Dodge Dakota (R1). Manual — part 810
SPECIFICATIONS
SPECIFICATIONS - TORQUE - EVAP SYSTEM
DESCRIPTION
N·m
Ft. Lbs.
In. Lbs.
EVAP Canister Mounting Nut
17-24
150-210
EVAP Canister Purge Solenoid Mounting Bolt – Except 2.5L
Engine
11
95
EVAP Canister Purge Solenoid Mounting Nuts – 2.5L Engine
8
75
Leak Detection Pump (LDP) Mounting Screws
1
11
CCV HOSE
DESCRIPTION - 2.5L
2.5L 4–cylinder engines are equipped with a
Crankcase Ventilation (CCV) system. The CCV sys-
tem performs the same function as a conventional
PCV system, but does not use a vacuum controlled
valve.
A molded vacuum tube connects a fitting on the
intake manifold to a fixed orifice fitting of a cali-
brated size. This fitting meters the amount of crank-
case vapors drawn out of the engine. The fixed orifice
fitting is located on the side of cylinder head (valve)
cover (Fig. 1).
A fresh air supply hose from the air cleaner hous-
ing is connected to a fitting at the top/rear of cylinder
head cover (Fig. 1).
When the engine is operating, fresh air enters the
engine and mixes with crankcase vapors. Engine vac-
uum draws the vapor/air mixture through the fixed
orifice and into the intake manifold. The vapors are
then consumed during engine combustion.
EVAP/PURGE SOLENOID
DESCRIPTION
The duty cycle EVAP canister purge solenoid (DCP)
regulates the rate of vapor flow from the EVAP can-
ister to the intake manifold. The Powertrain Control
Module (PCM) operates the solenoid.
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged. The
PCM de-energizes the solenoid during open loop oper-
ation.
The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM cycles
(energizes and de-energizes) the solenoid 5 or 10
times per second, depending upon operating condi-
tions. The PCM varies the vapor flow rate by chang-
ing solenoid pulse width. Pulse width is the amount
of time that the solenoid is energized. The PCM
adjusts solenoid pulse width based on engine operat-
ing condition.
REMOVAL
3.9/5.2/5.9L Engines: The duty cycle EVAP canister
purge solenoid is located at left-rear side of engine com-
partment near power brake vacuum unit (Fig. 2).
2.5L Engine: The solenoid is located at right-rear
side of engine compartment (Fig. 3).
(1) Disconnect electrical wiring connector at solenoid
(2) Disconnect vacuum harness at solenoid.
(3) Remove 2 support bracket mounting nuts.
(4) Remove solenoid and its support bracket from
vehicle.
Fig. 1 CCV System—2.5L Engine
1 - FIXED ORIFICE FITTING
2 - AIR INLET FITTING
3 - CCV TUBE
4 - CCV TUBE
25 - 24
EVAPORATIVE EMISSIONS
AN
EVAPORATIVE EMISSIONS (Continued)
INSTALLATION
3.9/5.2/5.9L Engines: The duty cycle EVAP canister
purge solenoid is located at left-rear side of engine com-
partment near power brake vacuum unit (Fig. 2).
2.5L Engine: The solenoid is located at right-rear
side of engine compartment (Fig. 3).
(1) Position EVAP canister purge solenoid and its
mounting bracket.
(2) Install mounting nuts and tighten to 8 N·m (75
in. lbs.) torque.
(3) Connect vacuum harness and 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 California emissions package and a
Leak Detection Pump (LDP), the cap must be tight-
ened 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.
Fig. 2 Duty Cycle EVAP Canister Purge Solenoid
1 - BRACKET NUTS (2)
2 - EVAP CANISTER PURGE SOLENOID
3 - EVAP SYSTEM TEST PORT (IF EQUIPPED)
4 - VACUUM LINES
5 - ELECTRICAL CONNECTOR
Fig. 3 Duty Cycle EVAP Canister Purge Solenoid—
2.5L Engine
1 - DUTY CYCLE SOLENOID
2 - CYLINDER HEAD COVER
3 - VACUUM HOSES
4 - BRACKET NUTS (2)
AN
EVAPORATIVE EMISSIONS
25 - 25
EVAP/PURGE SOLENOID (Continued)
Immediately after a cold start, engine temperature
between 40°F and 86°F, the 3 port solenoid is briefly
energized. This initializes the pump by drawing air into
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 ini-
tialization 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 energized 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.
A typical system schematic is shown in (Fig. 4).
Fig. 4 Evaporative System Monitor Schematic—Typical
1 - DUTY CYCLE PURGE SOLENOID (DCPS) DRIVER
2 - POWERTRAIN CONTROL MODULE (PCM)
3 - 3-PORT SOLENOID DRIVER
4 - REMOTE FILTER
5 - COMBINED CANISTER VENT VALVE & LEAK DETECTION
PUMP
6 - CANISTER
7 - TANK ROLLOVER VALVE & VAPOR FLOW CONTROL ORIFICE
8 - INTAKE MANIFOLD
9 - THROTTLE BODY
10 - DCPS
11 - SWITCH SIGNAL INPUT TO THE PCM
12 - ENGINE VACUUM LINE
25 - 26
EVAPORATIVE EMISSIONS
AN
LEAK DETECTION PUMP (Continued)
REMOVAL
The LDP is located in the engine compartment
under the battery tray and Power Distribution Cen-
ter (PDC) (Fig. 5). The LDP filter is attached to the
outside of battery tray (Fig. 6). The LDP and LDP fil-
ter are replaced (serviced) as one unit.
(1) Disconnect negative battery cable at battery.
(2) Remove battery. Refer to 8, Battery for proce-
dures.
(3) Carefully disconnect rubber hose from bottom
of LDP filter (Fig. 6).
(4) Remove clip retaining LDP filter to battery
tray (Fig. 6)and remove filter from tray.
(5) Disconnect battery temperature sensor pigtail
wiring harness at bottom of battery tray.
(6) To gain access to LDP, the PDC must be par-
tially removed. Remove PDC-to-fender mounting
screw at rear of PDC. Unsnap PDC from battery
tray. To prevent damage to PDC wiring, carefully
position PDC to gain access to LDP.
(7) Remove battery tray. Refer to 8, Battery for
procedures.
(8) Carefully remove vapor/vacuum lines at LDP.
(9) Disconnect electrical connector at LDP.
(10) Remove 3 LDP mounting screws (Fig. 7) and
remove LDP from vehicle.
INSTALLATION
The LDP is located in the engine compartment
under the battery tray and Power Distribution Cen-
ter (PDC) (Fig. 5). The LDP filter is attached to the
outside of battery tray (Fig. 6). The LDP and LDP fil-
ter are replaced (serviced) as one unit.
(1) Install LDP to bottom of battery tray. Tighten
screws to 1 N·m (11 in. lbs.) torque.
(2) Carefully install vapor/vacuum lines to LDP.
The vapor/vacuum lines and hoses must be
firmly
connected.
Check
the
vapor/vacuum
lines at the LDP, LDP filter and EVAP canister
Fig. 5 Leak Detection Pump (LDP) Location
1 - BATTERY
2 - LEAK DETECTION PUMP (LDP)
Fig. 6 LDP Filter Location
1 - LDP FILTER
2 - LDP FILTER-TO-LDP HOSE
3 - BATTERY TRAY
4 - LDP MOUNTING CLIP
Fig. 7 Leak Detection Pump (LDP) Mounting Screws
1 - BATTERY TRAY
2 - LDP
3 - LDP MOUNTING SCREWS (3)
AN
EVAPORATIVE EMISSIONS
25 - 27
LEAK DETECTION PUMP (Continued)
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