1998 DODGE RAM 1500 Engine cranks no start

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)

RELAY - DESCRIPTION, STARTER
MOTOR............................8F-35
RELAY - DESCRIPTION, TRANSMISSION
CONTROL.........................21-405
RELAY - DESCRIPTION, WIPER
HIGH/LOW..........................8R-20
RELAY - DESCRIPTION, WIPER ON/OFF . . . 8R-24
RELAY - DIAGNOSIS AND TESTING,
PARK LAMP.........................8L-20
RELAY - DIAGNOSIS AND TESTING,
STARTER ...........................8F-36
RELAY - DIAGNOSIS AND TESTING,
WIPER HIGH/LOW...................8R-21
RELAY - DIAGNOSIS AND TESTING,
WIPER ON/OFF......................8R-25
RELAY - INSTALLATION, A/C
COMPRESSOR CLUTCH...............24-14
RELAY - INSTALLATION, FOG LAMP......8L-13
RELAY - INSTALLATION, FUEL HEATER . . . 14-53
RELAY - INSTALLATION, FUEL PUMP.....14-28
RELAY - INSTALLATION, INTAKE AIR
HEATER ............................14-82
RELAY - INSTALLATION, PARK LAMP.....8L-21
RELAY - INSTALLATION, REAR WINDOW
DEFOGGER..........................8G-4
RELAY - INSTALLATION, STARTER
MOTOR............................8F-37
RELAY - INSTALLATION, WIPER
HIGH/LOW..........................8R-22
RELAY - INSTALLATION, WIPER ON/OFF . . 8R-26
RELAY - OPERATION, A/C COMPRESSOR
CLUTCH.............................24-13
RELAY - OPERATION, FOG LAMP........8L-13
RELAY - OPERATION, FUEL HEATER......14-52
RELAY - OPERATION, FUEL PUMP.......14-27
RELAY - OPERATION, INTAKE AIR
HEATER ............................14-82
RELAY - OPERATION, PARK LAMP.......8L-20
RELAY - OPERATION, REAR WINDOW
DEFOGGER..........................8G-3
RELAY - OPERATION, STARTER MOTOR . . . 8F-36
RELAY - OPERATION, TRANSMISSION
CONTROL.........................21-405
RELAY - OPERATION, WIPER HIGH/LOW . . 8R-20
RELAY - OPERATION, WIPER ON/OFF....8R-25
RELAY - REMOVAL, A/C COMPRESSOR
CLUTCH............................24-14
RELAY - REMOVAL, FOG LAMP.........8L-13
RELAY - REMOVAL, FUEL HEATER.......14-52
RELAY - REMOVAL, FUEL PUMP........14-28
RELAY - REMOVAL, INTAKE AIR HEATER . . 14-82
RELAY - REMOVAL, PARK LAMP........8L-21
RELAY - REMOVAL, REAR WINDOW
DEFOGGER..........................8G-3
RELAY - REMOVAL, STARTER MOTOR....8F-37
RELAY - REMOVAL, WIPER HIGH/LOW . . . 8R-21
RELAY - REMOVAL, WIPER ON/OFF......8R-26
RELAYS - DIAGNOSIS AND TESTING,
ASD AND FUEL PUMP..................8I-5
RELEASE - INSTALLATION, TILT LEVER
KNOB..............................19-16
RELEASE - REMOVAL, TILT LEVER KNOB . . 19-16
RELEASE - STANDARD PROCEDURE,
FUEL SYSTEM PRESSURE..............14-2
RELEASE BEARING - INSTALLATION,
CLUTCH
.............................6-10
RELEASE BEARING - REMOVAL, CLUTCH
...6-9
RELEASE CABLE/HANDLE ASSEMBLY -
INSTALLATION, LATCH
................23-47
RELEASE CABLE/HANDLE ASSEMBLY -
REMOVAL, LATCH
....................23-47
RELEASE HANDLE - INSTALLATION
.......5-44
RELEASE HANDLE - REMOVAL
...........5-44
RELEASE HANDLE/LATCH REMOTE -
INSTALLATION
.......................23-17
RELEASE HANDLE/LATCH REMOTE -
REMOVAL
..........................23-17
RELIEF VALVE - CLEANING, OIL
PRESSURE
.........................9-294
RELIEF VALVE - DESCRIPTION, HIGH
PRESSURE
.........................24-48
RELIEF VALVE - INSPECTION, OIL
PRESSURE
.........................9-294
RELIEF VALVE - INSTALLATION, OIL
PRESSURE
.........................9-294
RELIEF VALVE - OPERATION, HIGH
PRESSURE
.........................24-48RELIEF VALVE - REMOVAL, OIL
PRESSURE.........................9-294
REMINDER PROGRAMMING -
STANDARD PROCEDURE, ENHANCED
SEATBELT..........................8J-35
REMOTE - INSTALLATION, RELEASE
HANDLE/LATCH......................23-17
REMOTE - REMOVAL, RELEASE
HANDLE/LATCH......................23-17
REMOTE KEYLESS ENTRY MODULE -
DESCRIPTION........................8N-7
REMOTE KEYLESS ENTRY MODULE -
DIAGNOSIS AND TESTING..............8N-7
REMOTE KEYLESS ENTRY MODULE -
INSTALLATION.......................8N-8
REMOTE KEYLESS ENTRY MODULE -
OPERATION..........................8N-7
REMOTE KEYLESS ENTRY MODULE -
REMOVAL...........................8N-7
REMOTE KEYLESS ENTRY
TRANSMITTER - DIAGNOSIS AND
TESTING............................8N-8
REMOTE KEYLESS ENTRY
TRANSMITTER - SPECIFICATIONS........8N-9
REMOTE SWITCHES - DESCRIPTION.....8A-10
REMOTE SWITCHES - DIAGNOSIS AND
TESTING...........................8A-11
REMOTE SWITCHES - INSTALLATION.....8A-12
REMOTE SWITCHES - OPERATION.......8A-11
REMOTE SWITCHES - REMOVAL........8A-12
REMOVAL/INSTALLATION, REMOVAL.....25-13
REMOVAL/INSTALLATION, REMOVAL.....14-52,
14-57,14-66
REPAIR - DESCRIPTION, THREADED
HOLE.............................Intro.-8
REPAIR - STANDARD PROCEDURE,
ALUMINUM THREAD...........21-158,21-318
REPAIR - STANDARD PROCEDURE, CAM
BORE..............................9-267
REPAIR - STANDARD PROCEDURE,
CYLINDER BORE.....................9-265
REPAIR - STANDARD PROCEDURE, GRID
LINE AND TERMINAL..................8G-4
REPAIR - STANDARD PROCEDURE,
HYDROFORM FENDER RAIL............13-11
REPAIR - STANDARD PROCEDURE,
PLASTIC BODY PANEL.................23-3
REPAIR DAMAGED OR WORN THREADS
- STANDARD PROCEDURE . 9-190,9-240,9-9,9-94
REPAIRING LEAKS - STANDARD
PROCEDURE........................22-10
REQUIREMENTS - DESCRIPTION,
ENGINE COOLING SYSTEM..............24-1
REQUIREMENTS - DIESEL ENGINE -
DESCRIPTION, FUEL....................0-1
RESERVOIR - DESCRIPTION, VACUUM....8P-9
RESERVOIR - DESCRIPTION, WASHER . . . 8R-14
RESERVOIR - DIAGNOSIS AND TESTING,
VACUUM............................8P-9
RESERVOIR - INSTALLATION...........19-47
RESERVOIR - INSTALLATION, FLUID......5-24
RESERVOIR - INSTALLATION, VACUUM . . . 8P-10
RESERVOIR - OPERATION, VACUUM......8P-9
RESERVOIR - OPERATION, WASHER.....8R-15
RESERVOIR - REMOVAL...............19-47
RESERVOIR - REMOVAL, FLUID..........5-23
RESERVOIR - REMOVAL, VACUUM........8P-9
RESERVOIR TO COOLER -
INSTALLATION, RETURN HOSE.....19-44,19-45
RESERVOIR TO COOLER - REMOVAL,
RETURN HOSE.................19-44,19-45
RESISTANCE, 3.7L V-6 - IGNITION COIL....8I-5
RESISTANCE, 4.7L V-8 - IGNITION COIL....8I-5
RESISTANCE, 5.7L V-8 - IGNITION COIL....8I-5
RESISTANCE, SPECIFICATIONS - SPARK
PLUG CABLE.........................8I-4
RESISTOR BLOCK - DESCRIPTION,
BLOWER MOTOR....................24-18
RESISTOR BLOCK - DIAGNOSIS AND
TESTING, BLOWER MOTOR
............24-19
RESISTOR BLOCK - INSTALLATION,
BLOWER MOTOR
....................24-19
RESISTOR BLOCK - OPERATION,
BLOWER MOTOR
....................24-18
RESISTOR BLOCK - REMOVAL, BLOWER
MOTOR
............................24-19
RESTRAINT ANCHOR - DESCRIPTION,
CHILD
.............................8O-15RESTRAINT ANCHOR - INSTALLATION,
CHILD.............................8O-18
RESTRAINT ANCHOR - OPERATION,
CHILD.............................8O-17
RESTRAINT ANCHOR - REMOVAL, CHILD . 8O-17
RESTRAINT DEPLOYMENT - STANDARD
PROCEDURE, SERVICE AFTER A
SUPPLEMENTAL......................8O-7
RESTRAINT SYSTEM - DIAGNOSIS AND
TESTING, SUPPLEMENTAL..............8O-6
RESTRAINT SYSTEM - WARNINGS.......8O-5
RESTRAINTS - DESCRIPTION............8O-2
RESTRAINTS - OPERATION.............8O-4
RESTRAINTS - STANDARD PROCEDURE,
HANDLING NON-DEPLOYED
SUPPLEMENTAL......................8O-6
RETAINER - ASSEMBLY, OVERRUNNING
CLUTCH CAM/OVERDRIVE PISTON......21-237
RETAINER - CLEANING, OVERRUNNING
CLUTCH CAM/OVERDRIVE PISTON......21-236
RETAINER - DESCRIPTION,
OVERRUNNING CLUTCH CAM/
OVERDRIVE PISTON.................21-236
RETAINER - DISASSEMBLY,
OVERRUNNING CLUTCH CAM/
OVERDRIVE PISTON.................21-236
RETAINER - INSPECTION,
OVERRUNNING CLUTCH CAM/
OVERDRIVE PISTON.................21-237
RETAINER - INSTALLATION, A-PILLAR
WEATHERSTRIP.....................23-91
RETAINER - INSTALLATION,
CRANKSHAFT REAR OIL SEAL.....9-210,9-277
RETAINER - INSTALLATION, DRIP RAIL
WEATHERSTRIP.....................23-92
RETAINER - OPERATION, OVERRUNNING
CLUTCH CAM/OVERDRIVE PISTON......21-236
RETAINER - REMOVAL, A-PILLAR
WEATHERSTRIP.....................23-91
RETAINER - REMOVAL, CRANKSHAFT
REAR OIL SEAL.................9-209,9-277
RETAINER - REMOVAL, DRIP RAIL
WEATHERSTRIP.....................23-92
RETAINER/BULKHEAD - ASSEMBLY, 4C . . 21-363
RETAINER/BULKHEAD - DISASSEMBLY,
4C ...............................21-362
RETRACTOR - DESCRIPTION,
AUTOMATIC LOCKING.................8O-14
RETRACTOR - INSTALLATION, FRONT
CENTER SEAT BELT..................8O-29
RETRACTOR - INSTALLATION, REAR
CENTER SEAT BELT..................8O-45
RETRACTOR - INSTALLATION, REAR
OUTBOARD SEAT BELT................8O-47
RETRACTOR - OPERATION, AUTOMATIC
LOCKING...........................8O-14
RETRACTOR - REMOVAL, FRONT
CENTER SEAT BELT..................8O-29
RETRACTOR - REMOVAL, REAR CENTER
SEAT BELT .........................8O-44
RETRACTOR - REMOVAL, REAR
OUTBOARD SEAT BELT................8O-46
RETURN - DESCRIPTION, SENSOR.......8E-10
RETURN HOSE - GEAR TO COOLER -
INSTALLATION..................19-44,19-45
RETURN HOSE - GEAR TO COOLER -
REMOVAL.....................19-44,19-45
RETURN HOSE - INSTALLATION, HEATER . 24-65
RETURN HOSE - REMOVAL, HEATER.....24-64
RETURN HOSE - RESERVOIR TO
COOLER - INSTALLATION.........19-44,19-45
RETURN HOSE - RESERVOIR TO
COOLER - REMOVAL.............19-44,19-45
REVOLUTIONS PER MILE,
SPECIFICATIONS - TIRE...............22-10
RFE TRANSMISSION, SPECIAL TOOLS . . . 21-359
RING - INSTALLATION, PINION
GEAR/RING GEAR/TONE.....3-108,3-137,3-164
RING - REMOVAL, PINION GEAR/RING
GEAR/TONE...............3-106,3-134,3-162
RING FITTING - STANDARD
PROCEDURE, PISTON . . . 9-142,9-213,9-284,9-53
RINGS - ASSEMBLY, WITH INJECTED
......3-13
RINGS - ASSEMBLY, WITH SNAP
.........3-12
RINGS - DISASSEMBLY, WITH INJECTED
. . . 3-11
RINGS - DISASSEMBLY, WITH SNAP
......3-10
RKE TRANSMITTER BATTERIES -
STANDARD PROCEDURE
...............8N-8
DRINDEX 27
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