1998 NISSAN PICK-UP Repair Manual

Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment
PREPARATION
lMake sure that the following parts are in
good order.
(1) Battery
(2) Ignition system
(3) Engine oil and coolant levels
(4) Fuses
(5) ECM harness connector
(6) Vacuum hoses
(7) Air intake system
(Oil filler cap, oil level gauge, etc.)
(8) Fuel pressure(9) Engine compression
(10) Throttle valvelOn air conditioner equipped models,
checks should be carried out while the air
conditioner is ``OFF''.
lWhen measuring ``CO'' percentage, insert
probe more than 40 cm (15.7 in) into tail
pipe.
lTurn off headlamps, heater blower, rear
window defogger.
lKeep front wheels pointed straight ahead.
LHD MODELS
Overall inspection sequence
INSPECTION START
Perform diagnostic test mode II (Self-diagnostic results).
OK
cNG
Repair or replace.
.
Check & adjust ignition timing.
OKm
NG
Check & adjust idle
speed.
.
OKb
Check function of heated
oxygen sensor.
OK
cNG
Check harnesses of
heated oxygen sensor.
NG
cOK
Check CO%.
OK
.
cNG
Check emission control
parts and repair or
replace if necessary.
bRepair or replace har-
ness(es).
lReplace heated oxy-
gen sensor.
lCheck function of
heated oxygen sensor.
cNG
INSPECTION END
bOK
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
EC-25

START
Visually check the following:lAir cleaner clogginglHoses and ducts for leakslElectrical connectorslGasketlThrottle valve and throttle position sensor operations
Start engine and warm it up until engine coolant temperature
indicator points to the middle of gauge and ensure that engine
speed is below 1,000 rpm.
Open engine hood and run engine at about 2,000 rpm for about
2 minutes under no-load.
Perform the diagnostic test mode II (Self-diagnostic results).
OKNG
Repair or replace components as necessary.
.
Run engine at about 2,000 rpm for about 2 minutes under no-
load.
Rev engine two or three times under no-load, then run engine for
about 1 minute at idle speed.
1. Select ``IGNITION TIMING ADJ'' in WORK SUPPORT
mode.
2. Touch ``START''.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Stop engine and disconnect throttle position sensor
harness connector.
2. Start engine.
Rev engine (2,000 - 3,000 rpm) 2 or 3 times under no-load and
run engine at idle speed.
Check ignition timing with a timing light.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
10É 2É BTDC
OK NG
VAVB
SEF146U
SEF247F
SEF051PA
SEF248F
SEF546N
.
.
.
.
.
.
.
.
.
..
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-26

VAVB
b
Adjust ignition timing to the specified value by turning dis-
tributor after loosening bolts which secure distributor.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
10É 2É BTDC
VF
1. Select ``IGNITION TIMING ADJ'' in WORK
SUPPORT mode.
2. Touch ``START''.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Stop engine and disconnect throttle position
sensor harness connector.
2. Start engine.
.
Check base idle speed.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Read idle speed in ``IGN TIMING ADJ'' mode with
CONSULT.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Check idle speed.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
750 25 rpm
OKNG
Rev engine (2,000 - 3,000 rpm) 2 or 3 times under no
load and run engine at idle speed.
Adjust base idle speed by turning idle speed adjusting
screw.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
750 25 rpm
c
Touch ``Back''.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Stop engine and connect throttle position sen-
sor harness connector.
2. Start engine.
Rev engine (2,000 - 3,000 rpm) 2 or 3 times under no
load and run engine at idle speed.
VC
SMA189AA
SEF546N
SEF147U
SEF913J
SEF602K
.
.
.
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-27

VC
Check target idle speed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Read idle speed in ``DATA MONITOR''
mode with CONSULT.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------OR -----------------------------------------------------------------------------------------------------------------------------------------------------------------
Check idle speed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
800 50 rpm
OKNG
Check IACV-AAC valve and replace if necessary.
Check IACV-AAC valve harness and repair if nec-
essary.
Check ECM function* by substituting another
known good ECM.
* ECM may be the
cause of a problem,
but this is rarely the
case.
.
Set the diagnostic test mode II (heated oxygen
sensor monitor).
Run engine at about 2,000 rpm for about 2 minutes
under no-load.
Check heated oxygen sensor signal.
1. See ``M/R F/C MNT'' in ``DATA MONI-
TOR'' mode.
2. Maintaining engine at 2,000 rpm under
no-load (engine is warmed up
sufficiently), check that the monitor fluc-
tuates between ``LEAN'' and ``RICH''
more than 5 times during 10 seconds.
1 cycle: RICH®LEAN®RICH
2 cycles: RICH®LEAN®RICH®
LEAN®RICH
-----------------------------------------------------------------------------------------------------------------------------------------------------------------OR -----------------------------------------------------------------------------------------------------------------------------------------------------------------
Make sure that malfunction indicator lamp
goes on and off more than 5 times during
10 seconds at 2,000 rpm.
OK
cNG
VD
INSPECTION END
SEF051U
SEF909P
SEF052U
SEF051P
.
.
.
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-28

VD
Check heated oxygen sensor harness:
1. Turn off engine and disconnect battery ground
cable.
2. Disconnect ECM harness connector from ECM.
3. Disconnect heated oxygen sensor harness con-
nector and connect terminal for heated oxygen
sensor to ground with a jumper wire.
4. Check for continuity between terminal
V19of
ECM harness connector and ground metal on
vehicle body.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Continuity exists ... OK
Continuity does not exist ... NG
OK NG
Repair harness.
cVF
Connect ECM harness connector to ECM.
1. Select ``ENG COOLANT TEMP'' in
``ACTIVE TEST'' mode.
2. Set ``COOLANT TEMP'' at 20ÉC (68ÉF).
--------------------------------------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------------------------------------
lDisconnect engine coolant temperature
sensor harness connector.
lConnect a resistor (2.5 kW) between ter-
minals of engine coolant temperature sen-
sor harness connector.
Start engine and warm it up until engine coolant
temperature indicator points to the middle of gauge.
(Be careful to start engine after setting ``COOLANT
TEMP'' or installing a 2.5 kWresistor.)
Rev engine two or three times under no-load then
run engine at idle speed.
VE
MEF031DB
SEF053U
.
.
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-29

VE
Check ``CO''%.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Idle CO: 1.0 - 2.0% with engine runs smoothly.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
After checking ``CO''%
1. Touch ``BACK''.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Disconnect the resistor from terminals of engine
coolant temperature sensor harness connector.
2. Connect engine coolant temperature sensor harness
connector to engine coolant temperature sensor.
NG OK
Replace heated oxygen sensor, set the diagnostic test mode II
(heated oxygen sensor monitor) and make sure that malfunction
indicator lamp goes on and off more than 5 times during 10 sec-
onds. (2,000 rpm, no-load)
NGOK
.
Connect heated oxygen sensor harness connector to heated
oxygen sensor.VF
Check fuel pressure regulator. Refer to EC-22.
Check mass air flow sensor and its circuit. Refer to EC-89.
Check injector and its circuit. Refer to EC-144.
Clean or replace if necessary.
Check engine coolant temperature sensor and its circuit. Refer
to EC-95.
Check ECM function* by substituting another known good
ECM.
*: ECM may be the cause of a problem, but
this is rarely the case.
VB
.
.
..
.
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-30

RHD MODELS
Overall inspection sequence
INSPECTION START
Perform diagnostic test mode II (Self-diagnostic results).
OK
cNG
Repair or replace.
.
Check & adjust ignition timing.
OKm
NG
Check & adjust idle
speed.
OK
b
Check CO%.
OK
cNG
Check emission control
parts and repair or
replace if necessary.
INSPECTION END
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-31

Checking and adjusting idle speed, ignition timing
START
Visually check the following:
lAir cleaner clogging
lHoses and ducts for leaks
lElectrical connectors
lGasket
lThrottle valve and throttle position sensor operations
Start engine and warm it up until engine coolant temperature indi-
cator points to the middle of gauge and ensure that engine speed
is below 1,000 rpm.
Open engine hood and run engine at about 2,000 rpm for about 2
minutes under no-load.
Perform the diagnostic test mode II (Self-diagnostic results).
OKNG
Repair or replace components as neces-
sary.
.
Run engine at about 2,000 rpm for about 2 minutes under no-load.
Rev engine two or three times under no-load, then run engine for
about 1 minute at idle speed.
bVD
1. Select ``IGNITION TIMING ADJ'' in WORK SUPPORT
mode.
2. Touch ``START''.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Stop engine and disconnect throttle position sensor har-
ness connector.
2. Start engine.
Rev engine (2,000 - 3,000 rpm) 2 or 3 times under no-load and run
engine at idle speed.
Check ignition timing with a timing light.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
10É 2É BTDC
OK NG
VAVB
SEF146U
SEF247F
SEF051PA
SEF248F
SEF546N
.
.
.
.
.
.
.
.
.
..
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-32