Page 1065 of 3189
Engine Control Component Parts LocationNJEC0607
NEF396A
GI
MA
EM
LC
FE
CL
MT
AT
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE AND EMISSION CONTROL OVERALL SYSTEMYD
Engine Control Component Parts Location
EC-11
Page 1066 of 3189
SEF894Y
ENGINE AND EMISSION CONTROL OVERALL SYSTEMYD
Engine Control Component Parts Location (Cont’d)
EC-12
Page 1067 of 3189
NEF376A
GI
MA
EM
LC
FE
CL
MT
AT
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE AND EMISSION CONTROL OVERALL SYSTEMYD
Engine Control Component Parts Location (Cont’d)
EC-13
Page 1068 of 3189
Circuit DiagramNJEC0608
YEC320A
ENGINE AND EMISSION CONTROL OVERALL SYSTEMYD
Circuit Diagram
EC-14
Page 1069 of 3189
System DiagramNJEC0609
YEC399A
GI
MA
EM
LC
FE
CL
MT
AT
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE AND EMISSION CONTROL OVERALL SYSTEMYD
System Diagram
EC-15
Page 1070 of 3189
System ChartNJEC0611
Input (Sensor) ECM Function Output (Actuator)
Electronic control fuel injection pump
Crankshaft position sensor (TDC)
Engine coolant temperature sensor
Accelerator position sensor
Accelerator position switch
Park/Neutral position (PNP) switch*
Ignition switch
Battery voltage
Vehicle speed sensor
Air conditioner switch
Mass air flow sensor
Stop lamp switchFuel injection controlElectronic control fuel injection
pump
Fuel injection timing controlElectronic control fuel injection
pump
Fuel cut controlElectronic control fuel injection
pump
Glow control system Glow relay & glow lamp
On board diagnostic system MI (On the instrument panel)
EGR volume control EGR volume control valve
Cooling fan control Cooling fan relay
Air conditioning cut control Air conditioner relay
*: If so equipped
ENGINE AND EMISSION CONTROL OVERALL SYSTEMYD
System Chart
EC-16
Page 1071 of 3189

Fuel Injection Control System
DESCRIPTIONNJEC0612System DescriptionNJEC0612S01Three 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.
Pulse signals are exchanged between ECM and electronic control fuel injection pump (control unit is built-in).
The fuel injection pump control unit performs duty control on the spill valve (built into the fuel injection pump)
according to the input signals to compensate the amount of fuel injected tothe preset value.
Start ControlNJEC0612S02Input/Output Signal ChartNJEC0612S0201
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection
control (start
control)Electronic control fuel
injection pump Crankshaft position sensor (TDC) Engine speed
Ignition switch Start signal
SEF648S
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 the specific value,
and shifts the control to the normal or idle control.
Idle ControlNJEC0612S03Input/Output Signal ChartNJEC0612S0301
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection
control (Idle con-
trol)Electronic control fuel
injection pump Crankshaft position sensor (TDC) Engine speed
Battery Battery voltage
Accelerator position switch Idle position
Vehicle speed sensor Vehicle speed
Air conditioner switch Air conditioner signal
When the ECM determines that the engine speed is at idle, the fuel injectionsystem 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 signal.
GI
MA
EM
LC
FE
CL
MT
AT
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONYD
Fuel Injection Control System
EC-17
Page 1072 of 3189

Normal ControlNJEC0612S04Input/Output Signal ChartNJEC0612S0401
Sensor Input Signal to ECM ECM Function Actuator
Crankshaft position sensor (TDC) Engine speedFuel injection
control (Normal
control)Electronic control fuel
injection pump
Accelerator position sensor Accelerator position
SEF649S
The amount of fuel injected under normal driving conditions is determinedaccording to sensor signals. The
crankshaft position sensor (TDC) detects engine speed and the accelerator position sensor detects accelera-
tor position. These sensors send signals to the ECM.
The fuel injection data, predetermined by correlation between various 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 comparison with the map.
Maximum Amount ControlNJEC0612S05Input/Output Signal ChartNJEC0612S0501
Sensor Input Signal to ECM ECM Function Actuator
Mass air flow sensor Amount of intake air
Fuel injection
control (Maxi-
mum amount
control)Electronic control fuel
injection pump Engine coolnat temperature sensor Engine coolant temperature
Crankshaft position sensor (TDC) Engine speed
Accelerator position sensor Accelerator position
The maximum injection amount is controlled to an optimum by the engine speed, intake air amount, engine
coolant temperature, and accelerator opening in accordance with the driving conditions.
This prevents the oversupply of the injection amount caused by decreased air density at a high altitude or
during a system failure.
Deceleration ControlNJEC0612S06Input/Output Signal ChartNJEC0612S0601
Sensor Input Signal to ECM ECM Function Actuator
Accelerator position switch Accelerator positionFuel injection
control (Decel-
eration control)Electronic control fuel
injection pump
Crankshaft position sensor (TDC) Engine speed
The ECM sends a fuel cut signal to the electronic control fuel injection pump during deceleration for better
fuel efficiency. The ECM determines the time of deceleration according tosignals from the accelerator posi-
tion switch and crankshaft position sensor (TDC).
Fuel Injection Timing Control System
DESCRIPTIONNJEC0613The target fuel injection timing in accordance with the engine speed and the fuel injection amount are recorded
as a map in the ECM beforehand. The ECM and the injection pump control unit exchange signals and per-
form feedback control for optimum injection timing in accordance with themap.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONYD
Fuel Injection Control System (Cont’d)
EC-18