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CanadaSpark plugs
Fuel Additives
- Appearance: Reddish/brown or purple?deposits/coloration on the core nose?insulator
- Cause: Use of fuel additives
- Effect: Misfire. Normally additives are?non-conductive; however, some are?and if the deposit build up is excessive?it can create an earth leakage path for?the spark
- Remedy: Replace spark plugs and?ensure that any additives used are?compatible?with the engine manufacturer’s ignition?and emission systems and added in the correct proportion?
Worn-out Spark Plug
- Appearance: Centre and/or ground?electrodes are rounded and the gap?is excessive
- Cause: General wear (spark plug has?come to the end of its life). However,?the greyish tan/white colour indicates?that the plug is the correct heat range?and also that the fuel/ignition systems?and engine are generally in good?condition
- Effect: An increased gap will multiply?the workload on the ignition system and?may cause misfire, poor fuel economy,?and damage to other ignition?components.
- Remedy: Replacement is recommended?with new plug of the same heat range
Ash Deposits
- Appearance: Light brown deposits?encrusted on the centre and/or ground?electrode
- Cause: Often due to excessive fuel (or?oil) additives, however, general engine?wear can have a similar effect?on the spark plug
- Effect: Ash deposits can ‘shield’ the?spark, leading to misfire problems
- Remedy: Ensure plug is of the proper?heat range and check for engine wear
Pre-ignition
- Appearance: Melting (or partial melting)?of the ground and/or central electrode
- Cause: Spark plug too hot, air fuel?mixture excessively lean, incorrect?ignition advance, defective exhaust?re-circulation system, faulty detonation?sensor, cross induction in the spark plug?leads or worn engine components
- Effect: In extreme cases engine damage?will result
- Remedy: Identify the cause and rectify.?Replace spark plugs in line with?manufacturer’s recommendation
Corona Discharge Stain
- Appearance: Discoloration of the?ceramic insulator, near to the shell
- Cause: Particles of oil/gas (in the spark?plug well), becoming attracted to the?ceramic by the magnetic field created?by the high voltage current flowing?through the spark plug
- Effect: Not detrimental to spark plug?operation
- Remedy: Ensure that spark plug “well”?is clean when installing new spark plugs
Overheating
- Appearance: Chalky white insulator?(with no tan colouring) pitted or blistered?electrodes. In some cases the insulator?will begin to turn grey or dark blue
- Cause: Improper heat range plug, lean?air fuel mixture, incorrect ignition timing,?insufficient plug tightening torque and?general engine overheating
- Effect: General poor running conditions
- Remedy: Identify the cause of?overheating and rectify. Replace spark?plugs in line with manufacturer’s?recommended heat range
Oil Fouling
- Appearance: Firing end of spark plug is?‘wet’ with lubricating oil
- Cause: Usually a sign of advanced?engine wear (excessive volumes of oil?in the combustion chamber), oil fouling?can also be caused by a fault in the?crankcase breather system
- Effect: Misfire due to oil deposits?covering the firing end of the plug?preventing the spark from ‘jumping?the gap’
- Remedy: Rectify the cause of excessive?oil in the combustion chamber and?replace spark plugs
Cold/333体育(CHINA)官方网站bon Fouling
官方网站bonFouling-1530262601447.png "333体育(CHINA)官方网站bonFouling")
- Appearance: Soft, black, sooty deposits?on the firing end of the plug
- Cause: Rich air-fuel mixture, weak?ignition, spark plug too cold or repetitive?short journeys
- Effect: 333体育(CHINA)官方网站bon deposits are conductive?and can create earth leakage paths,?often resulting in misfire problems?which can lead to catalyst damage
- Remedy: Check fuel & ignition systems,?general engine performance and driving?style before plug replacement. Confirm?that the spark plug (part number) is?correct for the application
Flash Over
- Appearance: Black burn marks (carbon?tracks) running vertically down the?spark plug insulator towards the shell
- Cause: Current discharge from the top?terminal of the spark plug, down the?outside of the insulator to earth; due to poor fitting/worn spark plug boot
- Effect: Engine misfire
- Remedy: Replace the affected plug(s)?and plug lead(s)
Detonation
- Appearance: Light detonation will cause?black/grey spots on the insulator or?ground electrode. Severe detonation can?crack or even break the insulator or?ground electrode
- Cause: Abnormal combustion, causing?pressure spikes/shock waves in the?combustion chamber. Can result from:?inoperative exhaust gas re-circulation?system, defective detonation sensor,?lean air fuel mix, incorrect fuel octane?rating or spark advance and loose fitted?spark plugs
- Effect: Misfire and/or general poor/?uneven running which may result in?engine damage
- Remedy: Identify the cause and replace?the spark plugs
Spark Plug Tightening
- Appearance: Spark plug gasket has?not been sufficiently crushed (see?photographs)
- Cause: Incorrect tightening of the?spark plug
- Effect: If the plug is too loose,correct?heat dissipation will be prevented,?resulting inoverheating of the plug?which can lead to pre-ignition or?detonation problems. Conversely, if the?plug is too tight, damage may result to?the insulator and internal components?causing operating problems
- Remedy: Tighten spark plugs to?the manufacturer’s recommended?torque value
Normal Spark Plug Wear/Operation
- Appearance: Greyish tan to white colour?around the insulator, at the firing end
- Cause: Confirms that the spark plug is?the appropriate heat range and has been?firing correctly. Also indicates that the?fuel and ignition systems are working?efficiently and the engine is?mechanically sound
- Remedy: None required other than to?check the spark plug gap and replace?in line with manufacturer’s?recommendations
Fuel Additives
- Appearance: Reddish/brown or purple?deposits/coloration on the core nose?insulator
- Cause: Use of fuel additives
- Effect: Misfire. Normally additives are?non-conductive; however, some are?and if the deposit build up is excessive?it can create an earth leakage path for?the spark
- Remedy: Replace spark plugs and?ensure that any additives used are?compatible?with the engine manufacturer’s ignition?and emission systems and added in the correct proportion?
Worn-out Spark Plug
- Appearance: Centre and/or ground?electrodes are rounded and the gap?is excessive
- Cause: General wear (spark plug has?come to the end of its life). However,?the greyish tan/white colour indicates?that the plug is the correct heat range?and also that the fuel/ignition systems?and engine are generally in good?condition
- Effect: An increased gap will multiply?the workload on the ignition system and?may cause misfire, poor fuel economy,?and damage to other ignition?components.
- Remedy: Replacement is recommended?with new plug of the same heat range
Ash Deposits
- Appearance: Light brown deposits?encrusted on the centre and/or ground?electrode
- Cause: Often due to excessive fuel (or?oil) additives, however, general engine?wear can have a similar effect?on the spark plug
- Effect: Ash deposits can ‘shield’ the?spark, leading to misfire problems
- Remedy: Ensure plug is of the proper?heat range and check for engine wear
Pre-ignition
- Appearance: Melting (or partial melting)?of the ground and/or central electrode
- Cause: Spark plug too hot, air fuel?mixture excessively lean, incorrect?ignition advance, defective exhaust?re-circulation system, faulty detonation?sensor, cross induction in the spark plug?leads or worn engine components
- Effect: In extreme cases engine damage?will result
- Remedy: Identify the cause and rectify.?Replace spark plugs in line with?manufacturer’s recommendation
Corona Discharge Stain
- Appearance: Discoloration of the?ceramic insulator, near to the shell
- Cause: Particles of oil/gas (in the spark?plug well), becoming attracted to the?ceramic by the magnetic field created?by the high voltage current flowing?through the spark plug
- Effect: Not detrimental to spark plug?operation
- Remedy: Ensure that spark plug “well”?is clean when installing new spark plugs
Overheating
- Appearance: Chalky white insulator?(with no tan colouring) pitted or blistered?electrodes. In some cases the insulator?will begin to turn grey or dark blue
- Cause: Improper heat range plug, lean?air fuel mixture, incorrect ignition timing,?insufficient plug tightening torque and?general engine overheating
- Effect: General poor running conditions
- Remedy: Identify the cause of?overheating and rectify. Replace spark?plugs in line with manufacturer’s?recommended heat range
Oil Fouling
- Appearance: Firing end of spark plug is?‘wet’ with lubricating oil
- Cause: Usually a sign of advanced?engine wear (excessive volumes of oil?in the combustion chamber), oil fouling?can also be caused by a fault in the?crankcase breather system
- Effect: Misfire due to oil deposits?covering the firing end of the plug?preventing the spark from ‘jumping?the gap’
- Remedy: Rectify the cause of excessive?oil in the combustion chamber and?replace spark plugs
Cold/333体育(CHINA)官方网站bon Fouling
- Appearance: Soft, black, sooty deposits?on the firing end of the plug
- Cause: Rich air-fuel mixture, weak?ignition, spark plug too cold or repetitive?short journeys
- Effect: 333体育(CHINA)官方网站bon deposits are conductive?and can create earth leakage paths,?often resulting in misfire problems?which can lead to catalyst damage
- Remedy: Check fuel & ignition systems,?general engine performance and driving?style before plug replacement. Confirm?that the spark plug (part number) is?correct for the application
Flash Over
- Appearance: Black burn marks (carbon?tracks) running vertically down the?spark plug insulator towards the shell
- Cause: Current discharge from the top?terminal of the spark plug, down the?outside of the insulator to earth; due to poor fitting/worn spark plug boot
- Effect: Engine misfire
- Remedy: Replace the affected plug(s)?and plug lead(s)
Detonation
- Appearance: Light detonation will cause?black/grey spots on the insulator or?ground electrode. Severe detonation can?crack or even break the insulator or?ground electrode
- Cause: Abnormal combustion, causing?pressure spikes/shock waves in the?combustion chamber. Can result from:?inoperative exhaust gas re-circulation?system, defective detonation sensor,?lean air fuel mix, incorrect fuel octane?rating or spark advance and loose fitted?spark plugs
- Effect: Misfire and/or general poor/?uneven running which may result in?engine damage
- Remedy: Identify the cause and replace?the spark plugs
Spark Plug Tightening
- Appearance: Spark plug gasket has?not been sufficiently crushed (see?photographs)
- Cause: Incorrect tightening of the?spark plug
- Effect: If the plug is too loose,correct?heat dissipation will be prevented,?resulting inoverheating of the plug?which can lead to pre-ignition or?detonation problems. Conversely, if the?plug is too tight, damage may result to?the insulator and internal components?causing operating problems
- Remedy: Tighten spark plugs to?the manufacturer’s recommended?torque value
Normal Spark Plug Wear/Operation
- Appearance: Greyish tan to white colour?around the insulator, at the firing end
- Cause: Confirms that the spark plug is?the appropriate heat range and has been?firing correctly. Also indicates that the?fuel and ignition systems are working?efficiently and the engine is?mechanically sound
- Remedy: None required other than to?check the spark plug gap and replace?in line with manufacturer’s?recommendations