Nissan PULSAR N13 Series / ASTRA LD Series. Manual - part 29

117

 

EMISSION CONTROL

 

INTRODUCTION 

To reduce the output level of the three primary 

automotive emissions, carbon monoxide (CO), hydro- 
carbons (HC) and oxides of nitrogen (NOx), and thus 
comply with legislation on the maintenance of clean 
air, several different emission control systems are used 
in the Pulsar range of vehicles covered by this manual.

 

The systems will be discussed under the headings 

(1) Crankcase Ventilation System, (2) Evaporative 
Control System, (3) Air Preheat System — 1.6 Liter 
Engine and (4) Exhaust Control System.

 

1.    CRANKCASE VENTILATION SYSTEM 

DESCRIPTION 

The crankcase ventilation system is of the closed 

type and is designed to prevent crankcase vapors 
being emitted into the atmosphere. Crankcase 
vapors are caused by gases escaping past the piston 
rings into the crankcase during the combustion pro- 
cess.

 

The crankcase vapors are collected in the cam- 

shaft housing from the crankcase via the various oil 
drain passages and the pipe from the side of the 
crankcase.

 

 

The crankcase vapors are then drawn into the 

engine via a branched hose connected to the camshaft 
housing oil baffle and the throttle body (1.8 liter 
engines) or inlet manifold (1.6 liter engines).

 

At idle speed, vapors are drawn through the 

small branch of the hose and into the engine.

 

As the engine speed increases, vapors are also 

drawn into the engine via the main hose.

 

TO SERVICE THE SYSTEM

 

(1)  At intervals of 40 000 km, disconnect the 

small engine ventilation hose from the throttle body 
or inlet manifold and check that the metering orifice 
is not blocked.

 

If necessary, clean the orifice using compressed air 

and solvent.

 

(2)  Disconnect all the engine ventilation hoses 

and check for blocking, collapsing and deterioration. 
Renew the hoses as necessary.

 

2.    EVAPORATIVE CONTROL SYSTEM 

Special Equipment Required: 

To Test Purge Valve — Hand vacuum pump 

DESCRIPTION 

The evaporative control system reduces the 

amount of hydrocarbons emitted to the atmosphere 
through fuel evaporation.

 

The vehicles covered by this manual use an 

absorption regeneration system to reduce vapor loss. 
The system utilizes a canister of activated charcoal to 
trap and hold the fuel vapors until they can be fed 
into the induction system for burning in the combus- 
tion chambers.

 

The basic components of the evaporative control 

system are a fuel tank with a sealed filler cap, a 
charcoal canister with a purge control valve, a fuel 
check valve and pipes and hoses to connect the 
various components.

 

NOTE: The fuel tank filler cap is not vented 
to the atmosphere but is equipped with a one 
way relief valve to prevent a vacuum form- 
ing in the fuel tank.

 

View of the engine ventilation hoses and pipe. 1.8 liter

engine. 

118

 

Emission Control

 

 

 

Installed view of the charcoal canister. 

When the engine is at rest, fuel vapor through 

evaporation gradually fills the air space in the fuel 
tank. The sealed filler cap prevents the escape of this 
vapor and pressure builds up within the system, 
forcing the vapor to flow into the charcoal canister 
which is located in the engine compartment beneath 
the windscreen wiper motor.

 

The fuel check valve prevents liquid fuel entering 

the charcoal canister when the fuel tank is full or the 
vehicle is parked on a steep incline. When the engine 
is running, the vapor is drawn via a hose from the 
charcoal canister to the throttle body and burnt in the 
combustion chambers.

 

TO RENEW CHARCOAL CANISTER

 

(1)  Suitably mark and disconnect the hoses from 

the canister. 

(2)  Release the retaining spring and remove the 

canister from the engine compartment. 

Installation is a reversal of the removal procedure.

 

TO RENEW FUEL CHECK VALVE

 

(1)   Disconnect the negative battery terminal.

 

 

(2)  Raise the rear of the vehicle and support it 

on chassis stands. Remove the left hand rear wheel. 

(3)  Drain the fuel from the fuel tank using a 

hand pump or a suitable siphon. Do not siphon fuel 
using the mouth. 

(4)  Remove the hoses from the check valve. 
(5)  Squeeze the retaining clip and remove the 

check valve from the mounting bracket. 

Installation is a reversal of the removal procedure.

 

TO SERVICE THE SYSTEM

 

(1)  Inspect the vacuum lines and connectors for 

signs of leakage, cracks and deterioration and renew 
as necessary. 

(2)  Remove the fuel tank cap and check that a 

slight resistance is felt, when vacuum is applied to the 
one-way relief valve in the centre of the cap. 

Renew the fuel tank cap if no resistance is felt or 

if the valve is blocked.

 

(3)  Inspect the fuel tank cap seal for deteriora- 

tion. Renew as necessary.

 

Installed view of the fuel check valve as seen with the

left hand rear wheel removed. 

Check the fuel filler cap seal for damage. 

23Q/LDZ GAUGE

 

Line drawing showing a hand vacuum pump.

Emission Control

 

119

 

 

(4)  Remove the charcoal canister as previously 

described under the heading To Renew Charcoal 
Canister. 

(5)  Shake the canister, there should no audible 

carbon movement. If there is, renew the canister. 

(6)  Check the purge valve by applying 20-35 

kPa of vacuum with a hand pump to the control port. 

Using a piece of hose, blow through the purge 

hose connection. If this is not possible, renew the 
canister.

 

Remove the vacuum source and blow air through 

the purge hose connection. If this is possible, renew 
the canister.

 

(7)  Apply 20-35 kPa air pressure into the fuel 

tank connector. Air should flow freely from all the 
other connectors.

 

If poor air flow through the drain tube exists, 

block off the fuel tank tube and blow compressed air 
at approximately 300 kPa through the purge port. 
Check the air flow and if still poor, renew the canister.

 

(8)  Apply 20-35 kPa air pressure to any one of 

the canister ports except the purge valve control port 
and with the other ports blocked, ensure that there are 
no leaks from the canister. If leaks exist, renew the 
canister. 

(9)  Remove the fuel check valve as previously 

described under the heading To Renew Fuel Check 
Valve. 

(10)  Blow through the check valve from the side 

that is connected to the fuel tank hose. Considerable 
resistance should be felt with only a small amount of 
air passing through the valve. If no resistance is felt or 
if the valve is blocked renew the fuel check valve. 

(11)  Blow air through the fuel check valve from 

the opposite end. There should be a smooth flow of air 
through the valve. If the valve is blocked, renew the 
fuel check valve. 

3.    AIR PREHEAT SYSTEM — 1.6 LITRE 

ENGINE 

DESCRIPTION 

To reduce emissions and improve drivability 

when the engine is cold, hot air is drawn into the air 
cleaner from a heat shield which partially surrounds 
the exhaust manifold.

 

When the ambient temperature is below 30°C, the 

thermal vacuum valve, which is located inside the air 
cleaner housing, allows vacuum to operate a servo 
actuated flap in the air cleaner intake duct. When the 
flap closes, hot air is drawn from the exhaust heat 
shield, through the hot air inlet tube into the air 
cleaner intake duct.

 

When the ambient temperature is above 30°C, 

the flap in the air cleaner intake duct opens allowing 
cool air to enter the air cleaner.

 

 

View of the air preheat system components. 1.6 liter 

engine. 

TO CHECK OPERATION

 

(1)  When the engine is cold, use a mirror to 

check that the passage from the hot air inlet tube is 
closed by the flap. 

(2)  Start and run the engine at approximately 

1 200 rpm. The hot air inlet passage should now be 
open, allowing hot air from the exhaust heat shield to 
be drawn into the air cleaner. 

(3)  Allow the engine to idle for fifteen minutes 

and inspect the position of the air cleaner intake flap. 
The flap should now be in the open position allowing 
cool air to be drawn into the air cleaner and shutting 
oft' air from the exhaust manifold heat shield. 

TO CHECK COMPONENTS

 

(1) Disconnect the vacuum hose from the servo 

unit and connect a vacuum pump to the unit.

 

When the vacuum is applied to the servo unit, the 

flap in the air cleaner intake duct should close.

 

When the vacuum is removed, the flap should 

open.

 

 

View of the air cleaner raised showing the engine 

ventilation hose and the thermal vacuum valve supply 

hose connection. 1.6 liter engine. 

120

 

Emission Control

 

If the flap does not operate as described, renew 

the air cleaner housing.

 

(2)  Disconnect the vacuum hose from the servo 

unit and connect it to a vacuum gauge. 

(3)  Start and run the engine at approximately 

1  200 rpm. If the engine is cold there should be 
vacuum. 

(4)  As  the  engine  temperature  increases  the 

vacuum should decrease to zero. 

If the vacuum gauge does not read as described, 

check that the vacuum supply hose is connected to the 
thermal vacuum valve and the throttle body.

 

If no fault is found, renew the thermal vacuum 

valve.

 

4.    EXHAUST CONTROL SYSTEM

 

DESCRIPTION

 

The exhaust system is the greatest source of 

pollutant emission from the internal combustion 
engine.

 

On the Pulsar range of vehicles covered by this 

manual, the exhaust control system consists of a 
catalytic converter and the engine management sys- 
tem. The engine management system constantly mon- 
itors the exhaust gases via an oxygen sensor located in 
the exhaust system. Fuel injection is then adjusted 
accordingly to give the minimum amount of exhaust 
emissions. Refer to the Fuel and Engine Management 
section for further information.

 

CATALYTIC CONVERTER

 

The catalytic converter, which is located in the 

exhaust system, converts hydrocarbons, oxides of 
nitrogen and carbon monoxide present in the exhaust 
gases into carbon dioxide, nitrogen, water and heat.

 

The catalytic converter does not require periodic 

maintenance or replacement under normal circum- 
stances. However, it can be damaged or poisoned by 
excessively high exhaust gas temperatures, raw fuel 
and the use of leaded fuel.

 

Installed view of the catalytic converter.

 

To prevent the use of leaded fuel, a small diam- 

eter fuel filler neck with a spring loaded trap door is 
used.

 

To prevent damage to the catalytic converter, the 

following precautions should be observed.

 

(1)  Do not operate the vehicle on leaded fuel. 
(2)  Do not push or tow start the vehicle. 
(3)  Do not allow the engine to idle for prolonged 

periods. 

(4)  Do not operate the vehicle if the engine is 

misfiring. 

(5)  Avoid running the vehicle out of fuel. 
(6)  Ensure that the engine oil is formulated to 

contain low phosphorous levels. 

To Inspect Catalytic Converter

 

(1)  Inspect the converter for dents and damage. 

If the converter is damaged, it should be renewed. 

(2)  Inspect the converter heat shield for damage 

and ensure that it is positioned correctly. Renew the 
converter heat shield if necessary. 

To Remove and Install 

To remove and install the catalytic converter, 

refer 
to the Exhaust System heading in the Engine section.