Nissan PULSAR N13 Series / ASTRA LD Series. Manual - part 21

Fuel and Engine Management

 

85

 

  

View of the 1.6 liter engine showing the engine management components. 

Air cleaner removed for clarity. 

series of tests on various components in the system 
and records the results, If a fault is discovered, the 
ECM warning lamp on the instrument cluster will 
illuminate while the engine is running. When the self 
diagnosis mode is activated, the ECM warning lamp 
will flash codes indicating the area in which the fault 
has occurred.

 

This function is very useful in locating system 

faults, particularly intermittent problems. However, 
the self diagnosis mode does not provide comprehen- 
sive testing of the EFI system, and therefore should 
always be used in conjunction with the other test 
procedures described later in this section in order to 
accurately locate system faults.

 

The high energy electronic ignition system con- 

sists of a distributor and an ignition coil.

 

The distributor has two functions. The first is to 

produce and distribute secondary high tension voltage 
to the spark plugs.

 

The second function is to provide the control unit 

with information on engine speed and crankshaft 
position.

 

The ignition timing is constantly adjusted by the 

control unit to suit varying engine and vehicle oper- 
ating conditions.

 

In the fuel injection system, a metered amount of 

fuel  is sprayed  into the air stream.  The air/fuel

 

mixture then enters the combustion chamber via the 
inlet valves.

 

On 1.6 liter engines, the fuel is injected by a single 

injector, located above the throttle valve within the 
throttle body assembly. The injector fires twice per 
engine revolution under most operating conditions.

 

On 1.8 liter engines, four injectors are used. The 

fuel is distributed to the injectors via the fuel rail. All 
injectors fire simultaneously once per engine revolu- 
tion under most operating conditions.

 

Under conditions of high load the control unit 

may signal the injector(s) to fire more often. However, 
if the engine speed exceeds 6 700 rpm the control unit 
will cease firing the injectors until the engine speed is 
below 6 200 rpm.

 

Fuel is supplied under pressure by an electric fuel 

pump mounted in the fuel tank and the pressure is 
regulated by a pressure regulator.

 

On 1.6 liter engines, the regulator consists of a 

spring tensioned diaphragm which is mounted to the 
side of the throttle body assembly. The fuel pressure is 
regulated by the tension of the spring against the 
diaphragm, opening and closing the fuel return port.

 

On 1.8 liter engines, the pressure regulator is 

mounted adjacent to the fuel rail and consists of a 
diaphragm with fuel pressure acting on one side and 
spring tension and manifold vacuum acting on the

 

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Fuel and Engine Management

 

 

other. The fuel pressure is maintained at a constant 
pressure relevant to the manifold vacuum. A dispos- 
able paper element fuel filter is mounted on the engine 
bulkhead.

 

The amount of fuel injected is relevant to the time 

the injector remains open. The basic time the injector 
remains open is governed by the control unit which 
uses information from the various sensors to give 
optimum engine efficiency for given conditions.

 

The idle air control (IAC) valve controls the fast 

idle speed during engine warm up and maintains the 
basic idle speed at a set value by compensating for 
loads such as air conditioning or the selection of Drive 
on automatic transaxle models.

 

The throttle body assembly is mounted to the 

inlet manifold and controls the amount of air entering 
the engine by the action of the throttle valve.

 

Efficient operation of the EFI system depends on 

accurate signals being received by the control unit and 
controlled air flow beyond the throttle valve. There- 
fore it is essential that all air, fuel and electrical 
connections be clean and tight.

 

3.    SERVICE PRECAUTIONS AND 

PROCEDURES

 

Electronic ignition systems can produce danger- 

ously high voltages in both the primary and secondary 
circuits. For this reason, extreme care must be taken 
when working on or near the ignition system.

 

Do not start the engine if the battery terminals are 

not clean and tight.

 

Do not use the fast charge or boost settings on a 

battery charger to start the engine.

 

Do not disconnect the battery terminals while the 

engine is running.

 

Disconnect the battery terminals before charging 

the battery.

 

Disconnect the negative battery terminal before 

working on the engine management system.

 

Do not subject the control unit to temperatures 

above 80 deg C.

 

Ensure that all wiring connectors are clean and 

tight.

 

Disconnect the battery terminals and the control 

unit wiring connectors before attempting any welding 
operations.

 

Do not direct a steam cleaning or pressure 

washing nozzle at engine management components 
when cleaning the engine.

 

Ensure that the ignition is Off prior to disconnect- 

ing the battery terminals, fusible links or the control 
unit wiring connectors.

 

TO CONNECT ELECTRICAL TEST 
EQUIPMENT

 

NOTE: Some types of tachometers, timing

 

lights and ignition system analysers are not 
compatible with this engine management 
system and may result in incorrect readings. 
It is therefore recommended that the man- 
ufacturer of the lest equipment be consulted 
before proceeding to use the equipment.

 

If a test procedure requires the use of a 

test lamp or voltmeter, ensure that only the 
specified instrument is used to prevent mis- 
leading diagnosis.

 

MULTIMETER

 

It is essential that in all tests where voltage or 

resistance is to be measured, a digital display multi- 
meter with a minimum 10 megohms impedance be 
used.

 

 

The correct method of backprobing the wiring connec- 

tors. The meter test probe should be modified with a 

piece of thin wire as shown. 

All meter readings are to be performed with the 

component wiring connectors installed unless other- 
wise instructed. This can be done by inserting the 
meter test probes from the wiring harness side of the 
connector or backprobing. If the test probes are not 
thin, they should be modified by attaching a thin piece 
of wire to the end, giving a fine point that will not 
damage the connector. Ensure that the wire is making 
good contact with the probe.

 

If sealing plugs or boots are removed from wiring 

connectors to facilitate backprobing, ensure that they 
are correctly installed at the conclusion of the test 
procedure.

 

To identify wiring connector terminals refer to the 

wiring circuit diagrams.

 

Test Lamp

 

To avoid damage to the electronic components 

when testing, the use of an LED (light emitting diode) 
test lamp is recommended.

 

Fuel and Engine Management

 

87

 

 

Fuel system wiring diagram for the 1.6 liter engine. 

88

 

Fuel and Engine Management

 

  

Fuel system wiring diagram for the 1.8 liter engine. 

BR   K