SECTION 6E2 EMISSION CONTROL - V8 ENGINE

CAUTION:

This vehicle will be equipped with a Supplemental Restraint System (SRS). A SRS will

consist of either seat belt pre-tensioners and a driver's side air bag, or seat belt pre-

tensioners and a driver's and front passenger's side air bags. Refer to CAUTIONS,

Section 12M, before performing any service operation on, or around any SRS

components, the steering mechanism or wiring. Failure to follow the CAUTIONS

could result in SRS deplo yment, resulting in possible p ersonal injury or unnecessary

SRS system repairs.

CAUTION:

This vehicle may be equipped with LPG (Liquefied Petroleum Gas). In the interests of

safety, the LPG fuel system should be isolated by turning 'OFF' the manual service

valve and then draining the LPG serv ice lines, before any service w ork is carried out

on the vehicle. Refer to the LPG leaflet included with the Owner's Handbook for

details or LPG Section 2 for more specific servicing information.

1. GENERAL INFORMATION

VT Series Models fitted with V8 engines are designed to comply with the requirements of Australian Design Rule,

ADR 37. In order to meet the low exhaust emission levels specified in ADR 37, these vehicles operate on unleaded

petrol and are fitted with a catalytic converter in the exhaust system. These vehicles also feature electronically

controlled fuel injection and ignition system.

In addition, these vehicles are fitted with the following emission control systems:

V8 ENGINE

ENGINE VENTILATION

EVAPORATIVE EMISSION CONTROL

THREE WAY CATALYTIC CONVERTER

1.1 VEHICLE EMISSION CONTROL INFORMATION LABEL

The Vehicle Emission Control Information Label,

refer to Figure 6E2-1, is located in the engine

compartment refer to Figure 6E2-2. The label

contains important engine tune conditions to

achieve the correct emission levels, and should be

referred to before making any adjustments.

Figure 6E2-1

Figure 6E2-2

1.2 EMISSIONS MANAGEMENT

All aspects of engine air/fuel ratio and spark timing are controlled by the Powertrain Control Module (PCM). The

mixture control is a closed loop system which incorporates dual oxygen sensors in the exhaust system engine

pipes. The Engine Ventilation system is not controlled by the PCM. However the Evaporative Emission Control

system is now controlled by the PCM through a canister purge solenoid valve. The PCM and its associated systems

are described in Section 6C2 POWERTRAIN MANAGEMENT - V8 ENGINE.

1.3 ENGINE VENTILATION

The engine ventilation system uses a Positive

Crankcase Ventilation (PCV) valve.

During normal driving conditions, crankcase vapours

are drawn into the inlet manifold via a PCV valve.

To stop a vacuum from forming inside the crankcase,

fresh air is admitted through the ventilation hose,

located between the throttle body and the right rocker

cover.

Manifold vacuum draws crankcase vapours through

the vapour/oil separator, located within the left roc ker

cover. The “maze” type separator prevents any oil

being admitted to the combustion process.

To maintain idle quality, the PCV valve restricts the

vapour flow when the intake manifold vacuum is

high.

If abnormal manifold vacuum conditions occur, the

system will allow excess vapours to flow through the

ventilation hose into the throttle body and be

consumed by the normal combustion process.

The engine ventilation system must be checked at

the time or distance intervals specified in the VT

Series Owner's Handbook.

The PCV valve is a non-serviceable item and must

be replaced if defective.

Figure 6E2-3

1.4 EVAPORATIVE EMISSION CONTROL

The Evaporative Emission Control System (EECS)

captures f uel vapours which would norm ally escape

from the fuel tank and enables them to be

consumed in the combustion process. The EECS

used on VT Series Models is the C storage method.

This method transfers fuel vapour from the fuel

tank to an activated carbon (charcoal) storage

canister to hold vapours when the vehicle is not

operating. When the engine is running, the fuel

vapour is purged f r om the ca rbon element by intake

air flow and consumed in the normal combustion

process. The fuel tank cap is not vented to

atmosphere, but is fitted with a valve to allow both

pressur e and vacuum r elief. The canis ter is a three

port design:

1. Atmospheric port (fresh air inlet)

2. Purge Port

3. Vapour inlet port

The fuel vapour is absorbed by the charcoal in the

canister. W hen the engine is running at idle speed,

air is drawn into the canister through the

atmospheric port at the top of the canister

assembly. The air mixes with the vapour and the

mixture is drawn into the intake manifold via the

canister purge line.

Figure 6E2-4

The purge port (3) on the c anister is controlled by a

PCM activated purge solenoid valve. The solenoid

valve controls the manifold vac uum s ignal from the

throttle body. The vapour inlet port (2) allows fuel

vapour to enter the canis ter from the f uel tank . T he

atmos pher ic port (1) allow fres h air to be dr awn into

the canister.

This system has a remote mounted canister purge

control solenoid valve. The PCM operates this

solenoid valve to control vacuum to the canister.

Under cold engine conditions, the solenoid valve is

turned OFF by the PCM, which blocks vacuum to

the canister and prevents purge.

The PCM turns ON the solenoid valve and allows

purge:

• When the engine coolant temperature is less

than 80° C, 3 minutes and 15 seconds after

engine start.

• W hen the engine c oolant temper ature is greater

than 80° C, 5 minutes after engine start.

• Engine is not in Dec el Fuel Cutof f Mode and the

throttle opening is less than 92%.

• Engine is in Closed Loop Fuel Mode.

The canister cannot be repaired, and is serviced

only as an assembly. Periodically check the

canister at the time or distance intervals specified

in the VT Series Owner's Handbook.

1. Atmospheric Port

2. Vapour Inlet Port

3. Purge Port

4. Liquid Trap

5. Volume Compensator and Filter

6. Diffuser

Figure 6E2-5

Figure 6E2-6

1. Throttle Body 4. Carbon Canister 7. Fuse F33

2. PCM 5. Fuel Tank 8. EFI Relay

3. PCM Terminal C4 6. Purge Solenoid Valve 9. Atmospheric Port

1.5 THREE-WAY CATALYTIC CONVERTER

PRINCIPLES OF OPERATION

Catalyst is the term used to describe substances which accelerate chemical reactions without themselves changing.

In the field of motor vehicle technology, the catalyst has the task of lowering the levels of pollutants, carbon

monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOX), in the exhaust gases by converting them into

harmless naturally occurring gases.

CO and HC are converted by oxidation with the oxygen (O2) contained in the exhaust gases into non-poisonous

carbon dioxide (CO2) and water vapour (H2O). To eliminate the oxides of nitrogen (NOX), the harmful carbon

monoxide which binds the oxygen in the exhaust gases is used as a reducing agent. The products of this reaction

are carbon dioxide (CO2) and nitrogen (N2). Together with oxygen, these two gases are components of the air that

we breathe.

The catalytic converter consists of a stainless steel housing enclosing a ceramic monolith. The monolith is an

extruded core of cordierite, a specially developed high temperature ceramic with approximately 160 cells/sq.cm. in

cross section. This gives the monolith a very large surface area for its mass. Distributed over the monolith surface is

a catalyst consisting of a combination of the precious metals, Platinum, Palladium and Rhodium.

Engine exhaust gases flow over the monolith and reactions with the catalysts occur. The converter is called a three-

way type because it simultaneously converts three components of exhaust gas (CO, HC and NOX) to harmless

natural gases.

Figure 6E2-7

Figure 6E2-8

The catalytic converter can only reduce exhaust

emissions if:-

a. The engine is designed for use with a

catalytic converter and unleaded petrol,

since lead contaminates the catalytic

coating and prevents it from functioning.

b. It is integrated in the exhaust system in

such a way that the exhaust emission

conversion occurs in the most effective

temperature range - in the vicinity of 600

degrees Celsius.

c. The catalysts function effectively within

certain air/f uel ratios only, cons equently the

air/fuel r atio supplied to the engine m ust be

controlled within strict limits for proper

emission conversion and long converter

life. This control is offered by operating

under a closed loop mixture control system,

with dual oxygen sensor s. For details of the

oxygen sensors, refer to Section 6C2

POWERTRAIN MANAGEMENT - V8

ENGINE.

The catalytic converter can be damaged, or

rendered ineffective, if operated outside the limits

of the closed loop mixture control system, or if the

engine burns excessive amounts of oil.

Figure 6E2-9

SERVICE NOTES

1. Never operate the vehicle with leaded petrol as the lead will contaminate the ceramic monolith.

2. Never drop the catalytic converter, as it will damage the ceramic monolith.

3. Do not allow water, oil or fuel to enter the converter as the ceramic monolith will be contaminated.

4. Do not use any engine additive that is not recommended by Holden. Many additives contain phosphorous,

which will contaminate the ceramic monolith.

5. In order to prevent the catalytic converter from overheating, the following sequence must be followed when

carrying out a cylinder balance test.

a. Maximum time each cylinder may be switched off is 8 seconds.

b. Pause for at least 8 seconds between each switch off.

c. If repeating a cylinder balance test, allow engine to idle for a least 60 seconds before retesting.

6. The vehicle must not be started by pushing or towing, as unburned fuel could reach the catalytic converter and

destroy the ceramic monolith. Always use jumper leads to start vehicle which has a flat or defective battery.

7. When carrying out a compression test, remove the EFI relay from the engine compartment relay housing, refer

Section 6A2 ENGINE MECHANICAL -V8 ENGINE. This prevents fuel injection and ignition during engine

cranking.

8. Do not drive vehicle for long periods with engine misfiring or with spark plug leads disconnected, as the

catalytic converter will overheat.

9. Do not coast downhill with engine misfiring or with spark plug leads disconnected.

10. Never re-use catalytic converter flange gaskets.

11. If the catalytic converter housing must be welded, use MIG or TIG with stainless steel wire. Do not use

oxy/acetylene welding, as damage to the monolith may result.

12. The catalytic converter is integrated with the exhaust system. For removal and installation instructions, refer to

Section 8B EXHAUST SYSTEM.

2. SERVICE OPERATIONS

2.1 POS I TIVE CRANKCASE VENTILATION VALVE

TEST

1. Start the engine and allow to idle.

2. Disconnect the PCV hose (1) from the left

rocker cover.

3. Place a finger over the end of the hose, and

check for vacuum. If there is no vacuum,

check for plugged hoses or inoperative PCV

valve.

4. Switch ignition off. Remove PCV valve from

hoses. Shake valve and listen for the rattle of

valve within. Replace the valve if it does not

rattle.

REPLACE

1. Disconnect the PCV valve hose from the left

rocker cover.

2. Disconnect the PCV valve from the throttle

body hose.

3. Install a new valve into the throttle body hose,

then connect the hose from the left rocker

cover to the valve.

Figure 6E2-10

2.2 EVAPORATIVE EMISSION CONTROL CANISTER

REMOVE

1. Disconnect fuel vapour inlet line (1) by using

the following procedure:

a. Grasp both sides of the quick-connect

fitting. Twist the connector 1/4 turn in

each direction in order to loosen any dirt

within the quick-connect fitting.

CAUTION:

Wear safety glasses when using compressed

air. b. Using compressed air, blow any dirt out

of the quick connect fitting.

Figure 6E2-11

c. Grasp the quick-connect fitting and push

toward the canister

d. Squeeze the quick-connect fitting to

release the retaining tabs, then pull back

on the connector to remove the vapour

inlet line (1) from the canister.

Figure 6E2-12

2. Disconnect fuel purge line (1) by using the

following procedure:

a. Grasp both sides of the quick-connect

fitting. Twist the connector 1/4 turn in

each direction in order to loosen any dirt

within the quick-connect fitting.

CAUTION:

Wear safety glasses when using compressed

air. b. Using compressed air, blow any dirt out

of the quick connect fitting.

Figure 6E2-13

c. Grasp the quick-connect fitting and push

toward the canister

d. Squeeze the quick-connect fitting to

release the retaining tabs, then pull back

on the connector to remove the fuel purge

line (1) from the canister.

3. Remove line from atmospheric port.

Figure 6E2-14

4. Loosen and remove canister retaining nut (1).

5. Remove canister from retaining stud, then

slide canister out of retainer (2).

Figure 6E2-15

REINSTALL

1. Reinstall canister into canister mounting

bracket (1) and over retaining stud.

2. Reinstall canister retaining nut (2) and hand

tighten.

3. Push canister toward center of vehicle and

tighten canister retaining nut to the correct

torque.

CANISTER RETAINING NUT 2.0 - 5.0

TORQUE SPECIFICATION Nm

Figure 6E2-16

4. Reinstall atmospheric port line (1).

5. Align fuel vapour purge line quick connector

(2) with fuel vapour purge line port then push

connector firmly onto port.

6. Align fuel vapour inlet line quick connector (3)

with fuel vapour inlet line port then push

connector firmly onto port.

7. Once installed, pull on each quick connect in

order to make sure the connections are secure

and locked in position.

Figure 6E2-17

SERVICE CHECKS

1. Remove canister as previously described in

this Section.

2. Shake canister. There should be no audible

sound of carbon movement.

3. Using low pressure compressed air (20-35

kPa), blow into the vapour inlet port (2) . Check

that air flows freely from the atmosphere port

(1).

Block the atmosphere port (1) and air should

flow from the purge line port (3).

4. If air flow through the purge line port (3) is

poor, clean the atmospheric filter by blocking

off the vapour inlet port (2) and blowing

compressed air at approximately 300 kPa

through purge line port (3). Recheck air flow

through filter as in Step 3. If air flow through

atmospheric port (1) is still poor, replace

canister.

5. Block the atmospheric port (1) and the purge

line port (3). Apply low pressure compressed

air (20-35 kPa) to the vapour inlet port (2). If

any air leak s f r om canis ter , i.e. around por ts or

seams, canister must be replaced.

Figure 6E2-18

2.3 CANISTER PURGE SOLENOID VALVE

REMOVE

1. Disconnect battery earth lead.

2. Remove engine dress covers.

3. Mark hoses on canister purge solenoid valve

(1 to carbon canister and 2 f rom throttle body),

and remove hoses from valve.

4. Pull up on solenoid wiring harness connector

tab and remove connector (3) from solenoid

valve (4).

Figure 6E2-19

5. Insert a thin blade screwdriver between

solenoid and solenoid bracket to release

retaining clip.

6. Remove solenoid from solenoid bracket.

Figure 6E2-20

REINSTALL

1. Reinstall canister purge solenoid valve onto

solenoid bracket and push down over retaining

clip.

NOTE:

Ensure retaining clip locks into place.

2. Reconnect hoses and wiring harness

connector to canister purge solenoid valve,

ensuring connections are correct.

3. Reinstall engine dress covers.

4. Reconnect battery earth.

VACUUM HOSE LAYOUT DIAGRAMS

Figure 6E2-21

1. Fuel Vapour inlet line 2. Fuel Vapour Purge Line 3. Atmospheric Vent Line

Figure 6E2-22

1. Vacuum Supply Line 2. Vacuum Supply Line to A/C 3. Vacuum Line to Water Valve

Figure 6E2-23

1. Vacuum Control Switch Supply. 2. Vacuum Line to Water Valve. 3. Vacuum Supply.

Figure 6E2-24

1. Vacuum Control Switch Supply. 2. Vacuum Line to Water Valve. 3. Vacuum Supply.

3. DIAGNOSIS

POSITIVE CRANKCASE VENTILATION

CONDITION PROBABLE CAUSE CORRECTIVE ACTION

Rough, slow idle or

stalling PCV valve blocked.

Blocked or damaged

ventilation hose.

Clean valve or replace.

Clean or replace hose.

Rough, fast idle or stalling PCV valve stuck in

intermediate position.

PCV valve leaking.

Clean valve or replace.

Check valve 'O' ring, replace if

necessary.

Check valve installation.

Excessive sludging or

diluting of oil Engine is not being vented. Check for clogged PCV valve

circuit and clogged ventilation

circuit.

For diagnosis of faults pertaining to vehicle performance, refer to Section 6C2 POWERTRAIN MANAGEMENT -

V8 ENGINE.

EVAPORATIVE EMISSION CONTROL

CONDITION PROBABLE CAUSE CORRECTIVE ACTION

Loss of fuel from filler cap Unsatisfactory sealing

between cap

and filler neck.

Malfunction of filler cap relief

valve.

Replace filler cap.

Replace fuel tank if filler neck

if damaged.

Replace filler cap

Loss of fuel from fuel

lines Loose line connection

Faulty or leaking vapour

separator

Secure connection.

Replace.

Loss of fuel from canister Fuel tank overfilled.

When the fuel warms up

during parking or warm

weather operation, excess

fuel is discharged into the

canister, flooding it.

Kinked hoses at filler neck

and vapour separator

reservoir.

Blocked, damaged or

disconnected purge valve at

canister.

Avoid overfilling of tank.

Clean hose. Replace

damaged hose. Install

correctly.

Replace canister.

Collapsed fuel tank or

pressure in tank Faulty fuel filler cap (in high

temperature operating

conditions some pressure

may normally be encountered

in the fuel tank).

Kinked hoses at filler neck

and vapour separator

reservoir

Blocked or kinked vent line

Defective canister (usually

internal blocked).

Purge solenoid valve is closed

causing canister to become

overloaded.

Replace filler cap.

Clean line. Replace damaged

line.

Replace canister.

Refer 6C2 POWERTRAIN

MANAGEMENT - V8

ENGINE.

Rough idle Improperly routed or

disconnected purge line.

Purge solenoid valve is open

or not receiving power.

Install purge line.

Refer 6C2 POWERTRAIN

MANAGEMENT - V8

ENGINE.

For diagnosis of faults pertaining to vehicle performance, refer to Section 6C2 POWERTRAIN MANAGEMENT -

V8 ENGINE.

4. SPECIAL TOOLS

TOOL NO. REF IN TEXT TOOL DESCRIPTION COMMENTS

J23738 - A HAND VACUUM PUMP PREVIOUSLY RELEASED

FOR 'V' AND 'J' CARS.