SECTION 6D1-3 IGNITION SYSTEM - V6 ENGINE &

V6 SUPERCHARGED ENGINE

CAUTION:

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

consist of either seat belt pre-tensio ners 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 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

The ignition system for VT Models with V6 engines is a high energy 'distributor less' Direct Ignition System (D.I.S.).

This system uses a 'waste spark' method of spark distribution.

Each cylinder is paired with its opposing cylinder in the firing order, so that one cylinder on compression fires

simultaneously w ith its opposing cylinder on exhaust stroke. (Since the cylinder on exhaust requires very little of the

available voltage to fire its spark plug, most of the voltage is used to fire the spark plug on the cylinder on

compression).

The process reverses when the cylinders reverse roles, i.e. if cylinder No. 1 is on compression and cylinder No. 4 is

on exhaust, most of the voltage is used to fire No. 1 spark plug. With 360 degree rotation of the crankshaft, No. 4

will be on compression and No. 1 will be on exhaust, therefore, No. 4 spark plug will receive the majority of the

voltage.

1.1 GENERAL DESCRIPTION

The D.I.S. System com prises an electronic coil and

ignition module assembly, Dual Crank Sensor

(crankshaft position sensor), Camshaft Position

Sensor, Electronic Spark Control (ESC) system,

spark plugs, spark plug leads and the engine

management Powertrain Control Module (PCM).

The coil pack and ignition module assembly are

mounted on a bracket attached to the front of the

left hand cylinder head. Figure 6D1-3-1 refers to

the standard V6 and Figure 6D1-3-2 refers to the

supercharged V6.

The coil pack consists of three separate and

interchangeable ignition coil assemblies. These

coils operate in the same manner as conventional

ignition coils. Three coils are needed, as each coil

fires for two cylinders.

The ignition module is located under the coil pack

and is connected to the PCM by a 14 pin wiring

harness connector.

The ignition module controls the primary circuit to

the coils, turning them ON and OFF, and controls

spark timing below 450 RPM and if PCM bypass

circuit becomes open or earthed. Refer to Section

6C1 POWERTRAIN MANAGEMENT - V6

ENGINE. The ignition module is non-repairable. If

the module must be replaced, the three coil

assemblies must be transferred to the new module.

Cylinder numbering is nominated on the top of

each coil assembly and on the top surface of the

module assembly.

Figure 6D1-3-1

Figure 6D1-3-2

Figure 6D1-3-3

Figure 6D1-3-4

The crankshaft position sensor incorporates two

Hall effect device sensors and a centre mounted

magnet. Two interrupter rings pass through the

slots in the sensor and provide timing information,

crankshaft position and RPM to the PCM.

The crankshaft position sensor is mounted in a

bracket bolted to the front of the cylinder block,

near the crankshaft balancer.

Figure 6D1-3-5

The interrupter rings are assembled to the rear of

the crankshaft balancer assembly.

Figure 6D1-3-6

Windows in the interrupter rings activate the Hall

sensors as they provide a path for the magnetic

field between the sensor's transducer and the

centre mounted magnet. When the Hall effect

sensor is activated, it earths the signal line to the

ignition module, reducing the crank signal line's

applied voltage, which is interpreted as a crank

signal. Due to the way the crank signal is created,

the signal circuit is always either at a high or low

voltage (square wave signal).

The outer interrupter ring has eighteen, 10 degree

windows and eighteen, 10 degree teeth. The inner

ring has three windows, each of different width, a

10 degree window, 20 degree window and a 30

degree window.

With the rotation of the interrupter rings through the

Hall effect sensors, the combination of the sensors

output signals uniquely identify each of the three

cylinder pairs at a specific point in the crankshaft

rotation.

For further details on the operation of the

crank s haf t position sensor and the interr upter r ings,

refer to Section 6C1 POWERTRAIN

MANAGEMENT - V6 ENGINE.

Figure 6D1-3-7

To prevent the possibility of foreign matter being

caught up between the crankshaft position sensor

and the interrupter rings of the crank shaft balancer

assembly, a sensor shield is fitted to the front of

the engine.

The shield must be removed before removing the

crankshaft position sensor.

The Electronic Spark Control (ESC) system used

on V6 engines, modifies (retards) the spark

advance when detonation occurs. T he retard m ode

is held for 20 seconds after which the spar k contr ol

will revert back to the Electronic Spark Timing

(EST) control of the PCM.

The ESC system us es a knock s ensor to detec t the

presence and intensity of engine detonation or

spark knock. The knock sensor is mounted in the

right hand side of the cylinder block, behind the oil

pressure sender unit.

The output of the knock sensor is an electrical

signal which is sent to a c ontroller, mounted on the

PCM PROM.

The controller processes the sensor signal into a

command signal to adjust the EST. T he process is

continuous so that the presence of detonation is

monitored and controlled.

If the knock sensor should fail, the ignition timing

will retard, but at a calibrated, fixed amount

determined by the PCM. Figure 6D1-3-8

Should the controller fail, one of two conditions

could apply, no retard or full retard (10 degrees

max.).

For additional inform ation on the ESC system , ref er

to Section 6C1 POWERTRAIN MANAGEMENT -

V6 ENGINE.

Resistor type, tapered seat spark plugs are used in

the V6 engine, no gasket is used on these tapered

seat plugs.

Fig. 6D1-3-9 illust rates and explains the s park plug

letter coding for NGK examples only.

Always replac e plugs with the correct plug listed on

the Vehicle Emission Control Information Label.

The label also lists the correct spark plug gap.

Refer to Fig. 6D1-3-10 for the location of the

Vehicle Emission Control Information Label.

Figure 6D1-3-9

The Vehicle Emission Control Information label is

located on the left hand side of the radiator upper

shroud.

Figure 6D1-3-10

2. SERVICE OPERATIONS

2.1 SPARK PLUG LEADS - V6 ENGINE

REMOVE AND REINSTALL

Use care when removing spark plug lead boots

from spark plugs.

NOTE:

Pull on the boot only, DO NOT pull by the lead.

When reinstalling plug leads, route leads correctly

and through the proper retainers. Failure to route

the leads corr ectly can res ult in the lead/s chaffing,

burning, or causing crossfiring of the plugs or

shorting of the leads to ground.

NOTE:

All spark plug leads and coil terminals are

numbered to correspond to the cylinder numbering.

Special care should be exercised when reinstalling

spark plug lead boots to ensure that the metal

terminal within the boot is fully seated on the spark

plug terminal and that the boot has not moved on

the lead. If boot movement has occurred, the boot

will give a false visual impression of being fully

seated.

Also ensure that the metal tabs at the base of the

boot heat shields are completely seated over the

spark plug hex, also that heat shields remain

seated against bump stops at cable end of boot.

The following figures illustrates the spark plug lead

routing and retention.

Figure 6D1-3-11

TEST

Remove leads, taking note of precautions as

previously outlined.

Connect an ohmmeter capable of reading to

50,000 ohms across each lead. The ohmmeter

should register less than 10,000 ohms resistance

for leads connected to cylinders 1, 3 and 5 and less

than 17,000 ohms for leads connected to cylinders

2, 4 and 6.

Replace any lead/s that has higher than specified

resistance.

Techline

SPARK PLUG LEAD ROUTING - V6 ENGINE

Figure 6D1-3-12

SPARK PLUG LEAD RETENTION - V6 ENGINE

Figure 6D1-3-13

2.2 SPARK PLUG LEADS - V6 S UP E RCHARGED ENGINE

The procedure to rem ove, test and reinstall the spark plug leads on V6 supercharged engines is the sam e as non

supercharged V6 engines, noting the revised spark plug lead routing and retention, refer to Fig. 6D1-3-12 and

Fig. 6D1-3-13 in this Section.

Theref ore when rem oving, testing or reinstalling the spark plug leads on V6 superc harged engines, ref er to the non

supercharged procedures in this Section.

SPARK PLUG LEAD ROUTING - V6 SUPERCHARGED ENGINE

Figure 6D1-3-14

Techline

SPARK PLUG LEAD RETENTION - V6 SUPERCHARGED ENGINE

Figure 6D1-3-15

2.3 SPARK PLUGS

REMOVE

1. Disconnect spark plug leads from spark plugs,

refer to 2.1 SPARK PLUG LEADS - V6

ENGINE in this Section.

2. Unscrew and remove spark plugs using a 16

mm spark plug socket.

3. Plug spark plug holes with rag to prevent

foreign matter entering combustion chambers.

CLEAN AND ADJUST

1. Carefully inspect spark plug insulators and

electrodes. Replace any plug with cracked or

broken insulation or loose electrodes.

Refer to 3.1 SPARK PLUG DIAGNOSIS in

this Section for identification of spark plug

condition.

2. If spark plugs are oily, clean with degreasing

agent and dry with compressed air.

NOTE:

When removing spark plugs, plac e them in order of

removal. This will enable a check of individual

cylinders to be made. Engine condition to be

assessed by viewing the colour of the plug insulator

and electrode wear.

Should one or two spark plug insulators appear

different to the other spark plugs, check engine

compression (refer to Section 6A1-1 ENGINE

MECHANICAL - V6 ENGINE).

3. Clean spark plugs using a sand blast type

cleaning machine as per manufacturer's

instructions.

4. Inspect spark plugs again for defects which

may not have been apparent before cleaning.

5. Ensure that spark plug threads are clean and

in good order.

6. Use round wire feeler gauges to check gap

between spark plug electrodes.

7. Adjust gap to correct specification by bending

outer electrode.

Figure 6D1-3-16

SPARK PLUG GAP 1.5 mm

REINSTALL

1. Remove rag from spark plug holes.

2. Reinstall spark plugs and tighten to the cor r ect

torque specif ication using a 16 m m spark plug

socket.

SPARK PLUG

TORQUE SPECIFICATION 15 - 25

3. Reinstall spark plug leads.

Techline

2.4 IGNITION COIL AND MODULE ASSEMBLY

REMOVE

1. Remove battery earth lead.

2. Remove spark plug leads from coil terminals,

noting lead numbering with reference to coil

terminal numbers.

NOTE:

All spark plug leads and coil terminals are numbered to

correspond to the cylinder numbering.

If cylinder numbering does not appear on top of any

coil assembly, refer to cylinder numbering on the

module (refer to Fig 6D1-3-4 in this Section).

3. From beneath powertrain harnes s retainer at f ront

of coil and m odule assembly, gently pull down on

the retainer lower locating tangs and pull retainer

from the coil and module assembly.

4. Loosen bolt attaching 14 - pin wiring harness

connecter to module, pull connector from module.

5. Remove coil and module assembly bracket to

cylinder head attaching bolts and rem ove coil and

module assembly. Figure 6D1-3-17

6. Remove coil and module assembly bracket to

cylinder head attaching bolts and rem ove coil and

module assembly.

Figure 6D1-3-18

TEST

Visually inspect coil/s for any signs of external

damage or spark tracking.

Using an ohmmeter, check coil primary winding

resistance by probing into terminals from the

underside of the coil assembly.

Correct resistance of the ignition coil primary

winding must be between 0.3 and 1.5 ohms.

NOTE:

Some ohmmeter lead probes may be too large to

contact the primary winding connections inside the

coil housing, so as an aid to checking primary

winding resistance, wrap a thin piece of wire

around each ohmmeter lead probe. It is imperative

that the contact between the ohmmeter lead probe

and the wire be first clas s to ens ur e the acc ur acy of

the ohmmeter reading.

Figure 6D1-3-19

Check resistance across coil secondary winding

terminals.

Correct resistance of the ignition coil secondary

winding must be between 5000 and 7000 ohms.

Replace coil assembly if not to specification.

Figure 6D1-3-20

REINSTALL

1. Assemble coil and module assembly to

cylinder head attaching bolts. Tighten

attaching bolts to the correct torque

specification.

COIL AND MODULE ASSEMBLY

BRACKET TO CYLINDER HEAD

ATTACHING BOLT

TORQUE SPECIFICATION

40 - 50 Nm

2. Refit spark plug leads to coil terminals,

ensuring correct lead to coil terminal

relationship.

3. Reconnect battery earth lead, start engine and

ensure engine operates correctly.

WI RING HARNESS MODULE BOLT

TORQUE SPECIFICATION 0.6 - 1.2

4. Refit powertrain harness retainer to front of

coil and module assembly, ensuring that it is

securely retained.

5. Reconnect battery earth lead, start engine and

ensure engine operates correctly.

2.5 CRANKSHAFT POSITION SENSOR

REMOVE

1. Remove battery earth lead.

2. Remove crankshaft balancer, refer to

Section 6A1-1 ENGINE MECHANICAL - V6

ENGINE.

3. Using a fine bladed s c rewdriver , c arefully lever

back engine harness connector retaining tang

from crankshaft position sensor and pull

connector from sensor.

Figure 6D1-3-21

4. Using a screwdriver behind sensor shield,

lever each corner of shield from front cover

studs, remove shield.

Figure 6D1-3-22

5. Remove sensor bracket to front cover

attaching studs and remove sensor assembly.

Figure 6D1-3-23

REINSTALL

1. Clean threads of sensor to front cover

attaching studs. Apply Loctite 242 or

equivalent (Holden Specification HN 1256

Class 2, Type 2) to threads of studs.

Install sens or ass em bly onto front cover dowel

pin and install attaching studs.

2. Tighten sensor bracket to front cover

attaching studs to the correct torque

specification.

SENSOR BRACKET TO FRONT

COVER ATTACHING STUD

TORQUE SPECIFICATION 20 - 30 Nm

3. Reinstall sensor shield onto front cover studs,

ensuring shield retainers fully engage over

ends of studs.

Reinstall engine harness connector to sensor,

ensuring that connector locking tang engages

fully on sensor.

4. Visually inspect interrupter rings for any

damage or distortion.

Figure 6D1-3-24

5. Reinstall crankshaft balancer, refer Section

6A1 ENGINE MECHANICAL - V6 ENGINE.

NOTE:

Do not install drive belt at this stage.

6. Rotate crankshaft so as to check that

interrupter rings do not contact sensor.

If the interrupter rings contact the sensor at

any point during balancer rotation, the

interrupter rings have excessive runout and

the balancer assembly must be replaced.

7. Reinstall drive belt and battery earth lead.

Start engine and ensure engine operates

correctly.

2.6 KNOCK SE NS OR

WARNING:

It must be noted that the knock sensors screw

into the cylinder block coolant jackets.

If removing the knock sensors with the engine

coolant still hot, ensure extreme caution is

taken so as to prevent any serious personal

injury due to hot coolant draining from the

cylinder block.

REMOVE

NOTE:

Extreme care should be exercised when handling

the knock sensor so as not to drop it on a hard

surface. If this should happen, the sensor internal

components can be damaged.

1. Allow engine to cool to ambient temperature

(less than 50° C), then remove radiator cap.

2. Disconnect battery earth lead.

3. Raise front of vehicle and support on safety

stands. Refer to Section 0A GENERAL

INFORMATION for location of jack points.

4. Squeeze together 'wide ends' of knock sensor

wiring harness connector (connector is oval

shaped) and pull connector from sensor.

Figure 6D1-3-25

5. Place a suitable drain tray beneath the knock

sensor location.

6. Remove the knock sensor heat shield

attaching bolts and heat shields.

7. Using a 22 mm socket, universal joint and

suitable length socket bars, loosen and

remove sensor from cylinder block, taking

extrem e care to avoid any draining coolant if it

is hot.

Figure 6D1-3-26

REINSTALL

1. Ensure that the threads in the sensor

mounting hole in cylinder block are clean.

2. If reinstalling original sensor, inspect sealant

on sensor threads. If worn away, apply a light

coating of Loctite 242 (Holden Specification

HN 1256 Class 2, Type 2) to sensor threads.

NOTE:

On a new sensor, do not apply sealant to threads

as threads are coated with a sealant during

production. Applying additional sealant will affect

the sensor's ability to detect engine knock.

3. Install sensor and tighten to the corr ect torque

specification.

CAUTION:

Ensure that knock sensor is never over

tightened as damage to the sensor can occur.

ESC KNOCK

SENSOR TIGHTENING

TORQUE SPECIFICATION 16 - 22 Nm

4. Reconnect wiring harness connector to

sensor. Ensure that connector is securely

fitted onto sensor.

5. If removed, reinstall knock sensor heat shield

and attaching bolts. Tighten bolts to the

correct torque specification.

KNOCK SENSOR HEAT SHIELD

ATTACHING BOLT

TORQUE SPECIFICATION 25 - 35 Nm

6. Refill cooling system and pressure test for

leaks, refer to Section 6B1 ENGINE

COOLING - V6 ENGINE.

7. Reconnect battery earth lead.

3. DIAGNOSIS

For diagnosis of the ignition system, refer to Section 6C1 POWERTRAIN MANAGEMENT - V6 ENGINE.

3.1 SPARK PLUG DIAGNOSIS

Worn or dirty plugs may give satisfactory operation while the vehicle is idling, but under load they may break down.

Faulty plugs can cause; poor fuel economy, power loss, loss of speed, hard starting and general poor engine

performance.

Spark plugs may also fail due to carbon fouling, excessive gap or a broken insulator.

Fouled plugs are indicated by black carbon deposits. The black deposits are usually the result of slow-speed driving

and short runs where the optimum engine operating temperature is seldom reached. Worn piston rings, faulty

ignition, over rich fuel mixture and spark plugs which are too cold will also result in carbon deposits.

Excessive electrode wear, usually indicates that the engine is operating at high speeds or levels that are

consistently greater than normal or that a plug which is too hot is being used. Electrode wear may also be the result

of plug overheating, caused by combustion gases leaking past the threads due to insufficient tightening of the spark

plug. Excessively lean fuel mixture will also result in excessive electrode wear.

Broken insulators are usually the result of improper installation or careless re-gapping. Broken upper insulators

usually result from a poor fitting spark plug socket or an outside blow. The cracked insulator may not show up

initially, but will, as soon as oil or moisture penetrates the crack. The crack is often just below the crimped part of

the shell and may not be visible.

Broken lower insulators usually result from careless re-gapping and generally are visible. This type of break may

result from the plug operating too 'HOT', which may happen in periods of high speed operation or under heavy

loads. When re-gapping a spark plug, always make the gap adjustment by bending the earth (side) electrode. Do

not use spark plugs with broken insulators.

When replacing spark plugs, use only genuine spark plugs of the correct heat range.

ANALYSIS OF SPARK PLUG CONDITION

Figure 6D1-3-27

NORMAL OPERATION

Refer to Fig. 6D1-3-27

Brown or greyish-tan deposits and slight electrode wear indicate correct spark plug heat range and mixed periods of

high and low speed driving.

CARBON FOULED (SOOTED)

Refer to Fig. 6D1-3-27

Dry, fluffy black carbon (soot) deposits are due to poor ignition output, weak coil or faulty spark plug leads.

Excessive idling, slow speeds under light load also can keep spark plug temperatures so low that normal

combustion deposits are not burned off.

OIL FOULED

Refer to Fig. 6D1-3-27

Wet, oily deposits with minor electrode wear may be caused by oil leaking past worn piston rings. 'Break in' of a new

or recently overhauled engine before rings are fully seated may also result in this condition.

DEPOSIT FOULING "A"

Refer to Fig. 6D1-3-27

Red brown, yellow and white coloured coatings on the insulator tip. These coatings are by-products of combustion

and come from the fuel and lubricating oil, both of which today generally contain additives. Most powdery deposits

have no adverse effect on spark plug operation; however, they may cause intermittent missing under severe

operating conditions, especially at high speeds and heavy load.

DEPOSIT FOULING "B"

Refer to Fig. 6D1-3-27

Deposits are similar to those identified as DEPOSIT FOULING "A". These deposits are by-products of combustion

and come from the fuel and lubricating oil. Excessive valve stem clearances and/or defective intake valve seals will

allow excessive oil to enter the combustion chamber. The deposits will accumulate on the portion of the spark plug

projecting into the chamber and will be heaviest on the side facing the intake valve. Defective seals should be

suspected when the condition is found in only one or two cylinders.

DEPOSIT FOULING "C"

Refer to Fig. 6D1-3-27

Most powdery deposits identified in DEPOSIT FOULING "A", have no adverse effect on the operation of the spark

plug as long as they remain in the powdery state. However, under certain conditions of operation, these deposits

melt and form a shiny glaze coating on the insulator which, when hot, acts as a good electrical conductor. This

allows the current to follow the deposits instead of jumping the gap, thus shorting out the spark plug.

DETONATION

Refer to Fig. 6D1-3-27

Commonly referred to as engine knock or ‘ping’, detonation causes severe shock inside the combustion chamber to

the adjacent parts which include spark plugs.

PRE-IGNITION

Refer to Fig. 6D1-3-27

Causes burned or blistered insulator tip and badly eroded electrodes. Excessive overheating is indicated. Cooling

system blockage or sticking valves are common causes of pre-ignition. Spark plugs which are the wrong (too hot)

heat range, or not properly installed are also a possible cause. Sustained high speed, heavy load service can

produce high temperatures which will cause pre-ignition.

HEAT SHOCK FAILURE

Refer to Fig. 6D1-3-27

A common cause of broken and cracked insulator tips. Rapid increase in tip temperature under severe operating

conditions causes the heat shock and a fracture results.

Another common cause of chipped or broken insulator tips is carelessness in re-gapping, by either bending the

centre electrode to adjust the gap, or allowing the gapping tool to exert force against the tip of the centre electrode

or insulator when bending the outer electrode to adjust the gap.

INSUFFICIENT INSTALLATION TORQUE

Refer to Fig. 6D1-3-27

Poor contact between the spark plug and the engine seat. The lack of proper heat transfer, resulting from poor seat

contact, causes overheating of the spark plug and, in many cases, severe damage as shown. Dirty threads in the

cylinder head can also result in the plug seizing before it is seated.

THREAD SEIZURE

Refer to Fig. 6D1-3-27

Recommended installation torque may be obtained without taper seat engagement in cy linder head. Operation of an

engine with this type of installation may result in spark plug overheating, causing possible damage to the spark plug

or engine.

Always ensure cy linder head and spark plug threads are free of deposits, burrs and scale.

4. SPECIFICATIONS

Ignition Coil Primary Winding Resistance 0.3 - 1.5 ohm

Ignition Coil Secondary Winding Resistance 5000 - 7000 ohm

Sealant Loctite 242, Holden

Specification HN 1256

Class 2, Type 2

Spark Plug (V6) Original Equipment NGK BPR6EFS-15

Service Replacement AC R42LTS6

Spark Plug Gap 1.5 mm

Spark Plug (V6 supercharged) Original Equipment AC 41-919

Spark Plug Gap 1.5mm +0 - 0.5

Ignition Lead Resistance (V6) Left Hand Side Less than 10,000 ohms

Right Hand Side Less than 27,000 ohms

Ignition Lead Resistance (V6 supercharged) Left Hand Side Less than 10,000 ohms

Right Hand Side Less than 17,000 ohms

5. TORQUE WRENCH SPECIFI CATIONS

Coil Securing Screws 4 - 5

Coil and Module Assembly to Support Securing Nuts 8 - 11

Coil and Module Assembly Support to Cylinder Head

Attaching Bolts 40 - 50

Wiring Harness to Module Bolt 0.6 - 1.2

Crankshaft Position Sensor to Front Cover Attaching

Studs 20 - 30

Spark Plugs 15 - 25

Knock Sensor 16 - 22

Knock Sensor Heat Shield Attaching Bolt 25 - 35