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Nissan PULSAR N13 Series / ASTRA LD Series. Manual - part 25

Fuel and Engine Management

101

Location of the idle air control (IAC) valve. Inset shows

the terminal identification.

(b) Check for a binding throttle cable, throttle

shaft or throttle position sensor.

tance as described later in this section.

(d) Ensure that the battery terminals and the

engine earth terminals are clean and secure.

(e) Check the operation of the Park/Neutral

switch and the transaxle as described in the Automatic
Transaxle section under the Neutral Safety Switch
heading.

(f) Check the spark plug gaps as described in the

Engine Tune-up section.

(g) Check the base idle speed adjustment.

(h) Check the fuel pressure and check the system

for leaks as described previously.

(I) Check the alternator voltage output as de-

scribed in the Electrical System section to ensure that
it is between 9-17 volts.

(j) Remove the IAC valve and check the bore in

the throttle body for dirt or damage.

(7) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector.

(8) Disconnect the wiring connector from the

IAC valve.

(9) Check for voltage at each of the terminals on

the IAC valve wiring connector using a test lamp.

If the test lamp flashes at each terminal, correct

operation of the wiring and control unit is indicated.
check for faulty IAC valve terminals. If no fault is
found renew the IAC valve.

If the test lamp is a steady light at one or more

terminals, proceed to operation (10).

If the test lamp does not flash at one or more of

the terminals proceed as follows:

(a) Check the circuit with no voltage for shorts

and for continuity between the IAC valve and the
control unit. Repair or renew the wiring harness as
necessary.

(b) Measure the resistance across the IAC valve

terminals A and B, and across terminals C and D.

The resistance should be more than 30 ohms.

If the resistance is not as specified, renew the IAC

valve.

If the resistance is as specified, check for faulty

wiring connector terminals on the IAC valve and the
control unit. If no fault is found, renew the control
unit

(10) Switch the ignition Oft' and disconnect the

control unit wiring connectors.

(11) Switch the ignition On and check the IAC

connector with the test lamp again. If the light is stilt
steady on one or more terminals there is a short
circuit to voltage in the wiring harness. Repair or
renew as necessary.

(12) If the light is not on, check for faulty IAC

valve terminals. If no fault is found renew the IAC
valve.

To Remove and Install

(1) Disconnect the negative battery terminal.
(2) On 1.6 liter engines, remove the air cleaner

assembly as previously described.

(3) Disconnect the wiring connector from the

IAC valve.

(4) Remove the IAC valve retaining screws and

withdraw the IAC valve and O ring.

View of the IAC valve removed from the throttle body

assembly. 1.6 liter engine.

(5) Clean the IAC sealing surfaces to ensure

proper operation.

Installation is a reversal of the removal procedure

with attention to the following points:

(1) When installing a new IAC valve ensure that

the part number is correct as the valve is not
interchangeable between the 1.8 and 1.6 liter engines.

(2) Measure the length of the pintle extension as

shown in the illustration. If necessary push the pintle
in by exerting firm thumb pressure with a slight
rocking motion.

NOTE: Installing (he IAC valve with the
pintle protruding too far can damage the
valve.

\(V2

Fuel and Engine Management

View of the IAC valve removed from the engine.

Dimension A must not exceed 28 mm.

(3) Lubricate the IAC valve O ring with engine

oil and install the IAC valve. Tighten the retaining
screws securely.

(4). Install the IAC valve wiring connector and

the negative battery terminal.

(5) On 1.6 liter engines, install the air cleaner

assembly as previously described.

(6) Run the engine until normal operating tem-

perature and idle speed are attained.

NOTE: Several minutes may elapse before
the normal idle speed is attained.

(7) Hold the throttle open at approximately

3 000 rpm for 10 seconds to reset the IAC valve.

MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR

To Test - Codes 33 and 34

NOTE: The following test procedure
assumes that fault codes 33 or 34 have
been
displayed during the self diagnosis test
pro-
cedure. If no codes have been displayed
but
the operation of the MAP sensor is suspect,
begin the test procedure at operation (15).

(1) Erase the self diagnosis code memory as

previously described.

(2) Start and run the engine at idle speed for 60

seconds or until the ECM warning lamp lights.

(3) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If code 34 is displayed, remove the jumper lead

from the diagnostic link connector, erase the self
diagnosis codes and proceed to operation (7).

If code 33 is displayed, remove the jumper lead

from the diagnostic link connector, erase the self
diagnosis code memory and proceed to operation (4).

If no codes are displayed, but codes 33 or 34

were
displayed when the self diagnosis test procedure was
originally performed, an intermittent fault is indi-
cated. Proceed as follows:

(a) Check for faulty wiring connections. Check

that all wiring connectors are clean and secure.

(b) Check that all earth wires are secure.
(c) Check the vacuum hose to the MAP sensor

for deterioration or restriction.

(4) Disconnect the wiring connector from the

MAP sensor.

(5) Start and run the engine at idle speed for 60

seconds or until the ECM warning lamp lights.

(6) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If code 33 is displayed, measure the voltage at

the
MAP sensor wiring connector terminal B with a
voltmeter to earth. Renew the control unit if the
voltage is less than 1 volt.

If the voltage is more than 1 volt, check the

wiring
harness for a short to voltage between terminal B and
the control unit wiring connector terminal Cll.
Repair or renew the wiring harness as necessary.

If code 34 is displayed, proceed as follows:

(a) Check for a restricted or leaking MAP sensor

vacuum hose.

(b) Check the wiring harness for continuity and

shorts between terminals A on the MAP sensor
connector and terminal A11 on the control unit wiring
connector. Repair or renew the wiring harness as
necessary.

If no faults are indicated in the above two checks,

proceed to operation (15).

(7) Disconnect the wiring connector from the

MAP sensor and connect a jumper lead between
terminals B and C on the wiring connector.

(8) Start and run the engine at idle speed for 60

seconds or until the ECM warning lamp lights.

(9) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If code 33 is displayed, proceed to operation (15).
If code 34 is displayed, proceed as follows.

Location of the MAP sensor. Inset shows the terminal

identification.

Fuel and Engine Management

103

(10) Remove the jumper lead from the MAP

sensor wiring connector and measure the voltage
across terminals A and C on the MAP sensor wiring
connector.

If the voltage is below 4 volts, proceed to opera-

tion (12).

If the voltage is 4-6 volts, proceed as follows.

(11) With the ignition switched Off, disconnect

the wiring connectors from the control unit and check
the wiring harness for continuity and shorts between
MAP sensor wiring connector terminal B and control
unit wiring connector terminal C11. Check the wiring
connectors for faults. Repair or renew the wiring
harness as necessary.

If no fault is found, renew the control unit and

retest for fault codes.

(12) Disconnect the wiring connector from the

throttle position sensor.

(13) Measure the voltage across terminals A and

C on the MAP sensor wiring connector.
If the voltage is 4-6 volts, renew the throttle
position sensor as described later in this section.
If the voltage is below 4 volts, proceed as follows.

(14) With the ignition switched Off, disconnect

the wiring connectors from the control unit and check
the wiring harness for continuity and shorts between
the MAP sensor wiring connector terminal C and
control unit wiring connector terminal C14. Check the
wiring connectors. Repair or renew the wiring harness
as necessary.

If no fault is found, renew the control unit and

retest for fault codes.

(15) Test the MAP sensor as follows:

(a) With the ignition switched On and the MAP

sensor wiring connector connected, measure the volt-
age across terminals A and B by backprobing the
MAP sensor wiring connector. The voltage should be
as follows:

ALTITUDE VOLTAGE

Below 305 m ..........................................3.8-5.5 volts

305-610 m .............................................3.6-5.3 volts

610-914 m .............................................3.5-5.1 volts

914-1 219 m..........................................3.3-5.0 volts

1 219-1 524 m ......................................3.2-4.8 volts

1 524-1 829 m ......................................3.0-4.6 volts

1 829-2 133 m ......................................2.9-4.5 volts
2 133-2 438 m.......................................2.8-4.3 volts
2 438-2 743 m ......................................2.6-4.2 volts

2 743-3 048 m ......................................2.5-4.0 volts

If the voltage is not as specified, renew the MAP

sensor.

(b) If the voltage is as specified, apply a 34 kPa

vacuum to the MAP sensor using a vacuum pump.
The voltage should be 1.2-2.3 volts lower than that
measured in operation (a).

If the voltage is not as specified, renew the MAP

sensor.

If no fault is found, check the vacuum supply hose

for restriction, leakage or correct installation.

To Remove and Install

(1) Disconnect the negative battery terminal.
(2) Disconnect the MAP sensor wiring connec-

tor and the vacuum hose.

(3) Remove the retaining screws and remove the

MAP sensor from the vehicle.

Installation is a reversal of the removal procedure

with attention to the following points:

(1) If a new MAP sensor is to be installed ensure

that the colored insert inside the connector cavity
matches the color of the wiring connector.

(2) Ensure that the wiring connector and the

vacuum hose are connected securely.

THROTTLE CABLE
To Remove and Install

(1) On 1.6 liter engines, remove the air cleaner

assembly as previously described.

(2) Slide the outer throttle cable from the

mounting bracket, rotate the throttle linkage and
disconnect the inner throttle cable from the throttle
linkage.

(3) Disconnect the throttle cable from the retain-

ing clamps in the engine compartment.

(4) Disconnect the plastic retainer from the top

of the throttle pedal and disengage the inner throttle
cable from the pedal.

(5) Remove the bolts securing the throttle cable

to the bulkhead and withdraw the throttle cable.

Installation is a reversal of the removal procedure.

To Adjust

(1) On 1.6 liter engines, remove the air cleaner

assembly as previously described.

(2) Remove the snap ring securing the outer

throttle cable to the insulator in the mounting bracket.

View showing the throttle cable adjustment point. 1.8

liter engine.

104

Fuel and Engine Management

(3) Gently pull the outer throttle cable until the

inner cable remains taut without moving the throttle
linkage.

(4) Install the snap ring into the groove

posi-
tioned second from the insulator.

(5) Depress the throttle pedal and check that the

throttle valve opens fully and returns to the idle
position when the pedal is released.

(6) On 1.6 liter engines, install the air

cleaner
assembly.

7. ELECTRONIC COMPONENTS

NOTE: Before proceeding with any of the
operations in this section, refer to the Ser-
vice Precautions and Procedures heading.

TO CHECK IGNITION SYSTEM

(1) Perform the test procedure described in the

Roadside Trouble Shooting section. Repair or renew
components as necessary.

(2) Perform the self diagnosis test procedure as

previously described and rectify any faults. If there is
no spark, proceed as follows.

(3) Disconnect the 4 pin wiring connector from

the distributor and check for spark at a spark plug
high tension lead using the test spark plug.

If there is a spark, renew the pickup coil in the

distributor.

If there is no spark, proceed as follows.

(4) Connect the coil high tension lead to the test

spark plug and check for spark.

If there is a spark, check the distributor cap and

rotor for cracks and moisture. Repair or renew as
necessary.

If there is no spark, proceed as follows.

(5) Disconnect the 2 pin wiring connector from

the distributor.

(6) With the ignition switched On. measure the

voltage at terminals A and B on the distributor 2 pin
wiring connector.

If the voltage at terminal B only is under 10 volts,

check the wiring harness for continuity between
terminal B on the distributor 2 pin wiring connector
and terminal 2 on the black ignition coil wiring
connector. Repair or renew the wiring harness as
necessary. If no fault is found, renew the ignition coll.

If the voltages at both terminals is under 10 volts,

check the wiring harness between terminal A on the
distributor 2 pin wiring connector and terminal 1 on
the black ignition coil wiring connector for continuity.
Also check the fuel pump fuse and the wiring harness
between the ignition switch and the ignition coil.
Repair or renew the wiring harness as necessary.

If the voltage at both terminals is 10 volts or

more, proceed as follows.

(7) Connect the 2 pin wiring connector to the

distributor.

(8) With the ignition switched On, measure the

voltage at the tachometer signal wire.

Illustration identifying the 2 and 4 pin distributor wiring

connector terminals.

If the voltage is under 1 volt, check the tacho-

meter signal wire for continuity from the ignition coil.
Repair or renew the wiring harness as necessary.

If the voltage is 1-10 volts, renew the distributor

control module. If there is still no spark, renew the
ignition coil also.

If the voltage is over 10 volts, proceed as follows.

(9) With the ignition switch in the Start position,

check for voltage at the tachometer signal wire using
a test lamp.

If the test lamp flashes, replace the ignition coil

with a known serviceable unit. If there is still no
spark, install the original coil and renew the control
module.

If the test lamp remains illuminated, proceed as

follows.

(10) Remove the distributor cap and disconnect

the pickup coil wiring connector from the control
module.

(11) Connect a voltmeter between the tachometer

signal wire and earth.

(12) Connect the lead of a test lamp to a power

supply of 1.5-8 volts.

(13) With the ignition switched On, momentarily

connect the probe of the test lamp to terminal P on
the control module and note the voltage. The voltage
should decrease to 7-9 volts.

If there is no voltage decrease, check the control

module earth. If the earth is satisfactory, renew the
control module.

If the voltage decreases, proceed as follows.

(14) Check for spark at the coil high tension lead

as the test lamp is disconnected from terminal P on
the control module.

If there is no spark, proceed to operation (15).

If there is a spark, check that the steel rotor on the

distributor shaft is magnetized. If it is not renew the
distributor shaft assembly.

If the steel rotor is magnetized, check that the

resistance between the pickup coil leads is 500-1 500
ohms and not earthed. Renew the pickup coil as
necessary.

(15) Renew the ignition coil and check for spark.
If there is no spark check the coil high tension

lead. If no fault can be found, renew the control
module.

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