ENGINE DIAGNOSIS
INDEX
page
page
DIAGNOSIS AND TESTING
PRESSURE LEAKAGE TEST . . . . . . . . . . . . . . 8
CYLINDER COMPRESSION PRESSURE TEST . . 7
ENGINE DIAGNOSIS—MECHANICAL . . . . . . . . . 12
ENGINE DIAGNOSIS—PERFORMANCE . . . . . . 10
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 7
INSPECTION
(ENGINE OIL LEAKS IN GENERAL) . . . . . . . . . 8
INTAKE MANIFOLD LEAKAGE DIAGNOSIS . . . . . 7
LASH ADJUSTER (TAPPET)
NOISE DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . 8
DIAGNOSIS AND TESTING
GENERAL INFORMATION
Engine diagnosis is helpful in determining the
causes of malfunctions.
These malfunctions may be classified as either
mechanical (e.g., a strange noise), or performance
(e.g., engine idles rough and stalls).
Refer to the Service Diagnosis—Mechanical Chart
and the Service Diagnosis—Performance Chart, for
possible causes and corrections of malfunctions. Refer
to Group 14, Fuel System, for the fuel system diag-
nosis.
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can-
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following:
•
Cylinder Compression Pressure Test
•
Cylinder Combustion Pressure Leakage Test
•
Engine Cylinder Head Gasket Failure Diagnosis
•
Intake Manifold Leakage Diagnosis
INTAKE MANIFOLD LEAKAGE DIAGNOSIS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING:
USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water (Spray Bottle) at
the suspected leak area.
(3) If a change in RPM’S, the area of the suspected
leak has been found.
(4) Repair as required.
CYLINDER COMPRESSION PRESSURE TEST
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Check engine oil level and add oil if necessary.
(2)
Drive the vehicle until engine reaches normal
operating temperature. Select a route free from traf-
fic and other forms of congestion, observe all traffic
laws, and accelerate through the gears several times
briskly.
(3)
Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for abnor-
mal firing indicators fouled, hot, oily, etc. Record cyl-
inder number of spark plug for future reference.
(4)
Disconnect coil wire from distributor and
secure to good ground to prevent a spark from start-
ing a fire (Conventional Ignition System). For Direct
Ignition System DIS disconnect the coil connector.
(5)
Be sure throttle blade is fully open during the
compression check.
(6)
Insert compression gage adaptor into the #1
spark plug hole in cylinder head. Crank engine until
maximum pressure is reached on gage. Record this
pressure as #1 cylinder pressure.
(7) Repeat the previous step for all remaining cyl-
inders.
(8) Compression should not be less than (689kPa)
100 psi and not vary more than 25 percent from cyl-
inder to cylinder.
(9)
If one or more cylinders have abnormally low
compression pressures, repeat the compression test.
(10)
If the same cylinder or cylinders repeat an
abnormally low reading on the second compression
test, it could indicate the existence of a problem in
the cylinder in question. The recommended com-
pression pressures are to be used only as a
guide to diagnosing engine problems. An engine
should not be disassembled to determine the
NS
ENGINE
9 - 7
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 ...
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Page 384: ...8E 12 INSTRUMENT PANEL AND SYSTEMS NS GS DIAGNOSIS AND TESTING Continued ...
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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 ...
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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 ...
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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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