INFINITI QX4 2001 Factory Service Manual

NBEM0005
SEM472G
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
EM-8

NVH Troubleshooting Ð Engine NoiseNBEM0005S01Use the chart below to help you find the cause of the symptom.
1. Locate the area where noise occurs.
2. Confirm the type of noise.
3. Specify the operating condition of engine.
4. Check specified noise source.
If necessary, repair or replace these parts.
Location of
noiseType of
noiseOperating condition of engine
Source of
noiseCheck itemReference
page Before
warm-upAfter
warm-upWhen
startingWhen
idlingWhen
racingWhile
driving
To p o f
engine
Rocker
cover
Cylinder
headTicking or
clickingC A ÐA BÐTappet
noiseValve clearance EM-54
Rattle C A Ð A B CCamshaft
bearing
noiseCamshaft journal clear-
ance
Camshaft runoutEM-42, 42
Crankshaft
pulley
Cylinder
block
(Side of
engine)
Oil panSlap or
knockÐ A ÐB BÐPiston pin
noisePiston and piston pin
clearance
Connecting rod bush-
ing clearanceEM-63, 70
Slap or
rapA ÐÐBBAPiston slap
noisePiston-to-bore clear-
ance
Piston ring side clear-
ance
Piston ring end gap
Connecting rod bend
and torsionEM-64, 64,
65, 66
Knock A B C B B BConnect-
ing rod
bearing
noiseConnecting rod bush-
ing clearance (Small
end)
Connecting rod bearing
clearance (Big end)EM-70, 69
Knock A B Ð A B CMain bear-
ing noiseMain bearing oil clear-
ance
Crankshaft runoutEM-67, 67
Front of
engine
Timing
chain
coverTapping or
tickingA A ÐBBBTiming
chain and
chain ten-
sioner
noiseTiming chain cracks
and wear
Timing chain tensioner
operationEM-29, 20
Front of
engineSqueaking
or fizzingA B ÐBÐCOther
drive belts
(Sticking
or slipping)Drive belts deflectionMA section
(ªChecking
Drive
Beltsº,
ªENGINE
MAINTE-
NANCEº) Creaking A BABABOther
drive belts
(Slipping)Idler pulley bearing
operation
Squall
CreakA B ÐBABWater
pump
noiseWater pump operationLC section
(ªWater
Pump
Inspectionº,
ªENGINE
COOLING
SYSTEMº)
A: Closely related B: Related C: Sometimes related Ð: Not related
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NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NVH Troubleshooting Ð Engine Noise
EM-9

Removal and InstallationNBEM0006
SEM483G
1. Intake manifold collector support
2. Lower intake manifold collector
3. Fuel damper and fuel feed hose
assembly
4. Injector
5. Fuel tube assembly6. Fuel pressure regulator
7. Ignition coil with power transistor
8. Upper intake manifold collector
9. Intake manifold
10. Throttle body11. IACV-AAC valve
12. EVAP canister purge volume con-
trol solenoid valve
13. Swirl control valve
14. Variable induction air control valve
control actuator
OUTER COMPONENT PARTS
Removal and Installation
EM-10

SEM484GA
1. Heated oxygen sensor 1 (front)
(bank 1)
2. Heated oxygen sensor 1 (front)
(bank 2)
3. TWC (manifold)4. Thermostat with water inlet
5. Exhaust manifold
6. Thermal transmitter
7. Engine coolant temperature8. Water control valve
9. Water outlet housing
10. Cylinder block water outlet
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OUTER COMPONENT PARTS
Removal and Installation (Cont'd)
EM-11

SEM950F
TIGHTENING PROCEDURESNBEM0006S01Intake ManifoldNBEM0006S0101ITighten in numerical order shown in the figure.
1. Tighten all bolts and nuts to 5 to 10 N´m (0.5 to 1.0 kg-m, 44
to 86 in-lb).
2. Finally tighten all bolts and nuts to 26 to 31 N´m (2.7 to 3.2
kg-m, 20 to 23 ft-lb).
ITighten all bolts and nuts to the final torque, evenly dividing the
tightening into at least five steps.
SEM473G
Fuel TubeNBEM0006S0102ITighten in numerical order shown in the figure.
1. Tighten all bolts to 9.3 to 10.8 N´m (0.95 to 1.1 kg-m, 83 to 95
in-lb).
2. Then tighten all bolts to 21 to 26 N´m (2.1 to 2.7 kg-m, 15 to
20 ft-lb).
SEM474G
Fuel Pressure RegulatorNBEM0006S0103Tighten fuel pressure regulator to 2.9 to 3.8 N´m (0.3 to 0.39 kg-m,
26.0 to 33.9 in-lb).
ITighten screws evenly several times to have the fuel pres-
sure regulator tightened at the specified torque.
IAlways replace O-ring with new ones.
ILubricate O-ring with new engine oil.
SEM475G
Throttle BodyNBEM0006S0105ITighten in numerical order shown in the figure.
1. Tighten all bolts to 8.8 to 10.8 N´m (0.9 to 1.1 kg-m, 79 to 95
in-lb).
2. Then tighten all bolts to 18 to 21 N´m (1.8 to 2.2 kg-m, 13 to
15 ft-lb).
SEM476G
Upper Intake Manifold CollectorNBEM0006S0107Tighten bolts and nuts to 18 to 21 N´m (1.8 to 2.2 kg-m, 13 to 15
ft-lb) in numerical order shown in the figure.
OUTER COMPONENT PARTS
Removal and Installation (Cont'd)
EM-12

SEM477G
Lower Intake Manifold CollectorNBEM0006S0108Tighten bolts and nuts to 18 to 21 N´m (1.8 to 2.2 kg-m, 13 to 15
ft-lb) in numerical order shown in the figure.
SEM478G
SEM479G
Exhaust ManifoldNBEM0006S0109Tighten nuts to 28 to 32 N´m (2.9 to 3.3 kg-m, 21 to 24 ft-lb) in
numerical order shown in the figure.
SEM607G
TWC (Manifold)NBEM0006S0110IAlign the mating mark as shown for locating exhaust flange.
SEM609G
IInstall washer and mesh washer as shown.
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OUTER COMPONENT PARTS
Removal and Installation (Cont'd)
EM-13

NBEM0007
SEM480G
SEM481G
JEM482G
SEM387C
1. Warm up engine.
2. Turn ignition switch OFF.
3. Release fuel pressure.
Refer to EC-39, ªFuel Pressure Releaseº.
4. Remove engine cover and throttle wire.
5. Remove air duct with air cleaner case.
6. Remove harness connectors and harness brackets around
ignition coils.
7. Remove throttle body.
8. Disconnect ignition coil with power transistor harness
connectors, then remove ignition coils.
9. Remove all spark plugs.
IClean area around plug with compressed air before removing
the spark plug.
10. Attach a compression tester to No. 1 cylinder.
11. Depress accelerator pedal fully to keep throttle valve wide
open.
12. Crank engine and record highest gauge indication.
13. Repeat the measurement on each cylinder as shown above.
IAlways use a fully-charged battery to obtain specified
engine speed.
Unit: kPa (kg/cm2, psi)/rpm
Standard MinimumDifference limit between
cylinders
1,275 (13.0, 185)/300 981 (10.0, 142)/300 98 (1.0, 14)/300
14. If compression in one or more cylinders is low:
a. Pour a small amount of engine oil into cylinders through spark
plug holes.
b. Retest compression.
IIf adding oil helps compression, piston rings may be worn
or damaged. If so, replace piston rings after checking pis-
ton.
IIf pressure stays low, a valve may be sticking or seating
improperly. Inspect and repair valve and valve seat. (Refer
to SDS, EM-76 and EM-79.) If valve or valve seat is dam-
aged excessively, replace them.
IIf compression stays low in two cylinders that are next to
each other:
a) The cylinder head gasket may be leaking, or
b) Both cylinders may have valve component damage. Inspect
and repair as necessary.
15. Install parts in reverse order of removal.
16. Perform ªSelf-diagnosis Procedureº referring to EC-72, ªHow to
Erase DTCº if any DTC appears.
MEASUREMENT OF COMPRESSION PRESSURE
EM-14

ComponentsNBEM0008
SEM583G
RemovalNBEM0009WARNING:
IPlace vehicle on a flat and solid surface.
IYou should not remove oil pan until exhaust system and
cooling system have completely cooled off.
Otherwise, you may burn yourself and/or fire may break
out in the fuel line.
IWhen removing front engine mounting nuts, lift up slightly
engine for safety work.
CAUTION:
When removing the aluminum oil pan from engine, first
remove the crankshaft position sensors (POS and REF) from
the assembly.
Be careful not to damage sensor edges and signal plate teeth.
1. Remove front RH and LH wheels.
2. Remove battery.
3. Remove oil level gauge.
4. Remove engine undercover.
5. Remove suspension member stay.
6. Drain engine coolant from radiator drain plug.
7. Disconnect A/T oil cooler hoses.
8. Drain engine oil.
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OIL PAN
Components
EM-15

9. Remove the crankshaft position sensors (REF and POS).
10. Remove drive belts and idler pulley with bracket.
11. Remove power steering oil pump, then put it aside holding with
a suitable wire.
12. Remove alternator.
SEM605G
13. Install engine slingers.
14. Remove front propeller shaft. (4WD)
Refer to PD-6, ªRemoval and Installationº.
15. Remove exhaust front tube heat insulators, then remove rear
heat oxygen sensors.
16. Remove exhaust front tube from both sides.
Refer to FE-8, ªRemoval and Installationº.
17. Remove front final drive. (4WD)
Refer to PD-18, ªRemoval and Installationº.
18. Remove starter motor.
19. Disconnect oil pressure switch harness connector.
SEM528G
20. Loosen and disconnect the bolts fixing the steering column
assembly lower joint and the power steering gear.
SEM471G
21. Set a suitable transmission jack under the front suspension
member and hoist engine with engine slingers.
EMQ0357D
22. Remove front engine mounting nuts from both sides.
OIL PAN
Removal (Cont'd)
EM-16

SEM529G
SEM530G
23. Remove front suspension member bolts.
24. Lower the transmission jack carefully to secure clearance
between the oil pan and suspension member.
25. Remove A/T oil cooler tube.
26. Remove water hose and tube.
SEM469G
27. Remove the four engine-to-transmission bolts.
SEM463G
28. Remove aluminum oil pan bolts in numerical order.
SEM365E
29. Remove aluminum oil pan.
a. Insert tool between aluminum oil pan and cylinder block.
IBe careful not to damage aluminum mating surface.
IDo not insert screwdriver, or oil pan flange will be
deformed.
b. Slide tool by tapping its side with a hammer.
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OIL PAN
Removal (Cont'd)
EM-17