2001 NISSAN PICK-UP stop start

Mixture Ratio Feedback Control (Closed loop control)NEEC0014S04
SEC303D
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission con-
trol. The three way catalyst can then better reduce CO, HC and NOx emissions. This system uses a heated
oxygen sensor 1 in the exhaust manifold to monitor if the engine operation is rich or lean. The ECM adjusts
the injection pulse width according to the sensor voltage signal. For more information about the heated oxy-
gen sensor 1, refer to EC-3213. 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. Even if the switching characteris-
tics of the heated oxygen sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from the
heated oxygen sensor 2.
Open Loop ControlNEEC0014S05The 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 heated oxygen sensor 1 or its circuit
+Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature
+High engine coolant temperature
+During warm-up
+When starting the engine
Mixture Ratio Self-learning ControlNEEC0014S06The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxy-
gen 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 basic mixture ratio is not necessarily controlled as
originally designed. Both manufacturing differences (i.e., mass air flow sensor hot film) and characteristic
changes during operation (i.e., 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 ªinjection pulse durationº to automatically compensate for the difference between
the two ratios.
ªFuel trimº refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
ªShort term fuel trimº is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from the heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN com-
pared to the theoretical 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.
ªLong term fuel trimº 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.
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
Multiport Fuel Injection (MFI) System
EC-3025

If results are unsatisfactory, perform Fuel Pressure Regulator
Check, EC-3034.
SEF718B
Fuel Pressure Regulator CheckNEEC00261. Stop engine and disconnect fuel pressure regulator vacuum
hose from intake manifold.
2. Plug intake manifold with a rubber cap.
3. Connect variable vacuum source to fuel pressure regulator.
4. Start engine and read indication of fuel pressure gauge as
vacuum is changed.
Fuel pressure should decrease as vacuum increases. If results
are unsatisfactory, replace fuel pressure regulator.
SEF319V
SEF116V
SEF117V
Injector
REMOVAL AND INSTALLATIONNEEC00271. Release fuel pressure to zero.
2. Remove injector tube assembly with injectors from intake
manifold.
3. Remove injectors from injector tube assembly.
+Push injector tail piece.
+Do not pull on the connector.
4. Install injector to fuel tube assembly.
a. Clean exterior of injector tail piece.
b. Use new O-rings.
Always replace O-rings with new ones.
Lubricate O-rings with a smear of engine oil.
5. Install injectors with fuel tube assembly to intake manifold.
Tighten in numerical order shown in the figure.
a. First, tighten all bolts to 9.3 to 10.8 N´m (0.95 to 1.1 kg-m, 6.9
to 8.0 ft-lb).
b. Then, tighten all bolts to 21 to 26 N´m (2.1 to 2.7 kg-m, 15 to
20 ft-lb).
6. Install fuel hoses to fuel tube assembly.
7. Reinstall any parts removed in reverse order of removal.
CAUTION:
After properly connecting injectors to fuel tube assembly,
check connections for fuel leakage.
BASIC SERVICE PROCEDUREKA24DE (EURO OBD)
Fuel Pressure Check
EC-3034

12 PREPARATION FOR IDLE SPEED ADJUSTING
With CONSULT-II
1. Select ªIGNITION TIMING ADJº in ªWORK SUPPORTº mode.
2. Touch ªSTARTº.
PEF546N
Without CONSULT-II
1. Stop engine and disconnect throttle position sensor harness connector.
SEF265S
2. Start engine.
©GO TO 6.
BASIC SERVICE PROCEDUREKA24DE (EURO OBD)
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment
EC-3045

15 CHECK HEATED OXYGEN SENSOR 1 SIGNAL
With CONSULT-II
1. Replace heated oxygen sensor 1.
2. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
3. Maintain engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.). Check that the
monitor fluctuates between ªLEANº and ªRICHº more than five times during 10 seconds.
1 cycle: RICH®LEAN®RICH
2 cycles: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1.
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 50 and ground.
6. Make sure that voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000 rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©GO TO 12.
NG©GO TO 16.
16 DETECT MALFUNCTIONING PART
1. Connect heated oxygen sensor 1 harness connector to heated oxygen sensor 1.
2. Check fuel pressure regulator. Refer to EC-3034.
3. Check mass air flow sensor and its circuit.
Refer to EC-3143, EC-3151.
4. Check injector and its circuit.
Refer to EC-3369.
Clean or replace if necessary.
5. Check engine coolant temperature sensor and its circuit. Refer to EC-3165.
6. Check ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 12.
+If a vehicle contains a part which is operating outside of design specifications with no MI
illumination, the part shall not be replaced prior to emission testing unless it is determined that
the part has been tampered with or abused in such a way that the diagnostic system cannot rea-
sonably be expected to detect the resulting malfunction.
BASIC SERVICE PROCEDUREKA24DE (EURO OBD)
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment
EC-3048

WORK SUPPORT MODENEEC0034S04
WORK ITEM CONDITION USAGE
TP SW/TP SEN IDLE POSI ADJ+FOLLOW THE BASIC INSPECTION IN THE SERVICE
MANUALWhen adjusting the idle throttle
position
IGNITION TIMING ADJ*+IGNITION TIMING FEEDBACK CONTROL WILL BE
HELD BY TOUCHING ªSTARTº. AFTER DOING SO,
ADJUST IGNITION TIMING WITH A TIMING LIGHT
BY TURNING THE CRANKSHAFT POSITION SEN-
SOR.When adjusting initial ignition tim-
ing
FUEL PRESSURE RELEASE+FUEL PUMP WILL STOP BY TOUCHING ªSTARTº
DURING IDLING.
CRANK A FEW TIMES AFTER ENGINE STALLS.When releasing fuel pressure
from fuel line
SELF-LEARNING CONT+THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL
COEFFICIENT.When releasing fuel pressure
from fuel line
TARGET IDLE RPM ADJ*+IDLE CONDITION When setting target idle speed
*: This function is not necessary in the usual service procedure.
SELF DIAGNOSTIC MODENEEC0034S05DTC and 1st Trip DTCNEEC0034S0501Regarding items of ªDTC and 1st trip DTCº, refer to
ªTROUBLE DIAGNOSIS Ð INDEXº, EC-3009.
Freeze Frame Data and 1st Trip Freeze Frame DataNEEC0034S0502
Freeze frame data
item*Description
DIAG TROUBLE
CODE
[PXXXX]+Engine Control component part/control system has a trouble code, it is displayed as ªPXXXXº. [Refer to
ªAlphabetical & P No. Index for DTCº (EC-3009).]
FUEL SYS-B1+ªFuel injection system statusº at the moment a malfunction is detected is displayed.
+One mode in the following is displayed.
ªMODE 2º: Open loop due to detected system malfunction
ªMODE 3º: Open loop due to driving conditions (power enrichment, deceleration enrichment)
ªMODE 4º: Closed loop - using oxygen sensor(s) as feedback for fuel control
ªMODE 5º: Open loop - has not yet satisfied condition to go to closed loop
CAL/LD VALUE [%]+The calculated load value at the moment a malfunction is detected is displayed.
COOLANT TEMP [ÉC]
or [ÉF]+The engine coolant temperature at the moment a malfunction is detected is displayed.
S-FUEL TRIM-B1 [%]+ªShort-term fuel trimº at the moment a malfunction is detected is displayed.
+The short-term fuel trim indicates dynamic or instantaneous feedback compensation to the base fuel
schedule.
L-FUEL TRIM-B1 [%]+ªLong-term fuel trimº at the moment a malfunction is detected is displayed.
+The long-term fuel trim indicates much more gradual feedback compensation to the base fuel schedule
than short-term fuel trim.
ENGINE SPEED
[rpm]+The engine speed at the moment a malfunction is detected is displayed.
VEHICLE SPEED
[km/h] or [mph]+The vehicle speed at the moment a malfunction is detected is displayed.
ABSOL TH-P/S [%]+The throttle valve opening angle at the moment a malfunction is detected is displayed.
B/FUEL SCHDL
[msec]+The base fuel schedule at the moment a malfunction is detected is displayed.
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
CONSULT-II
EC-3073

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
THRTL POS SEN [V]jj+The throttle position sensor signal volt-
age is displayed.
INT/A TEMP SE
[ÉC] or [ÉF]jj+The intake air temperature determined
by the signal voltage of the intake air
temperature sensor is indicated.
START SIGNAL
[ON/OFF]jj+Indicates [ON/OFF] condition from the
starter signal.+After starting the engine, [OFF] is dis-
played regardless of the starter sig-
nal.
CLSD THL POS
[ON/OFF]jj+Indicates idle position [ON/OFF] com-
puted by ECM according to the throttle
position sensor signal.
CLSD THL/P SW
[ON/OFF]j+Indicates mechanical contact [ON/OFF]
condition of the closed throttle position
switch.
AIR COND SIG
[ON/OFF]jj+Indicates [ON/OFF] condition of the air
conditioner switch as determined by
the air conditioning signal.
P/N POSI SW
[ON/OFF]jj+Indicates [ON/OFF] condition from the
PNP switch signal.
PW/ST SIGNAL
[ON/OFF]jj+Indicates [ON/OFF] condition of the
power steering oil pressure switch
determined by the power steering oil
pressure switch signal.
AMB TEMP SW
[ON/OFF]j+Indicates [ON/OFF] condition from the
ambient air temperature switch signal.
IGNITION SW
[ON/OFF]j+Indicates [ON/OFF] condition from igni-
tion switch.
INJ PULSE-B1 [msec]j+Indicates the actual fuel injection pulse
width compensated by ECM according
to the input signals.+When the engine is stopped, a cer-
tain computed value is indicated.
IGN TIMING [BTDC]j+Indicates the ignition timing computed
by ECM according to the input signals.
CAL/LD VALUE [%]+ªCalculated load valueº indicates the
value of the current airflow divided by
peak airflow.
ABSOL TH´P/S [%]+ªAbsolute throttle position sensorº indi-
cates the throttle opening computed by
ECM according to the signal voltage of
the throttle position sensor.
MASS AIRFLOW
[g´m/s]+Indicates the mass airflow computed by
ECM according to the signal voltage of
the mass air flow sensor.
IACV-AAC/V [%]j+Indicates the IACV-AAC valve control
value computed by ECM according to
the input signals.
PURG VOL C/V [%]+Indicates the EVAP canister purge vol-
ume control value computed by the
ECM according to the input signals.
+The opening becomes larger as the
value increases.
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION
KA24DE (EURO OBD)
CONSULT-II
EC-3075

12 RESET THROTTLE POSITION SENSOR IDLE POSITION MEMORY
With CONSULT-II
NOTE:
Always warm up engine to normal operating temperature. If engine is cool, the throttle position sensor idle posi-
tion memory will not be reset correctly.
1. Start engine.
2. Warm up engine to normal operating temperature.
3. Select ªCLSD THL POSº in ªDATA MONITORº mode manual trigger.
4. Stop engine. (Turn ignition switch OFF.)
5. Turn ignition switch ON and wait at least 5 seconds.
SEF864V
6. Turn ignition switch OFF and wait at least 5 seconds.
7. Repeat steps 5 and 6 until ªCLSD THL POSº in ªDATA MONITORº mode with CONSULT-II changes to ªONº.
SEF715Z
©GO TO 13.
13 CHECK TARGET IDLE SPEED
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªENG SPEEDº in ªDATA MONITORº mode.
3. Check idle speed.
700±50 rpm
OK or NG
OK©INSPECTION END
NG©Adjust idle speed. Refer to ªIdle Speed/Ignition Timing/Idle Mixture Ratio Adjustmentº,
EC-3035. Inspection end after adjust idle speed.
TROUBLE DIAGNOSIS Ð BASIC
INSPECTION
KA24DE (EURO OBD)
Basic Inspection
EC-3094

14 CHECK IGNITION TIMING
Without CONSULT-II
1. Warm up engine to normal operating temperature.
2. Stop engine and disconnect throttle position sensor harness connector.
SEF265S
3. Start engine.
4. Rev engine (2,000 to 3,000 rpm) two or three times under no-load and then run engine at idle speed.
5. Check ignition timing at idle using timing light.
SEF320V
Ignition timing:
15ɱ2É BTDC
OK or NG
OK©GO TO 15.
NG©1. Adjust ignition timing by turning distributor. Refer to ªIdle Speed/Ignition Timing/Idle
Mixture Ratio Adjustmentº, EC-3035.
2. GO TO 15.
15 CHECK BASE IDLE SPEED
Without CONSULT-II
Make sure that engine speed falls to the following speed.
650±50 rpm
OK or NG
OK©GO TO 16.
NG©1. Adjust base idle speed by turning idle speed adjusting screw. Refer to ªIdle Speed/
Ignition Timing/Idle Mixture Ratio Adjustmentº, EC-3035.
2. GO TO 16.
TROUBLE DIAGNOSIS Ð BASIC
INSPECTION
KA24DE (EURO OBD)
Basic Inspection
EC-3095