel filter/water separator assembly is located
under the vehicle in front of the rear axle assembly
(Fig. 3). The assembly also includes the fuel heater
and Water-In-Fuel (WIF) sensor.
OPERATION
The fuel filter/water separator protects the fuel
injection pump by removing water and contaminants
from the fuel. 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 canister.
Fig. 2 FUEL RAIL COMPONENTS
1 - FUEL INJECTOR RETURN LINE
2 - FUEL INJECTOR HIGH PRESSURE LINE
3 - OIL SEPARATOR
4 - FUEL INJECTOR
5 - CAMSHAFT POSITION SENSOR
6 - BOOST PRESSURE/INTAKE AIR TEMPERATURE SENSOR
7 - EGR SOLENOID
8 - FUEL PRESSURE SENSOR
9 - CYLINDER HEAD COVER/INTAKE MANIFOLD
10 - FUEL RAIL
Fig. 3 FUEL FILTER/WATER SEPARATOR
1 - LIFT PUMP RETAINING BOLTS
2 - LIFT PUMP
3 - FUEL FILTER/WATER SEPARATOR HOUSING
4 - FUEL HEATER
5 - CHECK BALL
6 - O-RING
7 - FLOW DIVERTER
8 - FUEL FILTER
9 - O-RING
10 - FUEL FILTER BOWL ASSEMBLY
RGFUEL DELIVERY14a-5
FUEL RAIL (Continued)
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