2001 NISSAN PICK-UP engine

Fuel Injection Control System
DESCRIPTION
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.
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 to the preset value.
Start control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection con-
trol (start control)Electronic control fuel injec-
tion pump Crankshaft position sensor (TDC) Engine speed
Ignition switch Start signal
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 control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection con-
trol (Idle control)Electronic control fuel injec-
tion pump Crankshaft position sensor (TDC) Engine speed
Park/Neutral position (PNP) switch Gear position
Battery Battery voltage
Accelerator position switch Idle position
Vehicle speed sensor Vehicle speed
Air conditioner switch Air conditioner signal
Intake air temperature sensor Intake air temperature
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 and heat up switch signal.
SEF648S
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTIONYD25DDTi
EC-3411

Normal control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Crankshaft position sensor (TDC) Engine speed
Fuel injection con-
trol (Normal con-
trol)Electronic control fuel injec-
tion pump Accelerator position sensor Accelerator position
Vehicle speed sensor Vehicle 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
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 control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection con-
trol (Maximum
amount control)Electronic control fuel injec-
tion pump 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 control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Accelerator position switch Accelerator positionFuel injection con-
trol (Deceleration
control)Electronic control fuel injec-
tion 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 to signals from the accelerator posi-
tion switch and crankshaft position sensor (TDC).
SEF649S
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTIONYD25DDTi
Fuel Injection Control System (Cont'd)
EC-3412

Fuel Injection Timing Control System
DESCRIPTION
The 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 perform feedback control for optimum injection timing in accordance with the map.
Air Conditioning Cut Control
DESCRIPTION
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Air conditioner switch Air conditioner ªONº signal
Air conditioner cut
controlAir conditioner relay Accelerator position sensor Accelerator position
Vehicle speed sensor Vehicle speed
Engine coolant temperature sensor Engine coolant temperature
System description
This system improves acceleration when the air conditioner is used.
When the accelerator pedal is fully depressed, the air conditioner is turned off for a few seconds.
When engine coolant temperature becomes excessively high, the air conditioner is turned off. This contin-
ues until the engine coolant temperature returns to normal.
Fuel Cut Control (at no load & high engine
speed)
DESCRIPTION
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Vehicle speed sensor Vehicle speed
Fuel cut controlElectronic control fuel injec-
tion pump Park/Neutral position (PNP) switch Neutral position
Accelerator position switch Accelerator position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (TDC) Engine speed
If the engine speed is above 2,700 rpm with no load (for example, in neutral and engine speed over 2,700
rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies based on engine speed.
Fuel cut will operate until the engine speed reaches 1,500 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under ªFuel Injection Control Systemº,
EC-3411.
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTIONYD25DDTi
EC-3413

Crankcase Ventilation System
DESCRIPTION
In this system, blow-by gas is sucked into the air inlet pipe after
oil separation by oil separator in the rocker cover.
INSPECTION
Ventilation hose
1. Check hoses and hose connections for leaks.
2. Disconnect all hoses and clean with compressed air. If any
hose cannot be freed of obstructions, replace.
SEC240D
SEC692
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTIONYD25DDTi
EC-3414

Installation
1. Referring to the figure and the marking which were made for
installation, connect the injection tubes to all the cylinders.
2. Connect temporarily the tubes to the cylinder head side only
by screwing 2 to 3 turns. Make sure that all tubes can be
connected to the pump side also.
3. Then, tighten the flare nuts of the cylinder head side and
pump side, starting from the opposite side from you.
4. Attach the injection tube clamp in the direction shown in the
figure.
5. Insert tightening bolt of the clamp (4-tube type) from the rear
to the front of the engine.
Injection Nozzle Oil Seal
Removal
Using a tool such as a flat-bladed screwdriver, pry the flange of
the seal, then remove it.
Installation
1. After the high-pressure injection nozzle assembly is installed,
push the seal from the cylinder head side until it contacts the
flange.
2. Make sure that the garter spring of the seal on the high-
pressure injection nozzle assembly side is not falling.
+Replace the oil seal with new one when the high-pres-
sure injection nozzle assembly is removed. (It is not nec-
essary to replace the oil seal when only injection tubes
are removed.)
JEF341Y
JEC335D
JEF343Y
BASIC SERVICE PROCEDUREYD25DDTi
Injection Tube and Injection Nozzle (Cont'd)
EC-3416

Spray Pattern Test
1. Check spray pattern by pumping tester handle one full stroke
per second.
NG spray pattern:
Does not inject straight and strong (B in the fig-
ure).
Fuel drips (C in the figure).
Does not inject evenly (D in the figure).
2. If the spray pattern is not correct, replace injection nozzle
assembly.
Electronic Control Fuel Injection Pump
REMOVAL AND INSTALLATION
Removal
1. Remove the parts shown below.
+Engine hood
+Engine coolant (drain)
+Engine cover
+Heater pipe under intake manifold
+Injection tubes
+Right splash cover (with undercover)
+Right front wheel
SEF434Z
JEC336D
BASIC SERVICE PROCEDUREYD25DDTi
Injection Tube and Injection Nozzle (Cont'd)
EC-3419

2. Disconnect the fuel hoses from the fuel injection pump.
3. Disconnect the harness connector from the fuel injection
pump.
+Disconnect the connector by pulling the connector stopper
fully.
+When the stopper is fully pulled, the connector will be dis-
connected together. For installation, push the connector half
way first, then press the stopper until it locks, so that the
connector is connected together.
4. Remove the fuel injection pump rear bracket.
5. Remove the front chain case.
+Move the power steering fluid reservoir tank from the bracket.
+Loosen and remove the mounting bolts in the reverse order
of the numbers shown in the figure.
+As for bolts 6, 10, and 11, remove with rubber washer
because there is not enough space for removing only the
bolts.
CAUTION:
To prevent foreign objects from getting in the engine, cover
the opening during the removal of the front chain case.
6. Adjust the No. 1 cylinder to the top dead center position.
+Turn the crankshaft pulley clockwise, then align the align-
ment mark (punched mark) of the camshaft sprocket to the
position shown in the figure.
+There is no indicator on the crankshaft pulley.
+It is not necessary to mark the secondary timing chain for
removal because it can be matched by the link color for
installation. However, the alignment mark on the fuel injec-
tion pump sprocket is difficult to see; mark it if necessary.
7. Remove the chain tensioner.
a. Push the plunger of the chain tensioner, then fix it with a tool
such as a push pin.
b. Using the hexagon wrench (face to face: 5 mm) (SST),
remove the mounting bolts, then remove the chain tensioner.
+A multi-purpose tool may also be used.
JEF351Y
JEF352Y
JEF353Y
JEF354Y
JEF355Y
BASIC SERVICE PROCEDUREYD25DDTi
Electronic Control Fuel Injection Pump
(Cont'd)
EC-3420

12. Using the hexagon wrench (face to face: 6 mm, long-type)
(SST), remove the mounting bolts of the fuel injection pump
sprocket.
+It is not necessary to remove the washer of the fuel injection
pump sprocket.
13. Using the sprocket holder (SST), hold the fuel injection pump
sprocket to prevent falling.
+When the sprocket holder is installed, if the positioning stop-
per pin interferes, pull out the stopper pin approximately 10
mm (0.39 in), then install it.
+After the sprocket holder is installed temporarily, insert the
extension bar (SST) and Torx socket in the three holes A.
After positioning the holes, tighten the holder mounting bolts.
(Refer to the step 14 about the tool.)
+The length of the sprocket holder mounting bolts should be
approximately 15 mm (0.59 in) (M6 thread length).
+Make sure that the a- and b-faces of the sprocket holder
contact the bottom side of the sprocket 15 mm (0.59 in)
(small diameter side).
CAUTION:
Do not remove the sprocket holder until the fuel injection
pump is installed.
+After the sprocket holder is installed, pull out the positioning
stopper pin (SST) from the fuel injection pump sprocket.
14. Using the extension bar [SST: whole length 43 mm (1.69 in)]
and the Torx socket (Q6-E12: commercially available),
remove the mounting bolts, them remove the fuel injection
pump toward the rear of the engine.
+Even after all the mounting bolts are removed, the fuel injec-
tion pump is still held by a dowel pin.
CAUTION:
Do not disassemble or adjust the fuel injection pump.
JEF360Y
JEF361Y
JEF362Y
JEF363Y
JEF364Y
BASIC SERVICE PROCEDUREYD25DDTi
Electronic Control Fuel Injection Pump
(Cont'd)
EC-3422