clock DODGE RAM 1500 1998 2.G Workshop Manual

Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three 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 conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that 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, thus permitting the spring to drive the dia-
phragm 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 con-
trolled 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 length.
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 7.5º H20.
The cycle rate of pump strokes is quite rapid as the
system begins to pump up to this pressure. As the
pressure increases, the cycle rate starts to drop off. If
there is no leak in the system, the pump would even-
tually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .040º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases due
to the flow through the purge system, the leak check
portion of 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.
Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicatedby a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the Air Fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S sensor output. The programmed
memory acts as a self calibration tool that the engine
controller uses to compensate for variations in engine
specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the
actual fuel-air ratio with the O2S sensor (short term)
and multiplying that with the program long-term
(adaptive) memory and comparing that to the limit,
it can be determined whether it will pass an emis-
sions test. If a malfunction occurs such that the PCM
cannot maintain the optimum A/F ratio, then the
MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. This can increase vehicle emissions
and deteriorate engine performance, driveability and
fuel economy.
The catalyst monitor uses dual oxygen sensors
(O2S's) to monitor the efficiency of the converter. The
dual O2S's sensor strategy is based on the fact that
as a catalyst deteriorates, its oxygen storage capacity
and its efficiency are both reduced. By monitoring
the oxygen storage capacity of a catalyst, its effi-
ciency can be indirectly calculated. The upstream
DREMISSIONS CONTROL 25 - 3
EMISSIONS CONTROL (Continued)

REMOVAL
3.7L V-6 / 4.7L V-8
The PCV valve is located on the oil filler tube (Fig.
22). Two locating tabs are located on the side of the
valve (Fig. 22). These 2 tabs fit into a cam lock in the
oil filler tube. An o-ring seals the valve to the filler
tube.
(1) Disconnect PCV line/hose (Fig. 22) by discon-
necting rubber hose at PCV valve fitting.
(2) Remove PCV valve at oil filler tube by rotating
PCV valve downward (counter-clockwise) until locat-
ing tabs have been freed at cam lock (Fig. 22). After
tabs have cleared, pull valve straight out from filler
tube.To prevent damage to PCV valve locating
tabs, valve must be pointed downward for
removal. Do not force valve from oil filler tube.
(3) After valve is removed, check condition of valve
o-ring (Fig. 22).
5.7L V-8
The PCV valve is mounted into the top of the
intake manifold, located to the right / rear of the
throttle body (Fig. 12). The PCV valve is sealed to
the intake manifold with 2 o-rings (Fig. 13).
(1) Remove PCV valve by rotating counter-clock-
wise 90 degrees until locating tabs have been freed.
After tabs have cleared, pull valve straight up from
intake manifold.(2) After valve is removed, check condition of 2
valve o-rings.
INSTALLATION
3.7L V6 / 4.7L V-8
The PCV valve is located on the oil filler tube. Two
locating tabs are located on the side of the valve.
These 2 tabs fit into a cam lock in the oil filler tube.
An o-ring seals the valve to the filler tube.
(1) Return PCV valve back to oil filler tube by
placing valve locating tabs into cam lock. Press PCV
valve in and rotate valve upward. A slight click will
be felt when tabs have engaged cam lock. Valve
should be pointed towards rear of vehicle.
(2) Connect PCV line/hose and rubber hose to PCV
valve.
Fig. 21 CHECK VALVES - PCV SYSTEM - 3.7L V-6 /
4.7L V-8
1 - CONNECTING HOSES
2 - CHECK VALVES
Fig. 22 PCV VALVE/OIL FILLER TUBE LOCATION -
3.7L V-6 / 4.7L V-8
1 - O-RING
2 - LOCATING TABS
3 - CAM LOCK
4 - OIL FILLER TUBE
5 - PCV LINE/HOSE
6 - P C V VA LV E
DREVAPORATIVE EMISSIONS 25 - 21
PCV VALVE (Continued)

5.7L V-8
(1) Clean out intake manifold opening.
(2) Check condition of 2 o-rings on PCV valve.
(3) Apply engine oil to 2 o-rings.
(4) Place PCV valve into intake manifold and
rotate 90 degrees clockwise for installation.
VACUUM LINES
DESCRIPTION
A vacuum schematic for emission related items can
be found on the vehicles VECI label. Refer to Vehicle
Emission Control Information (VECI) Label for label
location.
VAPOR CANISTER
DESCRIPTION
Two, maintenance free, EVAP canisters are used.
Both canisters are mounted into a two-piece support
bracket located near the front of the fuel tank (Fig.
23).
OPERATION
Two, maintenance free, EVAP canisters are
used.The EVAP canisters are filled with granules of
an activated carbon mixture. Fuel vapors entering
the EVAP canisters are absorbed by the charcoal
granules.
Fuel tank pressure vents into the EVAP canisters.
Fuel vapors are temporarily held in the canisters
until they can be drawn into the intake manifold.
The duty cycle EVAP canister purge solenoid allows
the EVAP canisters to be purged at predetermined
times and at certain engine operating conditions.
REMOVAL
Two, maintenance free, EVAP canisters are used.
Both canisters are mounted into a two-piece support
bracket located near the front of the fuel tank (Fig.
23).
(1) Raise and support vehicle.
(2) Remove fuel tubes/lines at each EVAP canister.
Note location of tubes/lines before removal for easier
installation.
(3) Remove lower support bracket (Fig. 24).
(4) Remove mounting nuts at top of each canister
(Fig. 24).
(5) Remove each canister from upper support
bracket.
INSTALLATION
(1) Place each canister into upper support bracket
and install nuts. Refer to Torque Specifications.
(2) Install lower support bracket. Refer to Torque
Specifications.
(3) Carefully install vapor/vacuum lines.The
vapor/vacuum lines and hoses must be firmly
connected. Also check the vapor/vacuum lines
at the LDP, LDP filter and EVAP canister purge
solenoid for damage or leaks. If a leak is
present, a Diagnostic Trouble Code (DTC) may
be set.
Fig. 23 LOCATION, EVAP CANISTERS
1 - LDP
2 - LDP MOUNTING BOLT
3 - ELEC. CONNEC.
4 - FILTER MOUNTING BOLT
5 - LDP FILTER
6 - CONNECTING HOSE
7 - EVAP CANISTER MOUNTING BRACKET
8 - EVAP CANISTERS (2)
25 - 22 EVAPORATIVE EMISSIONSDR
PCV VALVE (Continued)

CASE - NV271 - DESCRIPTION,
TRANSFER.........................21-447
CASE - NV271 - DIAGNOSIS AND
TESTING, TRANSFER.................21-448
CASE - NV271 - DISASSEMBLY,
TRANSFER.........................21-450
CASE - NV271 - INSPECTION, TRANSFER . 21-459
CASE - NV271 - INSTALLATION,
TRANSFER.........................21-473
CASE - NV271 - OPERATION, TRANSFER . 21-448
CASE - NV271 - REMOVAL, TRANSFER . . 21-450
CASE - NV273 - ASSEMBLY, TRANSFER . . 21-556
CASE - NV273 - CLEANING, TRANSFER . . 21-554
CASE - NV273 - DESCRIPTION,
TRANSFER.........................21-542
CASE - NV273 - DIAGNOSIS AND
TESTING, TRANSFER.................21-543
CASE - NV273 - DISASSEMBLY,
TRANSFER.........................21-544
CASE - NV273 - INSPECTION, TRANSFER . 21-554
CASE - NV273 - INSTALLATION,
TRANSFER.........................21-568
CASE - NV273 - OPERATION, TRANSFER . 21-543
CASE - NV273 - REMOVAL, TRANSFER . . 21-544
CASE BEARINGS - INSTALLATION,
DIFFERENTIAL.....3-106,3-134,3-161,3-48,3-75
CASE BEARINGS - REMOVAL,
DIFFERENTIAL.....3-105,3-134,3-161,3-48,3-75
CASE CONTROL MODULE -
DESCRIPTION, TRANSFER.............8E-16
CASE CONTROL MODULE - OPERATION,
TRANSFER..........................8E-16
CASE, NV241 GENII - TRANSFER.......21-438
CASE, NV241/NV243 - TRANSFER......21-439
CASE, NV243 - TRANSFER......21-505,21-506
CASE, NV244 GENII - TRANSFER.......21-535
CASE, NV271 - TRANSFER............21-473
CASE NV271/NV273, SPECIAL TOOLS -
TRANSFER...................21-474,21-569
CASE, NV273 - TRANSFER............21-568
CASE SKID PLATE - INSTALLATION,
TRANSFER..........................13-26
CASE SKID PLATE - REMOVAL,
TRANSFER..........................13-26
CASTER ADJUSTMENT - STANDARD
PROCEDURE, CAMBER..................2-4
CASTER AND TOE ADJUSTMENT -
STANDARD PROCEDURE, CAMBER........2-4
CATALYTIC CONVERTER - DESCRIPTION . . . 11-6
CATALYTIC CONVERTER - OPERATION.....11-6
CATCH - INSTALLATION, LATCH STRIKER
/ SECONDARY.......................23-48
CATCH - REMOVAL, LATCH STRIKER /
SECONDARY........................23-47
CAUTION - A/C SYSTEM...............24-43
CAUTION, HALF SHAFT.................3-20
CAUTION, INTERIOR..................23-62
CENTER - DESCRIPTION, ELECTRONIC
VEHICLE INFO.......................8M-7
CENTER - DIAGNOSIS AND TESTING,
ELECTRONIC VEHICLE INFORMATION.....8M-8
CENTER - INSTALLATION, ELECTRONIC
VEHICLE INFO.......................8M-9
CENTER & LEFT OUTBOARD -
INSTALLATION......................8O-50
CENTER & LEFT OUTBOARD - REMOVAL
. . 8O-48
CENTER - OPERATION, ELECTRONIC
VEHICLE INFO
.......................8M-7
CENTER - REMOVAL, ELECTRONIC
VEHICLE INFO
.......................8M-9
CENTER ANCHOR & RIGHT OUTBOARD -
INSTALLATION
......................8O-50
CENTER ANCHOR & RIGHT OUTBOARD -
REMOVAL
..........................8O-49
CENTER ARMREST / SEAT BACK -
INSTALLATION
.......................23-77
CENTER ARMREST / SEAT BACK -
REMOVAL
..........................23-76
CENTER BEARING - ADJUSTMENTS
........3-9
CENTER BEARING - INSTALLATION
........3-9
CENTER BEARING - REMOVAL
............3-9
CENTER BEZEL - INSTALLATION,
INSTRUMENT PANEL
..................23-57
CENTER BEZEL - REMOVAL,
INSTRUMENT PANEL
..................23-57
CENTER HIGH MOUNTED STOP LAMP -
INSTALLATION
.......................8L-11CENTER HIGH MOUNTED STOP LAMP -
REMOVAL..........................8L-11
CENTER HIGH MOUNTED STOP LAMP
UNIT - INSTALLATION.................8L-11
CENTER HIGH MOUNTED STOP LAMP
UNIT - REMOVAL....................8L-11
CENTER PROGRAMMING - STANDARD
PROCEDURE, ELECTRONIC VEHICLE
INFORMATION.......................8M-8
CENTER SEAT - INSTALLATION..........23-76
CENTER SEAT - REMOVAL.............23-75
CENTER SEAT BACK HINGE -
INSTALLATION.......................23-79
CENTER SEAT BACK HINGE - REMOVAL . . . 23-78
CENTER SEAT BACK INERTIA HINGE
COVER - INSTALLATION...............23-77
CENTER SEAT BACK INERTIA HINGE
COVER - REMOVAL...................23-77
CENTER SEAT BACK LID - INSTALLATION . 23-79
CENTER SEAT BACK LID - REMOVAL.....23-79
CENTER SEAT BELT - INSTALLATION,
FRONT.............................8O-31
CENTER SEAT BELT - REMOVAL, FRONT . . 8O-30
CENTER SEAT BELT & RETRACTOR -
INSTALLATION, FRONT................8O-29
CENTER SEAT BELT & RETRACTOR -
INSTALLATION, REAR.................8O-45
CENTER SEAT BELT & RETRACTOR -
REMOVAL, FRONT....................8O-29
CENTER SEAT BELT & RETRACTOR -
REMOVAL, REAR....................8O-44
CENTER SEAT CUSHION - INSTALLATION . . . 23-79
CENTER SEAT CUSHION - REMOVAL.....23-79
CENTER SEAT CUSHION COVER -
INSTALLATION.......................23-79
CENTER SEAT CUSHION COVER -
REMOVAL..........................23-79
CENTERING - STANDARD PROCEDURE,
CLOCKSPRING......................8O-19
CERTIFICATION LABEL - DESCRIPTION,
VEHICLE.........................Intro.-11
CHAIN COVER(S) - INSTALLATION,
TIMING BELT....................9-171,9-81
CHAIN COVER(S) - REMOVAL, TIMING
BELT ..........................9-170,9-81
CHAIN WEAR - STANDARD PROCEDURE,
MEASURING TIMING..................9-167
CHAIN WEAR, STANDARD PROCEDURE -
MEASURING TIMING...................9-77
CHAIN/TENSIONER - DESCRIPTION,
TIMING............................9-229
CHAIN/TENSIONER - OPERATION,
TIMING............................9-229
CHANNEL - INSTALLATION, GLASS RUN . . 23-22,
23-31
CHANNEL - REMOVAL, GLASS RUN . 23-21,23-30
CHARGE - STANDARD PROCEDURE,
REFRIGERANT SYSTEM...............24-47
CHARGE AIR COOLER AND PLUMBING -
CLEANING..........................11-17
CHARGE AIR COOLER AND PLUMBING -
DESCRIPTION.......................11-16
CHARGE AIR COOLER AND PLUMBING -
INSPECTION........................11-17
CHARGE AIR COOLER AND PLUMBING -
INSTALLATION.......................11-17
CHARGE AIR COOLER AND PLUMBING -
OPERATION
.........................11-16
CHARGE AIR COOLER AND PLUMBING -
REMOVAL
..........................11-17
CHARGE AIR COOLER SYSTEM - LEAKS
- DIAGNOSIS AND TESTING
............11-16
CHARGING - DESCRIPTION
.............8F-19
CHARGING - OPERATION
..............8F-19
CHARGING - STANDARD PROCEDURE,
BATTERY
............................8F-8
CHARGING SYSTEM - DIAGNOSIS AND
TESTING
...........................8F-19
CHARGING SYSTEM - SPECIFICATIONS,
TORQUE - GENERATOR
................8F-20
CHART - SPECIFICATIONS, TORQUE
........5-8
CHART, SPECIFICATIONS - TORQUE
.......5-46
CHART, SPECIFICATIONS - TORQUE
.....19-19,
19-23,19-35,19-42
CHART, SPECIFICATIONS - TORQUE
. . 2-10,2-29,
2-42
CHART, SPECIFICATIONS - TORQUE
......22-13CHARTS - DIAGNOSIS AND TESTING,
DIAGNOSIS........................21-145
CHARTS - DIAGNOSIS AND TESTING,
SMOKE DIAGNOSIS...................9-236
CHECK - STANDARD PROCEDURE,
COOLANT LEVEL......................7-17
CHECK - STANDARD PROCEDURE, FLUID
LEVEL......................21-202,21-366
CHECK - STANDARD PROCEDURE, OIL
PUMP VOLUME.....................21-387
CHECK CABLE - INSTALLATION.........23-15
CHECK CABLE - REMOVAL.............23-15
CHECK GAUGES INDICATOR -
DESCRIPTION.......................8J-21
CHECK GAUGES INDICATOR -
OPERATION.........................8J-21
CHECK VALVE - DESCRIPTION...........8R-7
CHECK VALVE - INSTALLATION..........8R-8
CHECK VALVE - OPERATION.............8R-8
CHECK VALVE - REMOVAL..............8R-8
CHILD RESTRAINT ANCHOR -
DESCRIPTION.......................8O-15
CHILD RESTRAINT ANCHOR -
INSTALLATION......................8O-18
CHILD RESTRAINT ANCHOR -
OPERATION.........................8O-17
CHILD RESTRAINT ANCHOR - REMOVAL . . 8O-17
CHIME WARNING SYSTEM -
DESCRIPTION........................8B-1
CHIME WARNING SYSTEM - DIAGNOSIS
AND TESTING........................8B-3
CHIME WARNING SYSTEM - OPERATION . . . 8B-1
CIGAR LIGHTER OUTLET -
DESCRIPTION.....................8W-97-2
CIGAR LIGHTER OUTLET - DIAGNOSIS
AND TESTING.....................8W-97-2
CIGAR LIGHTER OUTLET - OPERATION . 8W-97-2
CIRCUIT - DIAGNOSIS AND TESTING,
AMBIENT TEMPERATURE SENSOR......8M-10
CIRCUIT - OPERATION, FUEL DRAIN.....14-67
CIRCUIT ACTUATION TEST MODE -
DESCRIPTION........................25-1
CIRCUIT FUNCTIONS - DESCRIPTION . . 8W-01-6
CIRCUIT INFORMATION - DESCRIPTION . 8W-01-5
CIRCUIT SENSE - DESCRIPTION,
IGNITION...........................8E-10
CIRCUIT SENSE - OPERATION, IGNITION . . 8E-11
CIRCUITS - OPERATION, NON-
MONITORED.........................25-8
CLAMPS - DESCRIPTION, HOSE...........7-3
CLAMPS - OPERATION, HOSE.............7-5
CLEANING/REVERSE FLUSHING -
STANDARD PROCEDURE, COOLING
SYSTEM............................7-17
CLEARANCE - STANDARD PROCEDURE,
CONNECTING ROD BEARING AND
CRANKSHAFT JOURNAL...............9-272
CLEARANCE - STANDARD PROCEDURE,
MAIN BEARING......................9-274
CLEARANCE LAMP - INSTALLATION, CAB . 8L-12
CLEARANCE LAMP - REMOVAL, CAB.....8L-11
CLOCKSPRING - DESCRIPTION.........8O-18
CLOCKSPRING - INSTALLATION.........8O-21
CLOCKSPRING - OPERATION...........8O-19
CLOCKSPRING - REMOVAL............8O-20
CLOCKSPRING CENTERING - STANDARD
PROCEDURE........................8O-19
CLUSTER - ASSEMBLY, INSTRUMENT....8J-15
CLUSTER - DESCRIPTION, INSTRUMENT . . . 8J-2
CLUSTER - DIAGNOSIS AND TESTING,
INSTRUMENT........................8J-10
CLUSTER - DISASSEMBLY, INSTRUMENT . . 8J-14
CLUSTER - INSTALLATION, INSTRUMENT . 8J-16
CLUSTER - OPERATION, INSTRUMENT.....8J-6
CLUSTER - REMOVAL, INSTRUMENT.....8J-14
CLUSTER BEZEL - INSTALLATION........23-49
CLUSTER BEZEL - REMOVAL...........23-49
CLUTCH - 5.9L DIESEL - DESCRIPTION,
FAN DRIVE VISCOUS...................7-52
CLUTCH - 5.9L DIESEL - OPERATION,
FAN DRIVE VISCOUS...................7-52
CLUTCH - ASSEMBLY, FRONT..........21-207
CLUTCH - ASSEMBLY, LOW/REVERSE . . . 21-385
CLUTCH - ASSEMBLY, REAR
...........21-249
CLUTCH - CLEANING, LOW/REVERSE
....21-385
CLUTCH - CLEANING, REAR
...........21-248
CLUTCH - DESCRIPTION, FRONT
.......21-205
CLUTCH - DESCRIPTION, OVERDRIVE
. . . 21-217
6 INDEXDR
Description Group-Page Description Group-Page Description Group-Page