Chris
Premium Member
Registered: 21st Sep 99
User status: Offline
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HT lead break down, hows the miss on higher revs?
Look for white dust on the lead caused to HT arcs
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AK
Member
Registered: 5th Jul 00
Location: Aberdeen City
User status: Offline
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I'd never even consider a 6 in a turbo car  Scared they'd end up like pauls with their tips missing.
If it works it works though....
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Dave
Member
Registered: 26th Feb 01
Location: Lancs
User status: Offline
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VAG 1.8t's run a 6 as standard but it seems to be common to change to 7 when running extra power.
Two plug breakages in quick succession, sounds like Paul may have dodged a bullet though, assuming the miss is nothing serious.
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Paul_J
Member
Registered: 6th Jun 02
Location: London
User status: Offline
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All I'm hoping is that when I do the compression test, it's fine and that the plug may have been like that for a while and it's just something else.
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3CorsaMeal
Member
Registered: 11th Apr 02
User status: Offline
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I took one out once and most of the white bit had fallen off. Car has been alright though.
I reckon a valve will be broken tbh.
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Online
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What is it with plus failing this week.
Foreign object in the bore wouldn't cause the misfire.
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Shrek
Member
Registered: 2nd Nov 06
Location: Berkshire
User status: Offline
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quote:
Originally posted by Ian
What is it with plus failing this week.
Foreign object in the bore wouldn't cause the misfire.
Really? Even if its jacked a valve open? Or broken the edge of a valve or damaged the valve seat? Or even taken a chunk out the piston crown? Ive seen the effects of a broken plug in a bore and the resulting damage was terrible. Head, Piston, Block, Valves etc etc.
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Paul_J
Member
Registered: 6th Jun 02
Location: London
User status: Offline
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I must admit, I kinda feel Ian may be on to something.
I came home parked the car, at that moment no mis fire at all... perfectly fine. Then started car in the morning and had this misfire.
Could it just be, that the plug was fucked already? and it's just a co-incidence I noticed it now, when something else is playing up.
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broster
Premium Member
Registered: 6th Dec 02
Location: Drives: E39
User status: Offline
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so when its warm the misfire goes?
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Paul_J
Member
Registered: 6th Jun 02
Location: London
User status: Offline
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Not really allowed it to get warm broster, what's your thinking?
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Shrek
Member
Registered: 2nd Nov 06
Location: Berkshire
User status: Offline
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quote:
Originally posted by Paul_J
Not really allowed it to get warm broster, what's your thinking?
How bad is the misfire? Is it a hesitation or a definate cylinder not firing? Any tapping or knocking?
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daymoon
Premium Member
Registered: 1st Aug 08
Location: Selby, North Yorkshire
User status: Offline
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When I had same happen to me, I was driving and the car suddenly lost most of the power. I drove it for good 30 miles as well to get home.
After replacing the plugs car run fine apart from slight popping if I pressed accelerator to the floor and released it quickly.
That stuff on the plugs is fairly soft so I doubt it would make any damage tbh...
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gavin18787
Premium Member
Registered: 22nd Feb 05
Location: Basildon, Essex
User status: Offline
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shame you got the plugs already I found a place that does a set for £30 
going to give mine a service when it warms up
Drives supercharged Tec with torque  
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Online
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quote:
Originally posted by Shrek
Really? Even if its jacked a valve open? Or broken the edge of a valve or damaged the valve seat? Or even taken a chunk out the piston crown? Ive seen the effects of a broken plug in a bore and the resulting damage was terrible. Head, Piston, Block, Valves etc etc.
What I mean is, there must be incidental damage as per your list or something else by coincidence for there to a misfire, ie. that might be quite bad, get a look in there and don't run it.
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Online
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quote:
Originally posted by Paul_J
Could it just be, that the plug was fucked already? and it's just a co-incidence I noticed it now, when something else is playing up.
Possibly, although that plug probably wouldn't have been doing its job.
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broster
Premium Member
Registered: 6th Dec 02
Location: Drives: E39
User status: Offline
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Chances are that the broken plug could have damaged the valve seat, so now it won't seal hence the misfire. Or it could be the fact the coil pack has packed up, do they run individual coils?
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alan-g-w
Member
Registered: 9th Nov 07
Location: Glasgow
User status: Offline
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quote:
Originally posted by Shrek
quote:
Originally posted by Ian
What is it with plus failing this week.
Foreign object in the bore wouldn't cause the misfire.
Really? Even if its jacked a valve open? Or broken the edge of a valve or damaged the valve seat? Or even taken a chunk out the piston crown? Ive seen the effects of a broken plug in a bore and the resulting damage was terrible. Head, Piston, Block, Valves etc etc.
I'd be assuming the worst, as in the above unfortunately. The misfire, with the old plugs, could have been caused by the piece of the old plug getting jammed between the valve and the valve seat whilst the engine was running - as said, this would cause the valve to not seat properly causing a misfire. Changing the plugs won't have an effect on that obviously so you're still getting the misfire.
When it runs well without the misfire you might find that the valve's just been sooted up enough as well as heated up and expanded enough to make it seat - when it cools down it might contract that tiny little bit causing it not to seat properly. It's a grim possibility but the first thing I'd be doing is making sure the bore's clear anyway
Hope I'm wrong though mate
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Paul_J
Member
Registered: 6th Jun 02
Location: London
User status: Offline
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Plot thickens...
Compression check seemed okay, about 220-230 across all 4 cylinders.
Mis fire still happening, smell of fuel present after car runs a while... the new spark plug in the hole where the fucked spark plug once sat is completely clean, and the other 3 are dirtied up...
... I'm starting to think failing coil on that cylinder?
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alan-g-w
Member
Registered: 9th Nov 07
Location: Glasgow
User status: Offline
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Good to hear compression's sound
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Dave
Member
Registered: 26th Feb 01
Location: Lancs
User status: Offline
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Does it have individual coils that you can pull while the engine is running?
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Paul_J
Member
Registered: 6th Jun 02
Location: London
User status: Offline
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yes
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Warren G
Member
Registered: 14th May 06
Location: Kent
User status: Offline
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swap coils over, the disconnect one at a time
see if the misfire moves with the coil...
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RS6
Member
Registered: 5th Nov 03
Location: with MJ
User status: Offline
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happened to my corsa c spark plug broke up and fell inside the engine, had it rebuilt but never sounded right sold it soon after [/cheerful]
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Paul_J
Member
Registered: 6th Jun 02
Location: London
User status: Offline
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Yeah warren I'll swap the coils over tommorrow, but not sure how I can really see where the mis fire is moving as I don't have the car on a reader
best I can actually do ... is that the new plugs are all dirtied up already except for the one with the dodgy coil. So swapping the coils over, if the clean plug gets dirty, it suggests that's what was wrong and I'll go get a new coil
[Edited on 09-02-2012 by Paul_J]
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Warren G
Member
Registered: 14th May 06
Location: Kent
User status: Offline
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you unplug two coils you will know thats its only run on two
start by unplugging the one where the plugs gone - no engine note change then its that out misfiring
unplug another - your hear the difference....
now swap the suspected faulty coil with another, and see if the missfire goes to that cylinder...
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