fuel INFINITI FX35 2007 Service Manual

EC-692
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ENGINE CONTROL SYSTEM
Revision: 2006 July 2007 FX35/FX45
Multiport Fuel Injection (MFI) SystemNBS004JO
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The 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 the crankshaft position sensor (POS), camshaft position
sensor (PHASE) and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.


During warm-up

When starting the engine

During acceleration

Hot-engine operation

When selector lever is changed from N to D

High-load, high-speed operation


During deceleration

During high engine speed operation
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*
3
Piston position
Fuel injection
& mixture ratio
control Fuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Battery Battery voltage*
3
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit) VDC/TCS operation command*
2
Air conditioner switch Air conditioner operation
Wheel sensor Vehicle speed*
2

ENGINE CONTROL SYSTEM EC-693
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Revision: 2006 July 2007 FX35/FX45
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses A/F
sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage signal. For more information about A/F sensor 1, refer to
EC-901
. This maintains the mixture ratio within the range of stoichiometric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.

Deceleration and acceleration

High-load, high-speed operation

Malfunction of A/F sensor 1 or its circuit

Insufficient activation of A/F sensor 1 at low engine coolant temperature

High engine coolant temperature

During warm-up

After shifting from N to D

When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
PBIB3020E

EC-694
[VK45DE]
ENGINE CONTROL SYSTEM
Revision: 2006 July 2007 FX35/FX45
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all eight cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The eight fuel injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration, operation of the engine at excessively high speeds or oper-
ation of the vehicle at excessively high speeds.
Electronic Ignition (EI) SystemNBS004JP
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Firing order: 1 - 8 - 7 - 3 - 6 - 5 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor (PHASE) sig-
nal. Computing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is revised by the ECM according to the other data stored in
the ECM.

At starting

During warm-up

At idle

At low battery voltage
PBIB0122E
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*
2
Piston position
Ignition timing
control Power transistor
Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Battery Battery voltage*
2
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Wheel sensor Vehicle speed*
1

ENGINE CONTROL SYSTEM EC-695
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Revision: 2006 July 2007 FX35/FX45

During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Fuel Cut Control (at No Load and High Engine Speed)NBS004JQ
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,400 rpm under no load (for example, the selector lever position is neutral and
engine speed is over 1,400 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off var-
ies based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,000 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under Multiport Fuel Injection (MFI) System, EC-692
.
Sensor Input Signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut con-
trol Fuel injector
Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed
Wheel sensor Vehicle speed*

EC-700
[VK45DE]
EVAPORATIVE EMISSION SYSTEM
Revision: 2006 July 2007 FX35/FX45
EVAPORATIVE EMISSION SYSTEMPFP:14950
DescriptionNBS0041A
SYSTEM DESCRIPTION
The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume control solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating.
PBIB1631E

EVAPORATIVE EMISSION SYSTEM EC-703
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Revision: 2006 July 2007 FX35/FX45
Component InspectionNBS0041B
EVAP CANISTER
Check EVAP canister as follows:
1. Block port B .
2. Blow air into port A and check that it flows freely out of port C .
3. Release blocked port B .
4. Apply vacuum pressure to port B and check that vacuum pres-
sure exists at the ports A and C .
5. Block port A and B .
6. Apply pressure to port C and check that there is no leakage.
FUEL TANK VACUUM RELIEF VALVE (BUILT INTO FUEL FILLER CAP)
1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
3. If out of specification, replace fuel filler cap as an assembly.
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incor-
rect fuel filler cap is used, the MIL may come on.
EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-1078 .
FUEL TANK TEMPERATURE SENSOR
Refer to EC-1008 .
EVAP CANISTER VENT CONTROL VALVE
Refer to EC-1085 .
EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-1101 .
PBIB1044E
SEF445Y
Pressure:
15.3 - 20.0 kPa (0.156 - 0.204 kg/cm2 , 2.22
- 2.90 psi)
Va c u u m : − 6.0 to −3.3 kPa ( −0.061 to −0.034 kg/cm
2 ,
− 0.87 to −0.48 psi)
SEF943S

EC-704
[VK45DE]
EVAPORATIVE EMISSION SYSTEM
Revision: 2006 July 2007 FX35/FX45
EVAP SERVICE PORT
Positive pressure is delivered to the EVAP system through the EVAP
service port. If fuel vapor leakage in the EVAP system occurs, use a
leak detector to locate the leak.
Removal and InstallationNBS0041C
EVAP CANISTER
Tighten EVAP canister as shown in the figure.
EVAP CANISTER VENT CONTROL VALVE
1. Turn EVAP canister vent control valve counterclockwise.
2. Remove the EVAP canister vent control valve.
Always replace O-ring with a new one.
How to Detect Fuel Vapor LeakageNBS0041D
CAUTION:

Do not use compressed air or a high pressure pump.

Do not exceed 4.12 kPa (0.042 kg/cm2 , 0.6 psi) of pressure in EVAP system.
NOTE:

Do not start engine.

Improper installation of EVAP service port adapter to the EVAP service port may cause a leak.
SEF462UA
PBIB1628E
PBIB1030E

ON BOARD REFUELING VAPOR RECOVERY (ORVR) EC-707
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Revision: 2006 July 2007 FX35/FX45
ON BOARD REFUELING VAPOR RECOVERY (ORVR)PFP:00032
System DescriptionNBS0041E
From the beginning of refueling, the air and vapor inside the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspections below, be sure to observe the following:

Put a “CAUTION: FLAMMABLE” sign in workshop.

Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.

Be sure to furnish the workshop with a CO2 fire extinguisher.
CAUTION:

Before removing fuel line parts, carry out the following procedures:
–Put drained fuel in an explosion-proof container and put lid on securely.
–Release fuel pressure from fuel line. Refer to EC-747, "FUEL PRESSURE RELEASE" .
–Disconnect battery ground cable.

Always replace O-ring when the fuel gauge retainer is removed.

Do not kink or twist hose and tube when they are installed.

Do not tighten hose and clamps excessively to avoid damaging hoses.

After installation, run engine and check for fuel leaks at connection.

Do not attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, resulting in fuel spray and possibly a fire.
PBIB1068E

EC-708
[VK45DE]
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
Revision: 2006 July 2007 FX35/FX45
Diagnostic ProcedureNBS0041F
SYMPTOM: FUEL ODOR FROM EVAP CANISTER IS STRONG.
1. CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
The weight should be less than 2.1 kg (4.6 lb).
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2. CHECK IF EVAP CANISTER SATURATED WITH WATER
Does water drain from the EVAP canister?
Ye s o r N o
Yes >> GO TO 3.
No >> GO TO 5.
3. REPLACE EVAP CANISTER
Replace EVAP canister with a new one.
>> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the EVAP hose between EVAP canister and vehicle frame for clogging or poor connection.
>> Repair or replace EVAP hose.
5. CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-710, "
Component Inspection" .
OK or NG
OK >> INSPECTION END
NG >> Replace refueling EVAP vapor cut valve with fuel tank.
PBIB1031E

ON BOARD REFUELING VAPOR RECOVERY (ORVR) EC-709
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Revision: 2006 July 2007 FX35/FX45
SYMPTOM: CANNOT REFUEL/FUEL ODOR FROM THE FUEL FILLER OPENING IS STRONG
WHILE REFUELING.
1. CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
The weight should be less than 2.1 kg (4.6 lb).
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2. CHECK IF EVAP CANISTER SATURATED WITH WATER
Does water drain from the EVAP canister?
Ye s o r N o
Ye s > > G O T O 3 .
No >> GO TO 5.
3. REPLACE EVAP CANISTER
Replace EVAP canister with a new one.
>> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the EVAP hose between EVAP canister and vehicle frame for clogging or poor connection.
>> Repair or replace EVAP hose.
5. CHECK VENT HOSES AND VENT TUBES
Check hoses and tubes between EVAP canister and refueling control valve for clogging, kink, looseness and
improper connection.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace hoses and tubes.
6. CHECK FILLER NECK TUBE
Check recirculation line for clogging, dents and cracks.
OK or NG
OK >> GO TO 7.
NG >> Replace filler neck tube.
PBIB1031E