vin INFINITI QX4 2001 Factory Service Manual

SEM948E
ReplacementNBEM0015CAUTION:
When removing the oil pans, oil pump assembly and timing
chain from engine, first remove the camshaft position sensor
(PHASE), CVTC sensor and the crankshaft position sensors
(REF)/(POS) from the assembly.
Be careful not to damage sensor edges.
VALVE OIL SEALNBEM0015S011. Remove timing chain. Refer to ªRemoval, EM-23.
2. Remove camshaft brackets and camshaft. Refer to
ªDisassemblyº, EM-41.
3. Remove valve lifters and shims.
4. Remove valve spring with Tool.
5. Reinstall any parts removed in reverse order of removal.
Before removing valve spring, fix valve as follows.
Method A:
Piston concerned should be set at TDC to prevent valve
from falling.
SEM826E
Method B:
Remove spark plug, then install air hose adapter into
spark plug hole and apply air pressure to hold valves in
place. Apply a pressure of 490 kPa (5 kg/cm
2, 71 psi).
SEM983D
Method C:
Install spark plug with suitable washer into spark plug
hole from combustion chamber side.
SEM827E
6. Remove valve oil seal.
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OIL SEAL
Replacement
EM-35

SEM444G
14. Remove RH and LH camshaft chain tensioners from cylinder
head.
SEM859E
SEM860E
15. Remove cylinder head bolts.
ICylinder head bolts should be loosened in two or three
steps.
IA warped or cracked cylinder head could result from
removing in incorrect order.
SEM863E
16. Remove cylinder head.
DisassemblyNBEM0043Remove valve component parts.
Refer to EM-35, ªVALVE OIL SEALº.
ICheck the clearance before removing the valve guide. Refer to
EM-43, ªVALVE GUIDE CLEARANCEº.
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CYLINDER HEAD
Removal (Cont'd)
EM-41

Removal and InstallationNBEM0042WARNING:
ISituate vehicle on a flat and solid surface.
IPlace chocks at front and back of rear wheels.
IDo not remove engine until exhaust system has com-
pletely cooled off. Otherwise, you may burn yourself
and/or fire may break out in fuel line.
IFor safety during subsequent steps, the tension of wires
should be slackened against the engine.
IBefore disconnecting fuel hose, release fuel pressure
from fuel line.
Refer to EC-39, ªFuel Pressure Releaseº.
IBefore removing front axle from transmission, place
safety stands under designated front supporting points.
Refer to GI section for lifting points and towing.
IBe sure to hoist engine and transmission in a safe man-
ner.
IFor engines not equipped with engine slingers, attach
proper slingers and bolts described in PARTS CATALOG.
CAUTION:
IWhen lifting engine, be careful not to strike adjacent parts,
especially accelerator wire casing, brake lines, and brake
master cylinder.
IIn hoisting the engine, always use engine slingers in a
safe manner.
IBefore separating engine and transmission, remove
crankshaft position sensor (POS) from the assembly.
IAlways take extra care not to damage edge of crankshaft
position sensor (POS), or ring gear teeth.GI
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ENGINE ASSEMBLY
Removal and Installation
EM-57

SEM965A
7. Remove pistons with connecting rods.
IWhen disassembling piston and connecting rod, remove snap
ring first, then heat piston to 60 to 70ÉC (140 to 158ÉF).
8. Remove rear oil seal retainer.
CAUTION:
IWhen piston rings are not replaced, make sure that piston
rings are mounted in their original positions.
IWhen replacing piston rings, if there is no punchmark,
install with either side up.
SEM842E
9. Loosen bolts in numerical order as shown and remove main
bearing beam, bearing cap and crankshaft.
IBefore removing bearing beam and bearing cap, measure
crankshaft end play. Refer to EM-71.
IBolts should be loosened in two or three steps.
SEM454G
10. Remove oil jets.
AEM023
InspectionNBEM0027PISTON AND PISTON PIN CLEARANCENBEM0027S011. Measure inner diameter of piston pin hole ªdpº.
Standard diameter ªdpº:
Grade No. 0
21.993 - 21.999 mm (0.8659 - 0.8661 in)
Grade No. 1
21.999 - 22.005 mm (0.8661 - 0.8663 in)
AEM024
2. Measure outer diameter of piston pin ªDpº.
Standard diameter ªDpº:
Grade No. 0
21.989 - 21.995 mm (0.8657 - 0.8659 in)
Grade No. 1
21.995 - 22.001 mm (0.8659 - 0.8662 in)
3. Calculate interference fit of piston pin to piston.
Dp þ dp = 0.002 - 0.006 mm (0.0001 - 0.0002 in)
If it exceeds the above value, replace piston assembly with pin.
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CYLINDER BLOCK
Disassembly (Cont'd)
EM-63

Removal and InstallationNBFE0002CAUTION:
IWhen removing accelerator wire, make a mark to indicate lock nut's initial position.
ICheck that throttle valve opens fully when accelerator pedal is fully depressed. Also check that it
returns to idle position when pedal is released.
ICheck accelerator control parts for improper contact with any adjacent parts.
IWhen connecting accelerator wire, be careful not to twist or scratch its inner wire.
IRefer to EL-240, ªAUTOMATIC SPEED CONTROL DEVICEº for ASCD wire adjustment.
SFE635A
SEF793W
SFE249AE
Adjusting Accelerator WireNBFE00031. Remove the vacuum hose connected to the throttle opener.
2. Connect suitable vacuum hose to vacuum pump as shown left.
3. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81
inHg)] until the throttle drum becomes free from the rod of the
throttle opener.
Make sure that there is clearance between the throttle
drum and rod.
If NG, refer to EC-101, ªBasic Inspectionº.
If OK, go to following step.
4. Loosen lock nut.
5. Tighten accelerator adjusting nut until throttle drum starts to
move.
6. From that position, turn back adjusting nut 1.5 to 2 turns, and
secure lock nut.
7. Release vacuum from the throttle opener.
8. Remove vacuum pump and vacuum hose from the throttle
opener.
9. Reinstall the original vacuum hose to the throttle opener
securely.
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ACCELERATOR CONTROL SYSTEM
Removal and Installation
FE-3

Removal and InstallationNBFE0004WARNING:
When replacing fuel line parts, be sure to observe the follow-
ing:
IPut a ªCAUTION: INFLAMMABLEº sign in workshop.
IDo not smoke while servicing fuel system. Keep open
flames and sparks away from work area.
IBe sure to furnish the workshop with a CO
2fire extin-
guisher.
CAUTION:
IBefore removing fuel line parts, carry out the following
procedures:
a) Put drained fuel in an explosion-proof container and put
lid on securely.
b) Release fuel pressure from fuel line. Refer to MA-16,
ªChanging Fuel Filterº.
c) Disconnect battery ground cable.
IAlways replace O-ring with new ones.
IDo not kink or twist hose and tube when they are installed.
IDo not tighten hose clamps excessively to avoid damag-
ing hoses.
IWhen installing fuel check valve, be careful of its desig-
nated direction. Refer to EC-32, ªEVAPORATIVE EMIS-
SION SYSTEMº.
IAfter installation, run engine and check for fuel leaks at
connections.
FUEL SYSTEM
Removal and Installation
FE-4

SGI285
GENERAL PRECAUTIONSNBGI0001S02IDo not operate the engine for an extended period of time
without proper exhaust ventilation.
Keep the work area well ventilated and free of any inflammable
materials. Special care should be taken when handling any
inflammable or poisonous materials, such as gasoline, refrig-
erant gas, etc. When working in a pit or other enclosed area,
be sure to properly ventilate the area before working with haz-
ardous materials.
Do not smoke while working on the vehicle.
SGI231
IBefore jacking up the vehicle, apply wheel chocks or other tire
blocks to the wheels to prevent the vehicle from moving. After
jacking up the vehicle, support the vehicle weight with safety
stands at the points designated for proper lifting before work-
ing on the vehicle.
These operations should be done on a level surface.
IWhen removing a heavy component such as the engine or
transaxle/transmission, be careful not to lose your balance and
drop it. Also, do not allow it to strike adjacent parts, especially
the brake tubes and master cylinder.
SEF289H
IBefore starting repairs which do not require battery power:
Turn off ignition switch.
Disconnect the negative battery terminal.
SGI233
ITo prevent serious burns:
Avoid contact with hot metal parts.
Do not remove the radiator cap when the engine is hot.
SGI234
IBefore servicing the vehicle:
Protect fenders, upholstery and carpeting with appropriate cov-
ers.
Take caution that keys, buckles or buttons do not scratch paint.
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PRECAUTIONS
Precautions (Cont'd)
GI-5

SEL272V
4. While moving the connector, check whether the male terminal
can be easily inserted or not.
SEL273V
IIf the male terminal can be easily inserted into the female
terminal, replace the female terminal.
SEL275V
Waterproof Connector InspectionNBGI0011S04If water enters the connector, it can short interior circuits. This may
lead to intermittent problems.
Check the following items to maintain the original waterproof char-
acteristics.
RUBBER SEAL INSPECTIONNBGI0011S0401IMost waterproof connectors are provided with a rubber seal
between the male and female connectors. If the seal is
missing, the waterproof performance may not meet specifica-
tions.
IThe rubber seal may come off when connectors are discon-
nected. Whenever connectors are reconnected, make sure the
rubber seal is properly installed on either side of male or
female connector.
WIRE SEAL INSPECTIONNBGI0011S0402The wire seal must be installed on the wire insertion area of a
waterproof connector. Be sure that the seal is installed properly.
SEL330V
Terminal Lock InspectionNBGI0011S05Check for unlocked terminals by pulling wire at the end of connec-
tor. An unlocked terminal may create intermittent signals in the
circuit.
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HOW TO CHECK TERMINAL
How to Check Enlarged Contact Spring of Terminal (Cont'd)
GI-23

Incident Simulation TestsNBGI0004S02INTRODUCTIONNBGI0004S0201Sometimes the symptom is not present when the vehicle is brought
in for service. If possible, re-create the conditions present at the
time of the incident. Doing so may help avoid a No Trouble Found
Diagnosis. The following section illustrates ways to simulate the
conditions/environment under which the owner experiences an
electrical incident.
The section is broken into the six following topics:
IVehicle vibration
IHeat sensitive
IFreezing
IWater intrusion
IElectrical load
ICold or hot start up
Get a thorough description of the incident from the customer. It is
important for simulating the conditions of the problem.
VEHICLE VIBRATIONNBGI0004S0202The problem may occur or become worse while driving on a rough
road or when engine is vibrating (idle with A/C on). In such a case,
you will want to check for a vibration related condition. Refer to the
illustration below.
Connectors & Harness
Determine which connectors and wiring harness would affect the
electrical system you are inspecting.Gentlyshake each connec-
tor and harness while monitoring the system for the incident you
are trying to duplicate. This test may indicate a loose or poor elec-
trical connection.
Hint
Connectors can be exposed to moisture. It is possible to get a thin
film of corrosion on the connector terminals. A visual inspection
may not reveal this without disconnecting the connector. If the
problem occurs intermittently, perhaps the problem is caused by
corrosion. It is a good idea to disconnect, inspect and clean the
terminals on related connectors in the system.
Sensors & Relays
Gentlyapply a slight vibration to sensors and relays in the system
you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
SGI839
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HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests
GI-25

Engine Compartment
There are several reasons a vehicle or engine vibration could
cause an electrical complaint. Some of the things to check for are:
IConnectors not fully seated.
IWiring harness not long enough and is being stressed due to
engine vibrations or rocking.
IWires laying across brackets or moving components.
ILoose, dirty or corroded ground wires.
IWires routed too close to hot components.
To inspect components under the hood, start by verifying the integ-
rity of ground connections. (Refer to GROUND INSPECTION
described later.) First check that the system is properly grounded.
Then check for loose connection bygently shakingthe wiring or
components as previously explained. Using the wiring diagrams
inspect the wiring for continuity.
Behind The Instrument Panel
An improperly routed or improperly clamped harness can become
pinched during accessory installation. Vehicle vibration can aggra-
vate a harness which is routed along a bracket or near a screw.
Under Seating Areas
An unclamped or loose harness can cause wiring to be pinched by
seat components (such as slide guides) during vehicle vibration. If
the wiring runs under seating areas, inspect wire routing for pos-
sible damage or pinching.
SGI842
HEAT SENSITIVENBGI0004S0203The owner's problem may occur during hot weather or after car has
sat for a short time. In such cases you will want to check for a heat
sensitive condition.
To determine if an electrical component is heat sensitive, heat the
component with a heat gun or equivalent.
Do not heat components above 60ÉC (140ÉF).If incident occurs
while heating the unit, either replace or properly insulate the com-
ponent.
SGI843
FREEZINGNBGI0004S0204The customer may indicate the incident goes away after the car
warms up (winter time). The cause could be related to water freez-
ing somewhere in the wiring/electrical system.
There are two methods to check for this. The first is to arrange for
the owner to leave his car overnight. Make sure it will get cold
enough to demonstrate his complaint. Leave the car parked out-
side overnight. In the morning, do a quick and thorough diagnosis
of those electrical components which could be affected.
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests (Cont'd)
GI-26