fuel filter DODGE RAM 2002 Service Manual PDF

SPECIFICATIONS
TORQUE - DIESEL ENGINE
DESCRIPTION N m Ft. Lbs. In. Lbs.
Accelerator Pedal Position Sensor Bracket Bolts 12 9 105
Air Intake Housing Bolts 24 18 212
Banjo Fittings at top of Filter/Separator 24 18 212
Banjo Fittings at Fuel Return Lines 24 18 212
Banjo Fitting At Fuel Supply Line (Injector Pump) 24 18 212
Camshaft Position Sensor (CMP) Bolt 20 15 177
ECM Mounting Bolts 24 18 212
Engine Coolant Temperature (ECT) Sensor 14 10 124
Engine Lifting Bracket Bolts 77 57 681
Fuel Drain Manifold ªTº Fitting 12 9 106
Fuel Filter Canister Bracket Bolts 24 18 212
Fuel Filter Canister Mounting Nut 14 10 124
Fuel Filter Drain Valve Mounting Screws 3-5 2-4 30-40
Fuel Heater Screws 2-3 1-2 15-20
Fuel Injector Clamp Bolts 10 7 89
Fuel Pump Module Locknut 24-44 18-32 212-389
Fuel Tank Mounting Nuts 41 30 363
Fuel Transfer Pump Mounting Nuts 12 9 106
High-Pressure Fuel Line Fittings (at Injectors) 38 28 336
High-Pressure Fuel Line Fittings (at Pump) 24 18 212
High-Pressure Fuel Line Clamps-to-Intake Manifold 24 18 212
Hose Clamps at Intercooler Tube 8 6 72
Injection Pump-to-Injection Pump Gear Nut 170 125
Injection Pump Mounting Nuts 43 32 380
Intake Manifold Air Temperature (IAT) Sensor 14 10
Intake Manifold Air Heater Relay Bolts 4.5 40
Manifold Air Pressure (MAP) Sensor 14 10
PCM Mounting Bolts 4 35
Overflow Valve-to-Fuel Injection Pump 24 18
Water-In-Fuel (WIF) Sensor 2-3 15-20
14 - 94 FUEL INJECTION - DIESELBR/BE
FUEL INJECTION - DIESEL (Continued)

OPERATION
High-pressure fuel is supplied from the injection
pump, through a high-pressure fuel line, through a
steel connector and into the fuel injector. When fuel
pressure rises to approximately 31,026 kPa (4,500
psi), the needle valve spring tension is overcome. The
needle valve rises and fuel flows through the spray
holes in the nozzle tip into the combustion chamber.
The pressure required to lift the needle valve is the
nozzle opening pressure. This is sometimes referred
to as the ªpopº pressure setting.
Each fuel injector is connected to each high-pres-
sure fuel line with a steel connector (Fig. 11). This
steel connector is positioned into the cylinder head
and sealed with an o-ring. The connectors are sealed
to the high-pressure fuel lines with fittings (Fig. 11).
The ferrule (Fig. 11) on the end of the high-pressure
fuel line pushes against the steel connector when the
fuel line fitting is torqued into the cylinder head.
This torquing force provides a sealing pressure
between both the fuel line-to-connector and the fuel
connector-to-fuel injector.The fitting torque is
very critical.If the fitting is under torqued, the
mating surfaces will not seal and a high-pressure
fuel leak will result. If the fitting is over torqued, the
connector and injector will deform and also cause a
high-pressure fuel leak. This leak will be inside the
cylinder head and will not be visible. The result will
be a possible fuel injector miss-fire and low power.
The fuel injectors use hole type nozzles (Fig. 12).
High-pressure flows into the side of the injector and
causes the injector needle to lift and fuel to be
injected. The clearances in the nozzle bore (Fig. 12)
are extremely small and any sort of dirt or contami-
nants will cause the injector to stick. Because of this,
it is very important to do a thorough cleaning of any
Fig. 11 Fuel Injector Connections
1 - CONNECTOR
2 - O-RING
3 - FERRULE
4 - FITTING
5 - FUEL LINE
6 - INJECTOR
Fig. 12 Fuel Injector Spray Pattern
1 - INJECTOR
2 - CLEARANCE
3 - SHIM
4 - NOZZLE
Fig. 13 Fuel Injector Edge Filter
1 - EDGE FILTER
2 - FITTING
3 - FUEL INJECTOR
14 - 98 FUEL INJECTION - DIESELBR/BE
FUEL INJECTOR (Continued)

lines before opening up any fuel system component.
Always cover or cap any open fuel connections before
a fuel system repair is performed.
Each fuel injector connector tube contains an edge
filter (Fig. 13) that breaks up small contaminants
that enter the injector. The edge filter uses the injec-
tors pulsating high-pressure to break up most parti-
cles so they are small enough to pass through the
injector.The edge filters are not a substitute for
proper cleaning and covering of all fuel system
components during repair.
The bottom of each fuel injector is sealed to the
cylinder head with a1.5mmthick copper shim (gas-
ket) (Fig. 12). The correct thickness shim must
always be re-installed after removing an injector.
Fuel pressure in the injector circuit decreases after
injection. The injector needle valve is immediately
closed by the needle valve spring and fuel flow into
the combustion chamber is stopped. Exhaust gases
are prevented from entering the injector nozzle by
the needle valve.
DIAGNOSIS AND TESTINGÐFUEL INJECTOR
TEST
The fuel injectors are located in the top of the cyl-
inder head between the intake/exhaust valves (Fig.
14).A leaking fuel injector can cause fuel knock, poor
performance, black smoke, poor fuel economy and
rough engine idle. If fuel injector needle valve does
not operate properly, engine may misfire and produce
low power.
A leak in injection pump-to-injector high-pressure
fuel line can cause many of same symptoms as mal-
functioning injector. Inspect for leaks in high-pres-
sure lines before checking for malfunctioning fuel
injector.
WARNING: THE INJECTION PUMP SUPPLIES HIGH-
PRESSURE FUEL OF UP TO APPROXIMATELY
120,000 kPa (17,400 psi) TO EACH INDIVIDUAL
INJECTOR THROUGH HIGH-PRESSURE LINES.
FUEL UNDER THIS AMOUNT OF PRESSURE CAN
PENETRATE SKIN AND CAUSE PERSONAL INJURY.
WEAR SAFETY GOGGLES AND ADEQUATE PRO-
TECTIVE CLOTHING. AVOID CONTACT WITH FUEL
SPRAY WHEN BLEEDING HIGH-PRESSURE FUEL
LINES.
WARNING: DO NOT BLEED AIR FROM FUEL SYS-
TEM OF A HOT ENGINE. DO NOT ALLOW FUEL TO
SPRAY ONTO EXHAUST MANIFOLD WHEN BLEED-
ING AIR FROM FUEL SYSTEM.
(1) To determine which fuel injector is malfunc-
tioning, run engine and isolate each cylinder using
DRB scan tool.The DRB scan tool lists the injec-
tor firing order in both cylinder numerical
order (1±2±3±4±5±6), and actual firing order
(1±5±3±6±2±4).
Fig. 14 Fuel Injector Connections
1 - CONNECTOR
2 - O-RING
3 - FERRULE
4 - FITTING
5 - FUEL LINE
6 - INJECTOR
Fig. 15 Inspecting Injector Operation
1 - HIGH-PRESSURE FUEL LINE
BR/BEFUEL INJECTION - DIESEL 14 - 99
FUEL INJECTOR (Continued)

FUEL TEMPERATURE SENSOR
DESCRIPTION
Two different fuel temperature sensors are used.
One of the sensors is located inside of the Bosch
VP44 fuel injection pump and is a non-serviceable
part. The other fuel temperature sensor is located in
the top of the fuel filter housing and is serviceable
(serviceable if replacing the fuel heater).
OPERATION
The sensor located in the Bosch VP44 fuel injection
pump is used to check fuel temperature within the
injection pump and to set a Diagnostic Trouble Code
(DTC) if a specific high fuel temperature has been
reached. If high temperature has been reached,
engine power will be de-rated by the Engine Control
Module (ECM).
The sensor located in the top of the fuel filter hous-
ing is used to control the fuel heater element. Refer
to Fuel Heater Description and Operation for addi-
tional information.
INTAKE AIR HEATER
DESCRIPTION
The intake manifold air heater element assembly
is located in the top of the intake manifold (Fig. 25).
OPERATION
The air heater elements are used to heat incoming
air to the intake manifold. This is done to help
engine starting and improve driveability with cool or
cold outside temperatures.
Electrical supply for the 2 air heater elements is
controlled by the Engine Control Module (ECM)
through the 2 air heater relays. Refer to Intake Man-
ifold Air Heater Relays for more information.
Two heavy-duty cables connect the 2 air heater ele-
ments to the 2 air heater relays. Each of these cables
will supply approximately 95 amps at 12 volts to an
individual heating element within the heater block
assembly.
Refer to the Powertrain Diagnostic Procedures
manual for an electrical operation and complete
description of the intake heaters, including pre-heat
and post-heat cycles.
REMOVAL
The 2 intake manifold air heater elements are
attached to a metal block located at the top of the
intake manifold (Fig. 26). If servicing either of the
heater elements, the entire block/element assembly
must be replaced.
(1) Disconnect both negative battery cables at both
batteries.
(2) Disconnect clamp from rubber hose at air
intake housing.
(3) Disconnect rubber hose at air intake housing.
Fig. 25 Air Heater Elements Location
1 - AIR HEATER ELEMENTS
2 - LOWER GASKET
3 - BLOCK
4 - UPPER GASKET
Fig. 26 Intake Manifold Air Heater Element Location
1 - AIR HEATER ELEMENTS
2 - LOWER GASKET
3 - BLOCK
4 - UPPER GASKET
14 - 104 FUEL INJECTION - DIESELBR/BE

IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan gas-
ket surface (Fig. 2). Refer to this information when
ordering replacement parts.
GEAR RATIOS
The 46RE gear ratios are:
1st.................................2.45:1
2nd................................1.45:1
3rd.................................1.00:1
4th.................................0.69:1
Rev..................................2.21
OPERATION
The application of each driving or holding compo-
nent is controlled by the valve body based upon the
manual lever position, throttle pressure, and gover-
nor pressure. The governor pressure is a variable
pressure input to the valve body and is one of the
signals that a shift is necessary. First through fourth
gear are obtained by selectively applying and releas-
ing the different clutches and bands. Engine power is
thereby routed to the various planetary gear assem-
blies which combine with the overrunning clutch
assemblies to generate the different gear ratios. The
torque converter clutch is hydraulically applied and
is released when fluid is vented from the hydraulic
circuit by the torque converter control (TCC) solenoid
on the valve body. The torque converter clutch is con-
trolled by the Powertrain Control Module (PCM). The
torque converter clutch engages in fourth gear, and
in third gear under various conditions, such as when
the O/D switch is OFF, when the vehicle is cruising
on a level surface after the vehicle has warmed up.
The torque converter clutch will disengage momen-
tarily when an increase in engine load is sensed by
the PCM, such as when the vehicle begins to go
uphill or the throttle pressure is increased. The
torque converter clutch feature increases fuel econ-
omy and reduces the transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear
only and the direct clutch is applied in all ranges
except fourth gear, the transmission operation for
park, neutral, and first through third gear will be
described first. Once these powerflows are described,
the third to fourth shift sequence will be described.
1 - TORQUE CONVERTER 11 - DIRECT CLUTCH
2 - INPUT SHAFT 12 - PLANETARY GEAR
3 - OIL PUMP 13 - OUTPUT SHAFT
4 - FRONT BAND 14 - SEAL
5 - FRONT CLUTCH 15 - INTERMEDIATE SHAFT
6 - REAR CLUTCH 16 - OVERDRIVE OVERRUNNING CLUTCH
7 - PLANETARIES 17 - DIRECT CLUTCH SPRING
8 - REAR BAND 18 - OVERDRIVE PISTON RETAINER
9 - OVERRUNNING CLUTCH 19 - FILTER
10 - OVERDRIVE CLUTCH 20 - VALVE BODY
Fig. 2 Transmission Part And Serial Number
Location
1 - PART NUMBER
2 - BUILD DATE
3 - SERIAL NUMBER
BR/BEAUTOMATIC TRANSMISSION - 46RE 21 - 91
AUTOMATIC TRANSMISSION - 46RE (Continued)

IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan gas-
ket surface (Fig. 2). Refer to this information when
ordering replacement parts.
GEAR RATIOS
The 47RE gear ratios are:
1st.................................2.45:1
2nd................................1.45:1
3rd.................................1.00:1
4th.................................0.69:1
Rev..................................2.21
OPERATION
The application of each driving or holding compo-
nent is controlled by the valve body based upon the
manual lever position, throttle pressure, and gover-
nor pressure. The governor pressure is a variable
pressure input to the valve body and is one of the
signals that a shift is necessary. First through fourth
gear are obtained by selectively applying and releas-
ing the different clutches and bands. Engine power is
thereby routed to the various planetary gear assem-
blies which combine with the overrunning clutch
assemblies to generate the different gear ratios. The
torque converter clutch is hydraulically applied and
is released when fluid is vented from the hydraulic
circuit by the torque converter control (TCC) solenoid
on the valve body. The torque converter clutch is con-
trolled by the Powertrain Control Module (PCM). The
torque converter clutch engages in fourth gear, and
in third gear under various conditions, such as when
the O/D switch is OFF, when the vehicle is cruising
on a level surface after the vehicle has warmed up.
The torque converter clutch will disengage momen-
tarily when an increase in engine load is sensed by
the PCM, such as when the vehicle begins to go
uphill or the throttle pressure is increased. The
torque converter clutch feature increases fuel econ-
omy and reduces the transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear
only and the direct clutch is applied in all ranges
except fourth gear, the transmission operation for
park, neutral, and first through third gear will be
described first. Once these powerflows are described,
the third to fourth shift sequence will be described.
1 - TORQUE CONVERTER 11 - DIRECT CLUTCH
2 - INPUT SHAFT 12 - PLANETARY GEAR
3 - OIL PUMP 13 - OUTPUT SHAFT
4 - FRONT BAND 14 - SEAL
5 - FRONT CLUTCH 15 - INTERMEDIATE SHAFT
6 - REAR CLUTCH 16 - OVERDRIVE OVERRUNNING CLUTCH
7 - PLANETARIES 17 - DIRECT CLUTCH SPRING
8 - REAR BAND 18 - OVERDRIVE PISTON RETAINER
9 - OVERRUNNING CLUTCH 19 - FILTER
10 - OVERDRIVE CLUTCH 20 - VALVE BODY
Fig. 2 Transmission Part and Serial Number
Location
1 - PART NUMBER
2 - BUILD DATE
3 - SERIAL NUMBER
BR/BEAUTOMATIC TRANSMISSION - 47RE 21 - 263
AUTOMATIC TRANSMISSION - 47RE (Continued)

²Absolute MAP When Misfire OccurredÐ
The stored MAP reading at the time of failure.
Informs the user at what engine load the failure
occurred.
²Absolute MAPÐ A live reading of engine load
to aid the user in accessing the Similar Conditions
Window.
²RPM When Misfire OccurredÐ The stored
RPM reading at the time of failure. Informs the user
at what engine RPM the failure occurred.
²Engine RPMÐ A live reading of engine RPM
to aid the user in accessing the Similar Conditions
Window.
²Adaptive Memory FactorÐ The PCM utilizes
both Short Term Compensation and Long Term Adap-
tive to calculate the Adaptive Memory Factor for
total fuel correction.
²200 Rev CounterÐ Counts 0±100 720 degree
cycles.
²SCW Cat 200 Rev CounterÐ Counts when in
similar conditions.
²SCW FTP 1000 Rev CounterÐ Counts 0±4
when in similar conditions.
²Misfire Good Trip CounterÐ Counts up to
three to turn OFF the MIL.
²Misfire DataÐ Data collected during test.
²Test Done This TripÐ Indicates YES when the
test is done.
OPERATION - NON-MONITORED CIRCUITS -
GAS ENGINES
The PCM does not monitor the following circuits,
systems and conditions that could have malfunctions
causing driveability problems. The PCM might not
store diagnostic trouble codes for these conditions.
However, problems with these systems may cause the
PCM to store diagnostic trouble codes for other sys-
tems or components.EXAMPLE:a fuel pressure
problem will not register a fault directly, but could
cause a rich/lean condition or misfire. This could
cause the PCM to store an oxygen sensor or misfire
diagnostic trouble code
FUEL PRESSURE
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor or fuel system diag-
nostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables.CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine
cylinder compression.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or
leaking exhaust system, although it may set a fuel
system fault.
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The PCM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injector
is installed. However, these could result in a rich or
lean condition causing the PCM to store a diagnostic
trouble code for either misfire, an oxygen sensor, or
the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen
content when the system is in closed loop, it cannot
determine excessive oil consumption.
THROTTLE BODY AIR FLOW
The PCM cannot detect a clogged or restricted air
cleaner inlet or filter element.
VACUUM ASSIST
The PCM cannot detect leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices. However, these could cause the PCM
to store a MAP sensor diagnostic trouble code and
cause a high idle condition.
PCM SYSTEM GROUND
The PCM cannot determine a poor system ground.
However, one or more diagnostic trouble codes may
be generated as a result of this condition. The mod-
ule should be mounted to the body at all times, also
during diagnostic.
PCM CONNECTOR ENGAGEMENT
The PCM may not be able to determine spread or
damaged connector pins. However, it might store
diagnostic trouble codes as a result of spread connec-
tor pins.
OPERATION - NON-MONITORED CIRCUITS -
DIESEL
The PCM and/or the ECM will not monitor certain
malfunctioning circuits or components that could
cause driveability problems. Also, a Diagnostic Trou-
ble Code (DTC) might not be stored for these mal-
functions. However, problems with these circuits or
components may cause the PCM/ECM to store DTC's
for other circuits or components.EXAMPLES:A cyl-
inder with low compression will not set a DTC
25 - 24 EMISSIONS CONTROLBR/BE
EMISSIONS CONTROL (Continued)

directly, but may cause an engine misfire. This in
turn may cause the ECM to set a DTC for an engine
misfire. Or, a dirty or plugged air filter will not set a
DTC directly, but may cause lack of turbocharger
boost. This in turn may cause the ECM to set a DTC
for a boost pressure malfunction.
FUEL PRESSURE
Primary fuel pressure from the fuel tank to the
fuel injection pump is supplied by the low-pressure
fuel transfer pump. High-pressure to the fuel injec-
tors is supplied by the fuel injection pump. The ECM
cannot detect actual fuel pressure, a clogged fuel fil-
ter, clogged fuel screen, or a pinched fuel supply or
return line. However, a DTC may be set due to an
engine misfire.
CYLINDER COMPRESSION
The ECM cannot detect uneven, low, or high
engine cylinder compression. However, these could
result in a possible misfire which may set a DTC.
EXHAUST SYSTEM
The ECM cannot detect a plugged, restricted or
leaking exhaust system. However, DTC's may be set
for engine misfire, high intake manifold temperature,
high engine coolant temperature, turbocharger over-
boost or turbocharger underboost.
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The ECM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injectoris installed. However, these could result in a possible
misfire which may set a DTC.
EXCESSIVE OIL CONSUMPTION
The ECM cannot determine excessive oil consump-
tion. However, if excess oil consumption is high
enough, it could result in a possible engine misfire
which may set a DTC.
AIR FLOW
The ECM cannot detect a clogged, restricted or
dirty air filter element, or a restriction in the air
inlet system. However, these could result in a possi-
ble misfire which may set a DTC.
AIR PRESSURE LEAKS
The ECM cannot detect leaks or restrictions in the
air intake system. However, these could cause the
ECM to store a Manifold Air Pressure (MAP) sensor
DTC (boost pressure problem detected).
PCM/ECM SYSTEM GROUNDS
The PCM/ECM cannot directly determine poor sys-
tem grounds. However, one or more DTC's may be
generated as a result of poor grounds.
PCM/ECM CONNECTOR ENGAGEMENT
The PCM/ECM may not be able to determine
spread, damaged or corroded connector pins. How-
ever, it might store DTC's as a result of spread con-
nector pins (circuits that are open).
BR/BEEMISSIONS CONTROL 25 - 25
EMISSIONS CONTROL (Continued)

EVAPORATIVE EMISSIONS
TABLE OF CONTENTS
page page
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAP SYSTEM............32
SPECIFICATIONS
TORQUE - EVAP SYSTEM..............32
CCV HOSE
DESCRIPTION - 8.0L....................33
OPERATION - 8.0L......................33
EVAP/PURGE SOLENOID
DESCRIPTION.........................33
OPERATION...........................33
REMOVAL.............................33
INSTALLATION.........................34
FUEL FILLER CAP
DESCRIPTION.........................34
OPERATION...........................34
REMOVAL/INSTALLATION................34
LEAK DETECTION PUMP
DESCRIPTION.........................34OPERATION...........................34
REMOVAL.............................34
INSTALLATION.........................34
P C V VA LV E
DESCRIPTION - V-8 ENGINES.............35
OPERATION - V-8 ENGINES...............35
DIAGNOSIS AND TESTING - PCV VALVE -
5.9L................................36
VACUUM LINES
DESCRIPTION.........................37
VAPOR CANISTER
DESCRIPTION.........................37
OPERATION...........................37
REMOVAL.............................38
INSTALLATION.........................38
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAP SYSTEM
The evaporation control system prevents the emis-
sion of fuel tank vapors into the atmosphere. When
fuel evaporates in the fuel tank, the vapors pass
through vent hoses or tubes into the two charcoal
filled evaporative canisters. The canisters tempo-
rarily hold the vapors. The Powertrain Control Mod-
ule (PCM) allows intake manifold vacuum to draw
vapors into the combustion chambers during certain
operating conditions.
All 5.9L/8.0L gasoline powered engines use a duty
cycle purge system. The PCM controls vapor flow byoperating the duty cycle EVAP purge solenoid. Refer
to Duty Cycle EVAP Canister Purge Solenoid for
additional information.
When equipped with certain emissions packages, a
Leak Detection Pump (LDP) will be used as part of
the evaporative system. This pump is used as part of
OBD II requirements. Refer to Leak Detection Pump
in this group for additional information.
NOTE: The hoses used in this system are specially
manufactured. If replacement becomes necessary, it
is important to use only fuel resistant hose.
SPECIFICATIONS
TORQUE - EVAP SYSTEM
DESCRIPTION N´m Ft. Lbs. In. Lbs.
EVAP Canister Mounting Nuts 9 80
Leak Detection Pump Mounting Screws 1 11
Leak Detection Pump Filter Mounting Bolt 7 65
25 - 32 EVAPORATIVE EMISSIONSBR/BE

INSTALLATION
(1) Install solenoid assembly to support bracket.
(2) Connect vacuum harness.
(3) Connect wiring connector.
FUEL FILLER CAP
DESCRIPTION
The plastic fuel tank filler tube cap is threaded
onto the end of the fuel fill tube. Certain models are
equipped with a 1/4 turn cap.
OPERATION
The loss of any fuel or vapor out of fuel filler tube
is prevented by the use of a pressure-vacuum fuel fill
cap. Relief valves inside the cap will release fuel tank
pressure at predetermined pressures. Fuel tank vac-
uum will also be released at predetermined values.
This cap must be replaced by a similar unit if
replacement is necessary. This is in order for the sys-
tem to remain effective.
CAUTION: Remove fill cap before servicing any fuel
system component to relieve tank pressure. If
equipped with a Leak Detection Pump (LDP), the
cap must be tightened securely. If cap is left loose,
a Diagnostic Trouble Code (DTC) may be set.
REMOVAL/INSTALLATION
If replacement of the 1/4 turn fuel tank filler tube
cap is necessary, it must be replaced with an identi-
cal cap to be sure of correct system operation.
CAUTION: Remove the fuel tank filler tube cap to
relieve fuel tank pressure. The cap must be
removed prior to disconnecting any fuel system
component or before draining the fuel tank.
LEAK DETECTION PUMP
DESCRIPTION
The Leak Detection Pump (LDP) is used only with
certain emission packages.
The LDP is a device used to detect a leak in the
evaporative system.
The pump contains a 3 port solenoid, a pump that
contains a switch, a spring loaded canister vent valve
seal, 2 check valves and a spring/diaphragm.
OPERATION
Immediately after a cold start, engine temperature
between 40ÉF and 86ÉF, the 3 port solenoid is briefly
energized. This initializes the pump by drawing airinto the pump cavity and also closes the vent seal.
During non-test test conditions, the vent seal is held
open by the pump diaphragm assembly which pushes
it open at the full travel position. The vent seal will
remain closed while the pump is cycling. This is due
to the operation of the 3 port solenoid which prevents
the diaphragm assembly from reaching full travel.
After the brief initialization period, the solenoid is
de-energized, allowing atmospheric pressure to enter
the pump cavity. This permits the spring to drive the
diaphragm which forces air out of the pump cavity
and into the vent system. When the solenoid is ener-
gized and de-energized, the cycle is repeated creating
flow in typical diaphragm pump fashion. The pump
is controlled in 2 modes:
PUMP MODE:The pump is cycled at a fixed rate
to achieve a rapid pressure build in order to shorten
the overall test time.
TEST MODE:The solenoid is energized with a
fixed duration pulse. Subsequent fixed pulses occur
when the diaphragm reaches the switch closure
point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5 inches
of water.
When the pump starts, the cycle rate is quite high.
As the system becomes pressurized pump rate drops.
If there is no leak the pump will quit. If there is a
leak, the test is terminated at the end of the test
mode.
If there is no leak, the purge monitor is run. If the
cycle rate increases due to the flow through the
purge system, the test is passed and the diagnostic is
complete.
The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.
REMOVAL
The LDP and LDP filter are attached to a bracket
mounted to the right-inner fender (Fig. 2). The LDP
and LDP filter are replaced (serviced) as one unit.
(1) Carefully remove hose at LDP filter.
(2) Remove LDP filter mounting bolt and remove
from vehicle.
(3) Carefully remove vapor/vacuum lines at LDP.
(4) Disconnect electrical connector at LDP (Fig. 2).
(5) Remove LDP mounting screws and remove
LDP from vehicle.
INSTALLATION
The LDP and LDP filter are attached to a bracket
mounted to the right-inner fender (Fig. 2) . The LDP
and LDP filter are replaced (serviced) as one unit.
(1) Install LDP to mounting bracket. Tighten
screws to 1 N´m (11 in. lbs.) torque.
25 - 34 EVAPORATIVE EMISSIONSBR/BE
EVAP/PURGE SOLENOID (Continued)