Engine Management – V6 – Service Operations Page 6C1-3–48
2.22 Spark Plugs
Service Precautions
1 Allow the engine to cool (to at least 50°C) before attempting to remove spark plugs. Attempting to remove spark
plugs from a hot engine may cause the plug / cylinder head threads to bind, resulting in tearing of the alloy cylinder
head threads.
2 Clean the spark plug recess area before removing any spark plug. Failure to do so could result in engine damage because of dirt or other foreign material entering the cylinder head or by the contamination of the cylinder head
threads. The contaminated threads may then prevent the correct seating of the new or replaced plug. If required,
use a thread chaser to clean the threads of any contamination where this is suspected.
3 Under no circumstances should the spark plug/s gap be adjusted. If the gap is not within specifications,
replace the spark plug.
Figure 6C1-3 – 66
Remove
1 Turn the ignition switch off.
2 Remove the ignition coil/s, refer to 2.15 Ignition Coil.
3 Using a suitable spark plug socket, loosen the spark plug slightly and then re-tighten to break away any carbon deposits on the threads.
Wear eye protection to avoid injury.
4 Loosen the spark plug once again one or two turns, then use compressed air to remove any foreign material that may otherwise enter the combustion chamber.
5 Remove the spark plug (1).
6 Repeat as required for the remaining spark plugs.
NOTE
Place each spark plug in the same order as that
of removal. This will enable any abnormal spark
plug condition to be identified with the cylinder.
NOTE
If the spark plugs are removed for an indefinite
period before installation, plug the spark plug
openings to prevent foreign particle ingress.
7 Repeat steps 2 to 5 for the remaining spark plugs as required.
Figure 6C1-3 – 67
Inspect
The spark plugs must not be re-gapped. If the gap of a spark plug is outside the specified range, replace the spark plug.
In addition, replace spark plugs that shows excessive dirt deposit or broken insulators.
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Engine Management – V6 – Service Operations Page 6C1-3–50
• plug/s overheating due to insufficient tightening (caused by combustion gases leaking past the threads).
Broken Insulator
Broken insulators are usually the result of improper installation or carelessness.
Breaks in the upper insulator can result from a poor fitting spark plug socket or impact. The cracked insulator may not
show up until oil or moisture penetrates the crack. The crack is often just below the crimped part of the shell and may not
be visible.
Breaks in the lower insulator often result from careless re-gapping and are usually visible.
This can also result from the plug operating too hot. For example, in periods of high speed operation or under heavy
loads.
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Engine Management – V6 – Service Operations Page 6C1-3–51
Analysis of Spark Plug Condition
Figure 6C1-3 – 69
Legend
1 Normal
2 Carbon Fouled
3 Oil Fouled
4 Deposit Fouling A 5 Deposit Fouling B
6 Deposit Fouling C
7 Detonation
8 Pre-ignition 9 Heat Shock Failure
10 Insufficient Installation Torque
Normal Operation (1)
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 (2)
Dry, fluffy black carbon deposits possibly due to poor ignition output, a weak coil, excessive idling or slow speeds under
light load. If spark plug temperatures remain too low for normal combustion, the deposits are not burned off.
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Engine Management – V6 – Service Operations Page 6C1-3–52
Oil Fouled (3)
W et, oily deposits with minor electrode wear possibly due to oil leaking past worn piston rings.
Breaking in a new or recently overhauled engine before the rings are fully seated may also result in this condition.
Deposit Fouling A (4)
Red brown, yellow and white coloured coatings on the insulator tip which are by-products of combustion. They come
from fuel and lubricating oil which generally contain additives. Most powdery deposits have no adverse effect on spark
plug operation, however, they may cause intermittent missing under severe operating conditions.
Deposit Fouling B (5)
Deposits similar to those identified in deposit fouling A (4). These are also by-products of combustion from fuel and
lubricating oil. Excessive valve stem clearances and / or defective intake valve seals allow too much oil to enter the
combustion chamber. The deposits will accumulate on the portion of the spark plug that projects into the chamber and
will be heaviest on the side facing the intake valve. If this condition is only detected in one or two cylinders, check the
valve stem seals.
Deposit Fouling C (6)
Most powdery deposits identified in deposit fouling A (4) have no adverse effect on the operation of the spark plug as
long as they remain powdery.
Under certain conditions of operation however, these deposits melt and form a shiny glaze coating on the insulator.
W hen hot, this acts as a good electrical conductor allowing the current to flow along the deposit instead of sparking
across the gap.
Detonation (7)
Commonly referred to as engine knock or pinging, detonation causes severe shocks inside the combustion chamber
causing damage to parts.
Pre-ignition (8)
Burnt or blistered insulator tip and badly eroded electrodes probably due to the excessive heat.
This is often caused by a cooling system blockage, sticking valves, improperly installed spark plugs or plugs that are the
wrong heat rating (too hot).
Sustained high speed with a heavy load can produce temperatures high enough to cause pre-ignition.
Heat Shock Failure (9)
A rapid increase in spark plug tip temperature under severe operating conditions can cause heat shock and result in
fractured insulators. This is a common cause of broken and cracked insulator tips.
Insufficient Installation Torque (10)
Poor contact between the spark plug and the cylinder head seat.
The lack of proper heat transfer that results from poor seat contact causes overheating of the spark plug. In many cases,
severe damage occurs. Dirty threads in the cylinder head can cause the plug to seize before it is seated.
Ensure the cylinder head and spark plug threads are free of deposits, burrs and scale before installation.
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Engine Management – V6 – Service Operations Page 6C1-3–57
3 Specifications
Accelerator Pedal Position Sensor 1
Type .....................................................Three wire potentiometer
Accelerator pedal at rest .................................. Less than 1.25 V
Accelerator pedal fully depressed .......................5.0 V maximum
Accelerator Pedal Position Sensor 2
Type .....................................................Three wire potentiometer
Accelerator pedal at rest .................................. Less than 1.25 V
Accelerator pedal fully depressed .......................5.0 V maximum
Camshaft Position (CMP) Sensor
Type ................................... Hall effect, interrupted ring triggered
Air gap ................................................................... 0.1 – 1.8 mm
Air gap adjustment ............................................... No adjustment
Crankshaft Position (CKP) Sensor
Type ....................................................... Inductive magnetic type
Coil resistance @ 20°C .......................................... 850 – 1040 Ω
Air gap ................................................................... 0.1 – 1.5 mm
Air gap adjustment ............................................... No adjustment
Engine Coolant Temperature Sensor
Type .......................................................... Negative temperature
................................................................... coefficient thermistor
Engine Coolant Temperature Vs Resistance
Temperature °C Resistance – Ohms ( Ω)
-40 40490 – 50136
-20 14096 – 16827
-10 8642 – 10152
0 5466 – 6326
20 2351 – 2649
25 1941 – 2173
40 1118 – 1231
60 573 – 618
80 313 – 332
100 182 – 191
120 109 – 116
140 68 – 74
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Engine Management – V6 – Service Operations Page 6C1-3–58
Engine Oil Level and Temperature Sensor
Level sensor type ....................................... Magnetic reed switch
Temperature sensor type .......................... Negative temperature
................................................................... coefficient thermistor
Engine Oil Temperature Vs Resistance
Temperature °C Resistance – Ohms ( Ω)
0 7570 – 8000
20 2351 – 2649
30 2225 – 2375
40 1118 – 1231
50 1050 – 1150
80 380 – 470
100 270 – 290
Evaporative Emission (EVAP) Canister Purge Valve
Type .............................................................................. Solenoid
Resistance @ 20°C...................................................... 24 – 28 Ω
Operating voltage................................................... 12.0 – 16.0 V
Engine Firing Order ..................................................................... 1, 2, 3, 4, 5, 6
Fuel Injector
Type .............................................................................. Solenoid
Fuel Injector Resistance @ 20°C ........................... 11.4 – 12.6 Ω
Heated Oxygen Sensor (HO2S) – Four wire
Type ...................................................... Four wire, planar sensor
Operating range (greater than 360°C) .................. 10 – 1000 mV
Closed loop operating range ................................. 300 – 600 mV
Heater resistance @ 20°C ....................................... 8.0 – 10.0 Ω
Heated Oxygen Sensor (HO2S) – Six W ire
Type ....................................... Six wire, wide band planar sensor
Heater resistance @ 20°C ....................................... 8.0 – 10.0 Ω
Intake Air Temperature (IAT) Sensor
Type .......................................................... Negative temperature
.................................................................. Coefficient thermistor
Intake Air Temperature Vs Resistance
Temperature °C Resistance – Ohms ( Ω)
-40 35140 – 43760
-20 12660 – 15120
-10 7943 – 9307
0 5119 – 5892
20 2290 – 2551
25 1900 –2100
40 1096 –1238
60 565 – 654
80 312 – 370
100 184 – 222
120 114 –141
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Engine Management – V6 – Service Operations Page 6C1-3–60
4 Assembly Lubricants
Camshaft Position (CMP) Sensor O-ring ........................................... Engine Oil
Crankshaft Position (CKP) Sensor .................................................... Engine Oil
Evaporative Emission (EVAP) Canister Purge Valve
Quick Connect Fitting ........................................................................ Engine Oil
Fuel Feed Hose Quick Connect Fitting .............................................. Engine Oil
Fuel Injector Seals............................................................................. Engine Oil
Heated Oxygen Sensor (HO2S) – All .............................. Anti-seize Compound
Ignition Coil Boot .......................................................................Talcum Powder
Ignition Coil Sealing Rubber .............................................................. Engine Oil
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Engine Management – V6 – Service Operations Page 6C1-3–61
5 Torque Specifications
Fuel Rail Attaching Bolt ............................................................... 8.0 – 12.0 Nm
Accelerator Pedal Position Sensor Support Bracket
Attaching Nut ............................................................................... 8.5 – 11.5 Nm
Air Cleaner Lower Housing Attaching Bolt................................. 18.0 – 22.0 Nm
Barometric Pressure Sensor Attaching Bolt ................................ 8.0 – 12.0 Nm
Camshaft Position Sensor Attaching Bolt .................................... 8.0 – 12.0 Nm
Crankshaft Position Sensor Attaching Bolt .................................. 8.0 – 12.0 Nm
Engine Coolant Temperature Sensor ................................................... 22.0 Nm
Engine Control Module Attaching Bolt ......................................... 8.0 – 12.0 Nm
Ground Terminal Attaching Screw.......................................................... 4.5 Nm
Engine Control Module Bracket Assembly
Attaching bolt (6mm Bolt) ............................................................ 8.0 – 12.0 Nm
Engine Control Module Bracket Assembly
Attaching bolt (8mm Bolt) .......................................................... 20.0 – 25.0 Nm
Engine Oil Pressure Sensor ...................................................... 12.0 – 14.0 Nm
Heated Oxygen Sensor ............................................................. 40.0 – 50.0 Nm
Ignition Coil Attaching Bolt........................................................... 7.0 – 11.0 Nm
Air Intake Duct Retaining Clamp ................................................... 1.5 – 2.5 Nm
Knock Sensor Attaching Bolt ..................................................... 21.0 – 25.0 Nm
Mass Air Flow Sensor Attaching Nut ............................................. 1.8 – 2.2 Nm
Spark Plug ................................................................................. 16.0 – 20.0 Nm
Throttle Body Assembly Attaching Bolt........................................ 8.0 – 12.0 Nm
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