length INFINITI QX4 2001 Factory Owner's Manual

Multiport Fuel Injection (MFI) System
DESCRIPTIONNBEC0014Input/Output Signal ChartNBEC0014S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed (POS signal)
Fuel injec-
tion & mix-
ture ratio
controlInjectors Crankshaft position sensor (REF) Engine speed (REF signal)
Camshaft position sensor (PHASE) Piston position
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen sensor 1 (front) Density of oxygen in exhaust gas
Throttle position sensorThrottle position
Throttle valve idle position
Park/neutral position (PNP) switch Gear position
Vehicle speed sensor Vehicle speed
Ignition switch Start signal
Air conditioner switch Air conditioner operation
Knock sensor Engine knocking condition
Battery Battery voltage
Absolute pressure sensor Ambient air barometric pressure
Power steering oil pressure switch Power steering operation
Heated oxygen sensor 2 (rear)* Density of oxygen in exhaust gas
*: Under normal conditions, this sensor is not for engine control operation.
Basic Multiport Fuel Injection SystemNBEC0014S02The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor and the mass air
flow sensor.
Various Fuel Injection Increase/Decrease CompensationNBEC0014S03In addition, the amount of fuel injected is compensated to improve engine performance under various oper-
ating conditions as listed below.

IDuring warm-up
IWhen starting the engine
IDuring acceleration
IHot-engine operation
IWhen selector lever is changed from ªNº to ªDº
IHigh-load, high-speed operation

IDuring deceleration
IDuring high engine speed operation
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Multiport Fuel Injection (MFI) System
EC-28

DescriptionNBEC0596SYSTEM DESCRIPTIONNBEC0596S01
Sensor Input Signal to ECMECM func-
tionActuator
Mass air flow sensor Amount of intake air
VIAS con-
trolVIAS control solenoid valve Throttle position sensor Throttle position
Closed throttle position Throttle valve idle position
Ignition switch Start signal
Crankshaft position sensor (POS) Engine speed (POS signal)
Crankshaft position sensor (REF) Engine speed (REF signal)
Engine coolant temperature sensor Engine coolant temperature
SEF447Z
When the engine is running at low or medium speed, the power
valve is fully closed. Under this condition, the effective suction port
length is equivalent to the total length of the intake manifold collec-
tor's suction port including the intake valve. This long suction port
provides increased air intake which results in improved suction
efficiency and higher torque generation.
The surge tank and one-way valve are provided. When engine is
running at high speed, the ECM sends the signal to the VIAS con-
trol solenoid valve. This signal introduces the intake manifold
vacuum into the power valve actuator and therefore opens the
power valve to two suction passages together in the collector.
Under this condition, the effective port length is equivalent to the
length of the suction port provided independently for each cylinder.
This shortened port length results in enhanced engine output with
reduced suction resistance under high speeds.
VARIABLE INDUCTION AIR CONTROL SYSTEM (VIAS)
Description
EC-610

SEF375Z
Component DescriptionNBEC0383The fuel injector is a small, precise solenoid valve. When the ECM
supplies a ground to the injector circuit, the coil in the injector is
energized. The energized coil pulls the needle valve back and
allows fuel to flow through the injector into the intake manifold. The
amount of fuel injected depends upon the injection pulse duration.
Pulse duration is the length of time the injector remains open. The
ECM controls the injection pulse duration based on engine fuel
needs.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0384Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
INJ PULSE-B2
INJ PULSE-B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.4 - 3.2 msec
2,000 rpm 1.9 - 2.8 msec
B/FUEL SCHDL dittoIdle 2.0 - 3.2 msec
2,000 rpm 1.4 - 2.6 msec
ECM Terminals and Reference ValueNBEC0685Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
101
102
103
104
105
107R/B
L/W
R/W
PU/R
R/Y
R/LInjector No. 1
Injector No. 5
Injector No. 2
Injector No. 6
Injector No. 3
Injector No. 4[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
INJECTOR
Component Description
EC-616

XENON HEADLAMP=NBEL0188S07Xenon type headlamp is adopted to the low beam headlamps. Xenon bulbs do not use a filament. Instead,
they produce light when a high voltage current is passed between two tungsten electrodes through a mixture
of xenon (an inert gas) and certain other metal halides. In addition to added lighting power, electronic control
of the power supply gives the headlamps stable quality and tone color.
Following are some of the many advantage of the xenon type headlamp.
IThe light produced by the headlamps is white color approximating sunlight that is easy on the eyes.
ILight output is nearly double that of halogen headlamps, affording increased area of illumination.
IThe light features a high relative spectral distribution at wavelengths to the human eye is most sensitive,
which means that even in the rain, more light is reflected back from the road surface toward the vehicle,
for added visibility.
IPower consumption is approximately 25 percent less than halogen headlamps, reducing battery load.
SEL571X
HEADLAMP (FOR USA) Ð XENON TYPE Ð
System Description (Cont'd)
EL-34

SEM038F
SEM003F
CONNECTING ROD BEND AND TORSIONNBEM0027S04Bend:
Limit 0.15 mm (0.0059 in)
per 100 mm (3.94 in) length
Torsion:
Limit 0.30 mm (0.0118 in)
per 100 mm (3.94 in) length
If it exceeds the limit, replace connecting rod assembly.
SEM123C
CYLINDER BLOCK DISTORTION AND WEARNBEM0027S05IClean upper surface of cylinder block.
Use a reliable straightedge and feeler gauge to check the flat-
ness of cylinder block surface.
Check along six positions shown in the figure.
Distortion limit: 0.10 mm (0.0039 in)
IIf out of specification, resurface it. The limit for cylinder block
resurfacing is determined by cylinder head resurfacing in
engine.
Resurfacing limit:
Amount of cylinder head resurfacing is ªAº.
Amount of cylinder block resurfacing is ªBº.
The maximum limit is as follows:
A + B = 0.2 mm (0.008 in)
Nominal cylinder block height from crankshaft center:
214.95 - 215.05 mm (8.4626 - 8.4665 in)
Refer to SDS (EM-81).
IIf necessary, replace cylinder block.
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CYLINDER BLOCK
Inspection (Cont'd)
EM-65

ValveNBEM0032VALVENBEM0032S01Unit: mm (in)
SEM188
Valve head diameter ªDºIntake 37.0 - 37.3 (1.4567 - 1.4685)
Exhaust 31.2 - 31.5 (1.228 - 1.240)
Valve length ªLºIntake 96.12 - 96.62 (3.7842 - 3.8039)
Exhaust 93.65 - 94.15 (3.6870 - 3.7067)
Valve stem diameter ªdºIntake 5.965 - 5.980 (0.2348 - 0.2354)
Exhaust 5.945 - 5.960 (0.2341 - 0.2346)
Valve seat angle ªaºIntake
45É15¢- 45É45¢
Exhaust
Valve margin ªTºIntake 1.15 - 1.45 (0.0453 - 0.0571)
Exhaust 1.45 - 1.75 (0.0571 - 0.0689)
Valve margin ªTº limitMore than 0.5 (0.020)
Valve stem end surface grinding limit Less than 0.2 (0.008)
VALVE CLEARANCENBEM0032S02Unit: mm (in)
Cold Hot* (reference data)
Intake 0.26 - 0.34 (0.010 - 0.013) 0.304 - 0.416 (0.012 - 0.016)
Exhaust 0.29 - 0.37 (0.011 - 0.015) 0.308 - 0.432 (0.012 - 0.017)
*: Approximately 80ÉC (176ÉF)
AVAILABLE SHIMSNBEM0032S03
Thickness mm (in) Identification mark
2.32 (0.0913) 232
2.33 (0.0917) 233
2.34 (0.0921) 234
2.35 (0.0925) 235
2.36 (0.0929) 236
2.37 (0.0933) 237
2.38 (0.0937) 238
2.39 (0.0941) 239
2.40 (0.0945) 240
2.41 (0.0949) 241
SERVICE DATA AND SPECIFICATIONS (SDS)
Valve
EM-76

VALVE GUIDENBEM0032S06Unit: mm (in)
SEM950E
Standard Service
Valve guide Outer diameter 10.023 - 10.034 (0.3946 - 0.3950) 10.223 - 10.234 (0.4025 - 0.4029)
Valve guide Inner diameter (Finished size) 6.000 - 6.018 (0.2362 - 0.2369)
Cylinder head valve guide hole diameter 9.975 - 9.996 (0.3927 - 0.3935) 10.175 - 10.196 (0.4006 - 0.4014)
Interference fit of valve guide 0.027 - 0.059 (0.0011 - 0.0023)
Standard Max. tolerance
Stem to guide clearanceIntake 0.020 - 0.053 (0.0008 - 0.0021) 0.08 (0.0031)
Exhaust 0.040 - 0.073 (0.0016 - 0.0029) 0.1 (0.004)
Valve deflection limitIntake Ð 0.24 (0.0094)
Exhaust Ð 0.28 (0.0110)
Projection length ªLº12.6 - 12.8 (0.496 - 0.504)
Valve SeatNBEM0033Unit: mm (in)
SEM021EB
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SERVICE DATA AND SPECIFICATIONS (SDS)
Valve (Cont'd)
EM-79

Do not place the vehicle on flammable material. Keep flammable
material off the exhaust pipe and the three way catalyst.
SMA019D
PRECAUTIONS FOR HOSESNBGI0001S10Hose Removal and InstallationNBGI0001S1001ITo prevent damage to rubber hose, do not pry off rubber hose
with tapered tool or screwdriver.
SMA020D
ITo reinstall the rubber hose securely, make sure of hose inser-
tion length and clamp orientation. (If tube is equipped with
hose stopper, insert rubber hose into tube until it butts up
against hose stopper.)
SMA021D
Hose ClampingNBGI0001S1002IIf old rubber hose is re-used, install hose clamp in its original
position (at the indentation where the old clamp was). If there
is a trace of tube bulging left on the old rubber hose, align
rubber hose at that position.
IDiscard old clamps; replace with new ones.
SMA022D
IAfter installing leaf spring clamps, apply force to them in the
direction of the arrow, tightening rubber hose equally all
around.
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PRECAUTIONS
Precautions (Cont'd)
GI-7

SGI136A
ENGINE SERIAL NUMBERNBGI0007S0203
MGI042A
AUTOMATIC TRANSMISSION NUMBERNBGI0007S0204
MGI043A
TRANSFER SERIAL NUMBERNBGI0007S0205
DimensionsNBGI0007S03Unit: mm (in)
Wagon
VQ35DE
Overall length 4,650 (183.1)
Overall width 1,840 (72.4)
Overall height1,730 (68.1)
1,795 (70.7)*
Front tread 1,540 (60.6)
Rear tread 1,545 (60.8)
Wheelbase 2,700 (106.3)
*: With luggage rack
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IDENTIFICATION INFORMATION
Identification Number (Cont'd)
GI-43

Both High- and Low-pressure Sides are Too Low.NBHA0032S04
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.
AC353A
IThere is a big temperature
difference between
receiver drier outlet and
inlet. Outlet temperature is
extremely low.
ILiquid tank inlet and
expansion valve are
frosted.Compressor discharge
capacity does not change.
(Compressor stroke is set at
maximum.)IReplace liquid tank.
ICheck lubricant for con-
tamination.
ITemperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.
IExpansion valve inlet may
be frosted.
ITemperature difference
occurs somewhere in high-
pressure sideHigh-pressure pipe located
between receiver drier and
expansion valve is clogged.ICheck and repair malfunc-
tioning parts.
ICheck lubricant for con-
tamination.
IExpansion valve and liquid
tank are warm or only cool
when touched.Low refrigerant charge
"
Leaking fittings or compo-
nentsCheck refrigerant for leaks.
Refer to ªChecking Refriger-
ant Leaksº, HA-155.
There is a big temperature
difference between expan-
sion valve inlet and outlet
while the valve itself is
frosted.Expansion valve closes a
little compared with the
specification.
"
1. Improper expansion valve
adjustment
2. Malfunctioning thermal
valve
3. Outlet and inlet may be
clogged.IRemove foreign particles
by using compressed air.
ICheck lubricant for con-
tamination.
An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.Low-pressure pipe is clogged
or crushed.ICheck and repair malfunc-
tioning parts.
ICheck lubricant for con-
tamination.
Air flow volume is not
enough or is too low.Evaporator is frozen.
"
Compressor discharge
capacity does not change.
(Compressor stroke is set at
maximum length.)Replace compressor.
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TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-119