The proportional purge solenoid operates at a fre-
quency of 200hz and is controlled by an engine con-
troller circuit that senses the current being applied
to the proportional purge solenoid and then adjusts
that current to achieve the desired purge flow. The
proportional purge solenoid controls the purge rate of
fuel vapors from the vapor canister and fuel tank to
the engine intake manifold.
PRESSURE-VACUUM FILLER CAP
CAUTION: Remove the fuel filler cap to relieve fuel
tank pressure. The cap must be removed prior to
disconnecting any fuel system component or ser-
vicing the fuel tank.
A pressure-vacuum relief cap seals the fuel tank
(Fig. 3). Tightening the cap on the fuel filler tube
forms a seal between them. The relief valves in the
cap are a safety feature. They prevent possible exces-
sive pressure or vacuum in the tank. Excessive fuel
tank pressure could be caused by a malfunction in
the system or damage to the vent lines.
The seal between the cap and filler tube breaks
when the cap is removed and relieves fuel tank pres-
sure.
If the filler cap needs replacement, only use the
correct part.
LEAK DETECTION PUMP
The leak detection pump 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.
Immediately after a cold start, when the engine
temperature is 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 posi-
tion. 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 assem-
bly from reaching full travel. After the brief initial-
ization 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-ener-
gized, 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.
Fig. 2 Proportional Purge Solenoid
Fig. 3 Pressure Vacuum Filler Cap
25 - 14
EMISSION CONTROL SYSTEMS
NS
DESCRIPTION AND OPERATION (Continued)
Summary of Contents for 1998 Voyager
Page 8: ...FASTENER IDENTIFICATION NS INTRODUCTION 5 GENERAL INFORMATION Continued ...
Page 9: ...FASTENER STRENGTH 6 INTRODUCTION NS GENERAL INFORMATION Continued ...
Page 11: ...METRIC CONVERSION 8 INTRODUCTION NS GENERAL INFORMATION Continued ...
Page 12: ...TORQUE SPECIFICATIONS NS INTRODUCTION 9 GENERAL INFORMATION Continued ...
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Page 93: ...RED BRAKE WARNING LAMP FUNCTION NS BRAKES 5 11 DIAGNOSIS AND TESTING Continued ...
Page 94: ...POWER BRAKE SYSTEM DIAGNOSTICS 5 12 BRAKES NS DIAGNOSIS AND TESTING Continued ...
Page 95: ...VEHICLE ROAD TEST BRAKE NOISE NS BRAKES 5 13 DIAGNOSIS AND TESTING Continued ...
Page 222: ...COOLING SYSTEM DIAGNOSIS 7 8 COOLING SYSTEM NS DIAGNOSIS AND TESTING Continued ...
Page 223: ...NS COOLING SYSTEM 7 9 DIAGNOSIS AND TESTING Continued ...
Page 224: ...7 10 COOLING SYSTEM NS DIAGNOSIS AND TESTING Continued ...
Page 225: ...NS COOLING SYSTEM 7 11 DIAGNOSIS AND TESTING Continued ...
Page 226: ...7 12 COOLING SYSTEM NS DIAGNOSIS AND TESTING Continued ...
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Page 289: ...CHARGING SYSTEM SCHEMATIC TYPICAL NS CHARGING SYSTEM 8C 3 DIAGNOSIS AND TESTING Continued ...
Page 291: ...CHARGING SYSTEM TEST NS CHARGING SYSTEM 8C 5 DIAGNOSIS AND TESTING Continued ...
Page 292: ...OVERCHARGE TEST 8C 6 CHARGING SYSTEM NS DIAGNOSIS AND TESTING Continued ...
Page 294: ...VOLTAGE DROP TEST 8C 8 CHARGING SYSTEM NS ...
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Page 377: ...NS GS INSTRUMENT PANEL AND SYSTEMS 8E 5 DIAGNOSIS AND TESTING Continued ...
Page 378: ...8E 6 INSTRUMENT PANEL AND SYSTEMS NS GS DIAGNOSIS AND TESTING Continued ...
Page 379: ...NS GS INSTRUMENT PANEL AND SYSTEMS 8E 7 DIAGNOSIS AND TESTING Continued ...
Page 380: ...8E 8 INSTRUMENT PANEL AND SYSTEMS NS GS DIAGNOSIS AND TESTING Continued ...
Page 381: ...NS GS INSTRUMENT PANEL AND SYSTEMS 8E 9 DIAGNOSIS AND TESTING Continued ...
Page 382: ...8E 10 INSTRUMENT PANEL AND SYSTEMS NS GS DIAGNOSIS AND TESTING Continued ...
Page 383: ...NS GS INSTRUMENT PANEL AND SYSTEMS 8E 11 DIAGNOSIS AND TESTING Continued ...
Page 384: ...8E 12 INSTRUMENT PANEL AND SYSTEMS NS GS DIAGNOSIS AND TESTING Continued ...
Page 385: ...NS GS INSTRUMENT PANEL AND SYSTEMS 8E 13 DIAGNOSIS AND TESTING Continued ...
Page 386: ...8E 14 INSTRUMENT PANEL AND SYSTEMS NS GS DIAGNOSIS AND TESTING Continued ...
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Page 559: ...SPECIAL TOOLS SPECIAL TOOL Degausser 6029 NS OVERHEAD CONSOLE 8V 9 ...
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Page 564: ...8W 01 2 8W 01 GENERAL INFORMATION NS GS DESCRIPTION AND OPERATION Continued ...
Page 565: ...NS GS 8W 01 GENERAL INFORMATION 8W 01 3 DESCRIPTION AND OPERATION Continued ...
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Page 1220: ...Fig 3 Lubrication Lines 9 42 ENGINE NS GS DESCRIPTION AND OPERATION Continued ...
Page 1224: ...ENGINE DIAGNOSIS MECHANICAL CONT 9 46 ENGINE NS GS DIAGNOSIS AND TESTING Continued ...
Page 1286: ...Fig 5 Front Crossmember Dimensions 13 6 FRAME AND BUMPERS NS SPECIFICATIONS Continued ...
Page 1287: ...Fig 6 Engine Compartment Top View NS FRAME AND BUMPERS 13 7 SPECIFICATIONS Continued ...
Page 1289: ...Fig 8 Full Vehicle Bottom View NS FRAME AND BUMPERS 13 9 SPECIFICATIONS Continued ...
Page 1291: ...Fig 11 Body Side Openings NS FRAME AND BUMPERS 13 11 SPECIFICATIONS Continued ...
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Page 1302: ...FUEL PRESSURE BELOW SPECIFICATIONS 14 8 FUEL SYSTEM NS DIAGNOSIS AND TESTING Continued ...
Page 1304: ...FUEL INJECTOR DIAGNOSIS 14 10 FUEL SYSTEM NS DIAGNOSIS AND TESTING Continued ...
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Page 1479: ...Diagnosis Guide NS TRANSAXLE AND POWER TRANSFER UNIT 21 5 DIAGNOSIS AND TESTING Continued ...
Page 1480: ...Diagnosis Guide 21 6 TRANSAXLE AND POWER TRANSFER UNIT NS DIAGNOSIS AND TESTING Continued ...
Page 1481: ...Diagnosis Guide NS TRANSAXLE AND POWER TRANSFER UNIT 21 7 DIAGNOSIS AND TESTING Continued ...
Page 1482: ...Diagnosis Guide 21 8 TRANSAXLE AND POWER TRANSFER UNIT NS DIAGNOSIS AND TESTING Continued ...
Page 1483: ...Diagnosis Guide NS TRANSAXLE AND POWER TRANSFER UNIT 21 9 DIAGNOSIS AND TESTING Continued ...
Page 1484: ...Diagnosis Guide 21 10 TRANSAXLE AND POWER TRANSFER UNIT NS DIAGNOSIS AND TESTING Continued ...
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Page 1486: ...Diagnosis Guide 21 12 TRANSAXLE AND POWER TRANSFER UNIT NS DIAGNOSIS AND TESTING Continued ...
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Page 1723: ...LEAD CORRECTION CHART NS TIRES AND WHEELS 22 5 DIAGNOSIS AND TESTING Continued ...
Page 1726: ...SPECIFICATIONS TIRE SPECIFICATIONS 22 8 TIRES AND WHEELS NS ...
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