1998 NISSAN PICK-UP Repair Manual

Distributor Ignition (DI) System
INPUT/OUTPUT SIGNAL LINE
Camshaft position sensorcEngine speed and piston position
ECM
(ECCS
control
module)
cPower
transistor
Mass air flow sensorcAmount of intake air
Engine coolant temperature sensor
cEngine coolant temperature
Throttle position sensor
c
Throttle position
Throttle valve idle position
Vehicle speed sensor
cVehicle speed
Ignition switch
cStart signal
Intake air temperature sensor
cIntake air temperature
Neutral position switch
cGear position
Battery
cBattery voltage
SYSTEM DESCRIPTION
The ignition timing is controlled by the ECM to maintain the best
air-fuel ratio for every running condition of the engine.
The ignition timing data is stored in the ECM. This data forms the
map shown left.
The ECM detects information such as the injection pulse width
and camshaft position sensor signal. Responding to this
information, ignition signals are transmitted to the power transis-
tor.
e.g. N: 1,800 rpm, Tp: 1.50 msec
A ÉBTDC
During the following conditions, the ignition timing is revised by
the ECM according to the other data stored in the ECM.
1 At starting
2 During warm-up
3 At idle
4 When swirl control valve operates
5 Hot-engine operation
6 At acceleration
SEF742M
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONKA
EC-17

Air Conditioning Cut Control
INPUT/OUTPUT SIGNAL LINE
Air conditioner switchcAir conditioner ``ON'' signal
ECM
(ECCS
control
module)
cAir condi-
tioner
relayThrottle position sensorcThrottle valve opening angle
Ignition switch
cStart signal
Engine coolant temperature sensor
cEngine coolant temperature
SYSTEM DESCRIPTION
This system improves engine operation when the
air conditioner is used.
Under the following conditions, the air conditioner
is turned off.
lWhen the accelerator pedal is fully depressed
lWhen cranking the engine
lWhen the engine coolant temperature becomes
excessively high
Fuel Cut Control (at no load & high engine
speed)
INPUT/OUTPUT SIGNAL LINE
Vehicle speed sensorcVehicle speed
ECM
(ECCS
control
module)
cInjectors
Neutral position switchcNeutral position
Throttle position sensor
cThrottle position
Engine coolant temperature sensor
cEngine coolant temperature
Camshaft position sensor
cEngine speed
If the engine speed is above 3,500 rpm with no load (for
example, in neutral and engine speed over 3,500 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 than deceleration control listed
under multiport fuel injection on EC-14.
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTIONKA
EC-18

Description
The evaporative emission system is used to reduce hydrocar-
bons emitted into the atmosphere from the fuel system. This
reduction of hydrocarbons is accomplished by activated char-
coals in the EVAP canister.
The fuel vapor from sealed fuel tank is led into the EVAP canis-
ter when the engine is off. The fuel vapor is then stored in the
EVAP canister. The EVAP canister retains the fuel vapor until the
EVAP canister is purged by air.
When the engine is running, the air is drawn through the bottom
of the EVAP canister. The fuel vapor will then be led to the intake
manifold.
When the engine runs at idle, the EVAP canister purge control
valve is closed. Only a small amount of vapor flows into the
intake manifold through the constant purge orifice.
As the engine speed increases and the throttle vacuum rises, the
EVAP canister purge control valve opens. The vapor is sucked
through both main purge and constant purge orifices.
Inspection
EVAP CANISTER
Check EVAP canister as follows:
1. Blow air in port
VAand check that there is no leakage.
2. Apply vacuum to port
VA. [Approximately þ13.3 to þ20.0 kPa
(þ133 to þ200 mbar, þ100 to þ150 mmHg, þ3.94 to þ5.91
inHg)]
3. Cover port
VDby hand.
4. Blow air in port
VCand check that it flows freely out of port
VB.
SEF044U
SEF312N
EVAPORATIVE EMISSION SYSTEMKA
EC-19

FUEL CHECK VALVE
1. Blow air through connector on fuel tank side.
A considerable resistance should be felt and a portion of air
flow should be directed toward the EVAP canister side.
2. Blow air through connector on EVAP canister side.
Air flow should be smoothly directed toward fuel tank side.
3. If fuel check valve is suspected of not properly functioning in
steps 1 and 2 above, replace it.
Rollover valve operation (RHD models only)
Ensure that continuity of air passage does not exist when the
installed rollover valve is tilted to 90É or 180É.
FUEL TANK VACUUM RELIEF VALVE
1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
Pressure:
15.3 - 20.0 kPa (0.1530 - 0.2001 bar, 0.156 - 0.204
kg/cm
2, 2.22 - 2.90 psi)
Vacuum:
þ6.0 to þ3.3 kPa (þ0.0598 to þ0.0333 bar, þ0.061 to
þ0.034 kg/cm
2, þ0.87 to þ0.48 psi)
3. If out of specification, replace fuel filler cap as an assembly.
CAUTION:
Use only a genuine fuel filler cap as a replacement.
EVAP CANISTER PURGE CONTROL SOLENOID
VALVE
Refer to EC-140.
SEF172U
SEF045U
SEF427N
SEF943S
EVAPORATIVE EMISSION SYSTEMKA
Inspection (Cont'd)
EC-20

Description
This system returns blow-by gas to the intake manifold collector.
The positive crankcase ventilation (PCV) valve is provided to
conduct crankcase blow-by gas to the intake manifold.
During partial throttle operation of the engine, the intake mani-
fold sucks the blow-by gas through the PCV valve.
Normally, the capacity of the valve is sufficient to handle any
blow-by and a small amount of ventilating air.
The ventilating air is then drawn from the air duct into the crank-
case. In this process the air passes through the hose connect-
ing air inlet tubes to the rocker cover.
Under full-throttle condition, the manifold vacuum is insufficient
to draw the blow-by flow through the valve. The flow goes
through the hose connection in the reverse direction.
On vehicles with an excessively high blow-by, the valve does not
meet the requirement. This is because some of the flow will go
through the hose connection to the intake collector under all
conditions.
Inspection
PCV (Positive Crankcase Ventilation) VALVE
With engine running at idle, remove PCV valve from breather
separator. A properly working valve makes a hissing noise as air
passes through it. A strong vacuum should be felt immediately
when a finger is placed over the valve inlet.
PCV 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.
SEF156E
SEF559A
SEC137A
ET277
POSITIVE CRANKCASE VENTILATIONKA
EC-21

Fuel Pressure Release
Before disconnecting fuel line, release fuel pressure from
fuel line to eliminate danger.
1. Start engine.
2. Perform ``FUEL PRESSURE RELEASE'' in ``WORK
SUPPORT'' mode with CONSULT.
(Touch ``START'' and after engine stalls, crank it two or
three times to release all fuel pressure.)
3. Turn ignition switch off.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Remove fuse for fuel pump.
2. Start engine.
3. After engine stalls, crank it two or three times to release
all fuel pressure.
4. Turn ignition switch off and reconnect fuel pump fuse.
Fuel Pressure Check
lWhen reconnecting fuel line, always use new clamps.
lMake sure that clamp screw does not contact adjacent
parts.
lUse a torque driver to tighten clamps.
lUse Pressure Gauge to check fuel pressure.
1. Release fuel pressure to zero, refer to above.
2. Disconnect fuel hose between fuel filter and fuel tube (engine
side).
3. Install pressure gauge between fuel filter and fuel tube.
4. Start engine and check for fuel leakage.
5. Read the indication of fuel pressure gauge.
At idling:
Approximately 235 kPa (2.35 bar, 2.4 kg/cm
2,34
psi)
A few seconds after ignition switch is turned OFF to
ON:
Approximately 294 kPa (2.94 bar, 3.0 kg/cm
2,43
psi)
6. Stop engine and disconnect fuel pressure regulator vacuum
hose from intake manifold.
7. Plug intake manifold with a rubber cap.
8. Connect variable vacuum source to fuel pressure regulator.
9. 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.
SEF823K
SEF046U
SEF047U
SEF718BA
BASIC SERVICE PROCEDUREKA
EC-22

Injector Removal and Installation
1. Release fuel pressure to zero.
2. Remove injector tube assembly with injectors from intake
manifold.
3. Remove injectors from injector tube assembly.
lDo 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 7.8 to 10.8 N´m (0.8 to 1.1 kg-m, 5.8
to 8.0 ft-lb).
b. Then, tighten all bolts to 16 to 21 N´m (1.6 to 2.1 kg-m, 12 to
15 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.
SEF048U
SEF049U
SEF050U
BASIC SERVICE PROCEDUREKA
EC-23

Fast Idle Cam (FIC) Inspection and
Adjustment
1. Remove air cleaner assembly.
2. Make sure the FIC alignment mark is centered on the lever
roller as shown in the figure.
lAn alignment mark is stamped on the FIC so that the top of
the cam will face in the correct direction.
lIf necessary, adjust the FIC screwVAuntil the alignment
mark is centered on the lever roller.
3. Start engine and warm up to operating temperature.
4. Measure clearance
VGbetween the lever roller and the top
of the FIC using a feeler gauge as shown in the figure.
Clearance
VG:
2.0 - 2.6 mm (0.079 - 0.102 in)
lIf clearanceVGis out of specification, adjust clearanceVG
using adjusting screwVBto 2.3 mm (0.091 in).
AEC147A
SEF553K
SEF554KA
SEF555KA
BASIC SERVICE PROCEDUREKA
EC-24