2008 INFINITI FX35 fuel clog

ENGINE CONTROL SYSTEMEC-33
< SERVICE INFORMATION > [VQ35DE]
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(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 air fuel
ratio (A/F) sensor 1, refer to EC-220
. 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 thr ee way catalyst 1. Even if the switching characteris-
tics of air fuel ratio (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 air fuel ratio (A/F) sensor 1 or its circuit
 Insufficient activation of air fuel ratio (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 air fuel ratio (A/F)
sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to
the theoretical mixture ratio as possible. However, the bas ic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during 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 co mpared 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 compensati on used to maintain the mixture ratio at its theoretical
value. The signal from air fuel ratio (A/F) sensor 1 i ndicates whether the mixture ratio is RICH or LEAN com-
pared to the theoretical value. The signal then triggers a r eduction 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 ca rried 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.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycl e 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 six cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The six 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.
SEF179U
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ON BOARD REFUELING VAPOR RECOVERY (ORVR)EC-47
< SERVICE INFORMATION > [VQ35DE]
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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-48, "
Component Inspection".
OK or NG
OK >> INSPECTION END
NG >> Replace refueling EVAP vapor cut valve with fuel tank.
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 c ontrol 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 l ess 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.
PBIB1031E
PBIB1031E
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EC-48
< SERVICE INFORMATION >[VQ35DE]
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
>> 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 refue ling 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.
7.CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-48, "
Component Inspection".
OK or NG
OK >> GO TO 8.
NG >> Replace refueling EVAP vapor cut valve with fuel tank.
8.CHECK FUEL FILLER TUBE
Check filler neck tube and hose connected to the fuel tank for clogging, dents and cracks.
OK or NG
OK >> GO TO 9.
NG >> Replace fuel filler tube.
9.CHECK ONE-WAY FUEL VALVE-I
Check one-way valve for clogging.
OK or NG
OK >> GO TO 10.
NG >> Repair or replace one-way fuel valve with fuel tank.
10.CHECK ONE-WAY FUEL VALVE-II
1. Make sure that fuel is drained from the tank.
2. Remove fuel filler tube and hose.
3. Check one-way fuel valve for operation as follows. When a stick is inserted, the valve should open, when removing
stick it should close.
Do not drop any material into the tank.
OK or NG
OK >> INSPECTION END
NG >> Replace fuel filler tube or replace one-way fuel valve
with fuel tank.
Component InspectionINFOID:0000000001325910
REFUELING EVAP VAPOR CUT VALVE
SEF665U
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BASIC SERVICE PROCEDUREEC-87
< SERVICE INFORMATION > [VQ35DE]
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1.
Check that throttle valve is fully closed.
2. Check PCV valve operation.
3. Check that downstream of throttl e valve is free from air leakage.
4. When the above three items check out OK, engine component parts and their installation condi-
tion are questionable. Check and el iminate the cause of the incident.
It is useful to perform EC-131
.
5. If any of the following conditi ons occur after the engine has started, eliminate the cause of the
incident and perform Idle Air Vo lume Learning all over again:
 Engine stalls.
 Erroneous idle.
Fuel Pressure CheckINFOID:0000000001325926
FUEL PRESSURE RELEASE
With CONSULT-III
1. Turn ignition switch ON.
2. Perform “FUEL PRESSURE RELEASE” in “WORK SUPPORT” mode with CONSULT-III.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
Without CONSULT-III
1. Remove fuel pump fuse located in IPDM E/R.
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel pressure.
4. Turn ignition switch OFF.
5. Reinstall fuel pump fuse after servicing fuel system.
FUEL PRESSURE CHECK
CAUTION:
Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.
NOTE:
 Prepare pans or saucers under the disconnected fuel line because the fuel may spill out. The fuel
pressure cannot be completely released because S50 models do not have fuel return system.
 Use Fuel Pressure Gauge Kit (J-44321) to check fuel pressure.
1. Release fuel pressure to zero. Refer to “FUEL PRESSURE RELEASE”.
2. Install the inline fuel quick disconnected fitting between fuel damper and fuel injector tube.
3. Connect the fuel pressure test gauge (quick connector adapter hose) to the inline fuel quick disconnected fitting.
4. Turn ignition switch ON and check for fuel leakage.
5. Start engine and check for fuel leakage.
6. Read the indication of fuel pressure gauge.
7. If result is unsatisfactory, go to next step.
8. Check the following.  Fuel hoses and fuel tubes for clogging
 Fuel filter for clogging
PBIB1603E
At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)PBIB1571E
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EC-88
< SERVICE INFORMATION >[VQ35DE]
BASIC SERVICE PROCEDURE
 Fuel pump
 Fuel pressure regulator for clogging
If OK, replace fuel pressure regulator.
If NG, repair or replace.
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EC-134
< SERVICE INFORMATION >[VQ35DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
ely 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.
OK or NG
OK >> GO TO 17.
NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.
2.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 4.
NG (More than the SP value)>>GO TO 19.
3.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 6.
NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.
4.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Stop the engine.
2. Disconnect PCV hose, and then plug it.
3. Start engine.
4. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> GO TO 5.
NG >> GO TO 6.
5.CHANGE ENGINE OIL
1. Stop the engine.
2. Change engine oil. NOTE:
This symptom may occur when a large amount of gasoline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detec ted after changing engine oil or changing driving con-
dition.
>>INSPECTION END
6.CHECK FUEL PRESSURE
Check fuel pressure. (Refer to EC-87, "
Fuel Pressure Check".)
OK or NG
OK >> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to EC-87, "
Fuel Pressure Check". GO
TO 8.
NG (Fuel pressure is too low)>>GO TO 7.
7.DETECT MALFUNCTIONING PART
1. Check the following.
- Clogged and bent fuel hose and fuel tube
- Clogged fuel filter
- Fuel pump and its circuit (Refer to EC-558
.)
2. If NG, repair or replace the malfunctioning part. (Refer to EC-87, "
Fuel Pressure Check".)
If OK, replace fuel pressure regulator.
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-135
< SERVICE INFORMATION > [VQ35DE]
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>> GO TO 8.
8.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 9.
9.PERFORM POWER BALANCE TEST
1. Perform “POWER BALANCE ” in “ACTIVE TEST” mode.
2. Make sure that the each cylinder produces a momentary engine speed drop.
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10.DETECT MALFUNCTIONING PART
1. Check the following.
- Ignition coil and its circuit (Refer to EC-569
.)
- Fuel injector and its circuit (Refer to EC-552
.)
- Intake air leakage
- Low compression pressure (Refer to EM-100, "
On-Vehicle Service".)
2. If NG, repair or replace the malfunctioning part.
If OK, replace fuel injector. (It may be caus ed by leakage from fuel injector or clogging.)
>> GO TO 11.
11 .CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 12.
12.CHECK A/F SENSOR 1 FUNCTION
Perform all DTC Confirmation Proc edure related with A/F sensor 1.
 For DTC P0130, P0150, refer to EC-212, "
DTC Confirmation Procedure".
 For DTC P0131, P0151, refer to EC-220, "
DTC Confirmation Procedure".
 For DTC P0132, P0152, refer to EC-228, "
DTC Confirmation Procedure".
 For DTC P0133, P0153, refer to EC-236, "
DTC Confirmation Procedure".
 For DTC P2A00, P2A03, refer to EC-532, "
DTC Confirmation Procedure".
OK or NG
OK >> GO TO 15.
NG >> GO TO 13.
13.CHECK A/F SENSOR 1 CIRCUIT
Perform Diagnostic Procedure according to corresponding DTC.
>> GO TO 14.
14.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
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DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-281
< SERVICE INFORMATION > [VQ35DE]
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OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
 Fuel pump and circuit (Refer to EC-558
.)
 Fuel pressure regulator (Refer to EC-87, "
Fuel Pressure Check")
 Fuel lines (Refer to FL-3, "
Checking Fuel Line".)
 Fuel filter for clogging
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK (With CONSULT-III)>>GO TO 7.
OK (Without COUSULT-II)>>GO TO 8.
NG >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
ground. Refer to EC-175
.
7.CHECK FUNCTION OF FUEL INJECTOR
With CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Make sure that each circuit produces a momentary engine speed drop.
OK or NG
OK >> GO TO 10.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-552
.
8.CHECK FUNCTION OF FUEL INJECTOR-I
Without CONSULT-III
1. Turn ignition switch OFF. At idling: Approximately 350 kPa (3.57 kg/cm
2, 51 psi)
2.0 - 6.0 g·m/sec: at idling
7.0 - 20.0 g·m/sec: at 2,500 rpm
2.0 - 6.0 g·m/sec: at idling
7.0 - 20.0 g·m/sec: at 2,500 rpm
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