2002 NISSAN TERRANO Service Repair Manual

System Diagram
YEC235A
ENGINE AND EMISSION CONTROL OVERALL SYSTEMTD27Ti
EC-303

Vacuum Hose Drawing
q1Throttle body control valve actuator
to throttle body control solenoid
valve
q
2EGR valve to 3-way connector
q
3EGRC-solenoid valve A to 3-way
connector-1q
4EGRC-solenoid valve B to 3-way
connector-1
q
5Throttle body control solenoid
valve to 2-way connector-2
q
6EGRC-solenoid valve A to 3-way
connector-2q
7Tube to 3-way connector-2
q
8Tube to vacuum pump
q
9Tube to brake booster
Refer to ªSystem Diagramº, on previous page for vacuum control system
NEF759
ENGINE AND EMISSION CONTROL OVERALL SYSTEMTD27Ti
EC-304

System Chart
Crankshaft position sensor
(TDC)E
ECM
Control sleeve position sensorE
Fuel temperature sensorE
Mass air flow sensorE
Engine coolant temperature sen-
sorE
Needle lift sensorE
Accelerator position sensorE
Accelerator position switchE
Air conditioner switchE
Ignition switchE
Battery voltageE
Vehicle speed sensorE
Brake switchE
Atmospheric pressure sensor
(inside ECM)E
EFuel injection controlEElectric governor
EFuel injection timing controlEInjection timing control valve
EFuel cut controlEFuel cut solenoid valve
EGlow control systemEGlow relay & glow lamp
EOn board diagnostic systemEMalfunction indicator lamp
(On the instrument panel)
EEGR valve & Throttle control
valve controlEEGRC-solenoid valve A, B and
throttle control solenoid valve
(models for Germany)
EAir conditioning cut controlEAir conditioner relay
ENGINE AND EMISSION CONTROL OVERALL SYSTEMTD27Ti
EC-305

Fuel Injection System
SYSTEM DESCRIPTION
Three types of fuel injection control are provided to accommodate engine operating conditions; normal control,
idle control and start control. The ECM determines the appropriate fuel injection control. Under each control,
the amount of fuel injected is compensated to improve engine performance. The ECM performs duty cycle
control on the electric governor (built into the fuel injection pump) according to sensor signals to compensate
the amount of fuel injected to the preset value.
START CONTROL
Input/output signal line
Engine coolant temperature sensorEEngine coolant temperature
ECM
EElectric
governorCrankshaft position sensor (TDC)EEngine speed
Control sleeve position sensor
EControl sleeve position
When the ECM receives a start signal from the ignition switch, the
ECM adapts the fuel injection system for the start control. The
amount of fuel injected at engine starting is a preset program value
in the ECM. The program is determined by the engine speed and
engine coolant temperature.
For better startability under cool engine conditions, the lower the
coolant temperature becomes, the greater the amount of fuel
injected. The ECM ends the start control when the engine speed
reaches a value between 800 rpm and 1,200 rpm, which is deter-
mined by the engine coolant temperature and shifts the control to
the normal or idle control.
SEF648S
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONTD27Ti
EC-306

IDLE CONTROL
Input/output signal line
Engine coolant temperature sensorEEngine coolant temperature
ECM
EElectric
governor
Crankshaft position sensor (TDC)EEngine speed
Air conditioner switch
EAir Conditioner operation
Control sleeve position sensor
EControl sleeve position
Accelerator position switch
EIdle position
Vehicle speed sensor
EVehicle speed
When the ECM determines that the engine speed is at idle, the fuel injection system is adapted for the idle
control. The ECM regulates the amount of fuel injected corresponding to changes in load applied to the engine
to keep engine speed constant. The ECM also provides the system with a fast idle control in response to the
engine coolant temperature.
NORMAL CONTROL
Input/output signal line
Crankshaft position sensor (TDC)EEngine speed
ECM
EElectric
governor
Control sleeve position sensorEControl sleeve position
Accelerator position sensor
EAccelerator position
Vehicle speed sensor
EVehicle speed
The amount of fuel injected under normal driving conditions is
determined according to sensor signals. The crankshaft position
sensor (TDC) detects engine speed and the accelerator position
sensor detects accelerator position. These sensors send signals to
the ECM.
The fuel injection data, predetermined by correlation between vari-
ous engine speeds and accelerator positions, are stored in the
ECM memory, forming a map. The ECM determines the optimal
amount of fuel to be injected using the sensor signals in compari-
son with the map.
SEF649S
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONTD27Ti
Fuel Injection System (Cont'd)
EC-307

FUEL TEMPERATURE COMPENSATION
Input/output signal line
Fuel temperature sensorEFuel temperature
ECM
EElectric
governorCrankshaft position sensor (TDC)EEngine speed
Control sleeve position sensor
EControl sleeve position
The amount of fuel leaking at or around high-pressure parts inside the fuel injection pump varies with the fuel
temperature and engine speed. This will result in a difference between the target amount of fuel injected and
the actual amount. The ECM compensates for the actual amount depending on the signal obtained from the
fuel temperature sensor.
DECELERATION CONTROL
Input/output signal line
Accelerator position sensorEAccelerator position
ECM
EElectric
governor
Crankshaft position sensor (TDC)EEngine speed
The ECM cuts power supply delivery to the electric governor during deceleration for better fuel efficiency. The
ECM determines the time of deceleration according to signals from the accelerator position sensor and crank-
shaft position sensor (TDC).
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONTD27Ti
Fuel Injection System (Cont'd)
EC-308

Fuel Injection Timing System
SYSTEM DESCRIPTION
The fuel injection timing system determines the optimal fuel injection timing, based on engine speed, injection
quantity, engine coolant temperature and atmospheric pressure. The timing is formed by a basic value (Basic
Control) and two correction values. By performing a duty cycle signal on the timing control valve, the ECM
allows the valve to provide optimal injection timing. The ECM also performs feedback control on the timing
control valve using the signal from the needle lift sensor which detects the actual fuel injection timing.
BASIC CONTROL
Input/output signal line
Crankshaft position sensor (TDC)EEngine speed
ECM
E
Injection
timing con-
trol valve
Needle lift sensorEInjection timing
Control sleeve position sensor
EControl sleeve position
The optimal fuel injection timing data, predetermined in proportion
to engine speeds and amount of fuel injected, are stored in the
ECM memory. The ECM uses the data to control the fuel injection
timing.
HIGH ALTITUDE COMPENSATION
Input/output signal line
Crankshaft position sensorEEngine speed
ECM
E
Injection
timing
control
deviceControl sleeve position sensorEControl sleeve position
Atmospheric pressure sensor
EAtmospheric sensor
Needle lift sensor
EInjection timing
Fuel temperature sensor
EFuel temperatureEElectric
governor
For better drivability in high altitude areas, the fuel injection timing
is advanced and the fuel quantity is reduced according to the atmo-
spheric pressure.
SEF650S
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONTD27Ti
EC-309

ENGINE COOLANT TEMPERATURE COMPENSATION (When starting)
Input/output signal line
Crankshaft position sensor (TDC)EEngine speed
ECM
E
Injection
timing con-
trol valveEngine coolant temperature sensorEEngine coolant temperature
Needle lift sensor
EIgnition timing
Ignition switch
EStart signal
For better startability under cool engine conditions, the fuel injec-
tion timing is compensated according to the engine coolant tem-
perature.
ENGINE COOLANT TEMPERATURE COMPENSATION (During driving)
Input/output signal line
Crankshaft position sensor (TDC)EEngine speed
ECM
EInjection
timing con-
trol valveEngine coolant temperature sensorEEngine coolant temperature
Needle lift sensor
EInjection timing
For better exhaust efficiency under cool engine conditions, the fuel
injection timing is controlled within a compensation range depend-
ing on the engine speed, engine coolant temperature and amount
of fuel injected.
MEC023E
SEF652S
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONTD27Ti
Fuel Injection Timing System (Cont'd)
EC-310