Here is a couple of responses from the MK5 GTI forum:

 

• I would do a compression test to be sure.  Overboosting isn't a good sign.   The oil is not far enough up the plug to cause a misfire, in fact it looks like it's come up through the plug threads rather than dripping down from a leaking gasket.
• ^^^What he said^^^
  
  I suspect there was a pool of oil which has seeped down the plugs causing the threads to look as they do upon removal. You'd have enough smoke to fill the whole street if there was enough oil in the bores to do that to the plugs.
  
  You have both under and overboost codes..... have you changed any hardware (i.e. the wastegate actuator) or fiddled with the pre-load since it was mapped? If not then they've not done a good enough job with the software or you've developed a fault that needs sorting. Underboosting at 60mph in top and overboosting at 100mph means requested vs actual load isn't right
  
  Having just read the opening post properly, the clattering sound when depressing the accelerator does not sound good at all...... More investigation needed.... Compression test, oil pressure test, scope the bores etc.
   

Yes, I'm not sure everyone is totally on the same page there. Although I agree with some of the content of the replies.

 

Why mk5 GTI, you know the Mk5 GTI was the earlier revision engine, different design. Are they talking about the same engine or are you in a mk6 sub forum.  I'd have gone with a mk6 gti forum as they should have more set ups similar to yours..

 

I also think there are signs the oil has come up the threads in common with one of your other posters. And that is a sure sign of excess oil in the cylinder and that WILL cause mis firing of the plug INSIDE the cylinder due to electrode contamination. I'm not sure why there is text in that reply that suggests the opposite. It is like he is expecting the oil seeping on the outside of the coil pack to be the cause of a misfire. Completely off track IMO. 

 

Anyway, not much more I can add to anything here beyond what I've said. Need some more diagnosis or information for me to be of any further use. There is no point for me critiquing all the other responses from other forums. I would say be careful and use some logic in evaluating advice.

Edited 30 May, 20179 yr by TheClient

Thank you all for contributing, its greatly appreciated.

 

I'm just trying to arrange which garage/indy has capacity to take it on this week!

Edited 30 May, 20179 yr by Awesam

Unless the plug was loose (was it?), there's a gas-tight seal which shouldn't let anything upwards out of the cylinder, gases or oil. I'd have to agree with that oil on the plug threads having arrived there as the plug was undone, from the puddle formed from leakage above. Whether or not it was the cause of the misfire, I couldn't say, but if enough oil gets around the plug insulator (top bit, outside the combustion chamber) it will start to cause tracking of the HT and misfiring, especially when oil is old/contaminated. Having said that, it appears that the puddle didn't even reach the rubber 'gaiter' within the coilpack 'stem' that should help prevent contamination of the external part of the insulator.

 

I can't comment on the boost faults as I know bugger all about that stuff.

 

It would be a good investment to ensure the engine is compression tested before any rectification work on the camcover leak was begun, in  my opinion.

Edited 30 May, 20179 yr by Wino

I'd like to see a close up of the plug condition around the insulator and electrodes too I think.  

OK, I'll invest in a compression testing gauge, they don't seem too expensive and should be able to carry it out in the next day or two.

 

Which fuses to I need to pull out? 

 

I've replaced the old with a new, but i still have it - do you want me to take a close up on the electrode? 

 

 

 

Edited 30 May, 20179 yr by Awesam

If you want to, but if you are booked in somewhere, so you may prefer to just leave it and let them run diagnostics? That said a few tools of your own never go astray.

 

Same with the spark plug photo, you may prefer to leave it now.  If you do take a photo, there is some very good information in this link I just came across on searching, try matching to your plugs esp no 4 that has been the problem.

 

It can be hard taking a decent photo of the plugs at the electrode end. You need good light and it needs to be against a light background ideally. A like a piece of paper as the background can help and you have to make sure the focus is on the right part.

 

http://www.cd-group.com/Components/ngk-tips.html

 

Got a reply from one of the garages, they are suggesting it's the cam carrier sealant, saying it will take 8 hours to do that as they need to remove the timing chain. 

As for the other issues, they will need to carry out a compression test and take it from there. 

Waiting to hear back from Shark. 

 

In the meanwhile here are some pics of the sparkplug

 

Yes, as I mentioned the cam cover is a big job, my recollection was 5 hours +, so maybe 8 hours is in ball park.  I don't think that stand alone job is your primary concern here. But given the way the other things a looking, it may need to be done anyway as a part of other work.

 

I'm sorry to say, but that plug looks terrible, it looks fouled and will be creating a short to ground, there is so much carbon around the tip I can (edit: not) make out the differentiation of the insulator / electrode. If you compare to the article on spark plug condition I linked yesterday, you will see what I mean.

 

So I am not surprised by a misfire fault. So a new plug would fix that, but does not fix the underlying cause and if the cylinder is out of tolerance on compression, it will still not fire properly. Edit: and the stress on this cylinder and others if similar may have caused premature coil pack failure also.

 

I am concerned about the condition of that cylinder.

 

Let us know how you go, once investigated further. 

 

Also, has the spark plug compression washer fallen off?

 

Edit: these were my old plugs at 5.5 years / 38k for compare and contrast.

 

 

Edited 31 May, 20179 yr by TheClient

 what a difference!  So I suspect mines have been damaged to dry fouling.

 

Yes you are right, the compression washer has fallen off! I never noticed that.

 

Going to get it transported to Shark tomorrow however they wont be able to look at it until Tuesday!

 

Was thinking could it be the diverter valve?

Diverter valve could be related to one of your boost pressure tolerance codes, have those boost codes always been there?

 

Was the washer missing when the spark plug was in the cylinder head, has it fallen off and still sitting in the spark plug recess acting as a duplicate (not good) or did it just fall off after removal?

 

Do all the plugs, in all the cylinders, look like that one posted?

 

Easy check: Have you looked at the condition of the air cleaner?

 

For the plug to be that fouled, it has to be oil burn or serious over fuelling (injector or other fuel delivery or air problem) but I would have thought o2 sensors would be reporting the over fuelling. 

 

In summary, I think you've got a few things going on.

 

 

Edited 31 May, 20179 yr by TheClient

35 minutes ago, Awesam said:

 what a difference!  So I suspect mines have been damaged to dry fouling.

 

Yes you are right, the compression washer has fallen off! I never noticed that.

 

Going to get it transported to Shark tomorrow however they wont be able to look at it until Tuesday!

 

Was thinking could it be the diverter valve?

 

Sorry to keep sticking my nose in. If you do need a new DV, I have a spare unused and boxed rev G that I bought but didn't need in the end.

 

Also, given you're running a highly tuned car, you may want to consider the GFB DV+ addon too.

Edited 31 May, 20179 yr by planehazza

I've checked service invoices and the DV has been changed.  

 

As for the washer I can't remember when it fell off or is still sitting in the recess.

 

I didn't check the rest of the plugs! 

 

Harry, thanks I'll let you know if I need it also, what's a rev G?

Just now, Awesam said:

I've checked service invoices and the DV has been changed.  

 

As for the washer I can't remember when it fell off or is still sitting in the recess.

 

I didn't check the rest of the plugs! 

 

Harry, thanks I'll let you know if I need it also, what's a rev G?

 

Just means it's the latest one.  It uses a diaphragm rather than the piston (rev C).

Now booked to be transported to Shark on Monday! 

 

I'm just hoping that this isn't a very expensive repair i.e. £000's! 

 

As for the Air Cleaner - did you mean the air filter? If it has an ITG aftermarket kit on it, which may need a good clean!

Edited 31 May, 20179 yr by Awesam

Yes, Air filter. If it is significantly clogged / dirty. It will be restricting air flow.

 

The missing washer may hold some of the answers on the oil pushed up or down through the threads and the plug would not seal very well without a washer. Two washers would not be ideal either.

 

I recommend you mention to shark so they can check there is no duplicate compression washer when removing no 4.  Also, make sure you give them the plug removed to look at.

 

Fingers crossed but these engines are not that cheap to work on unless it is something simple.. If it is stripping and rebuilding even limited parts of the internals it will exceed your threshold very quickly.

 

This thread has me worries now. Upon removing my plugs, I was greeted with this bad news. The left image is of the left most plug (driver side) and the right I'd what the rest of them look like. 

 

 

Edited 31 May, 20179 yr by Awesam

18 minutes ago, planehazza said:

This thread has me worries now. Upon removing my plugs, I was greeted with this bad news. The left image is of the left most plug (driver side) and the right I'd what the rest of them look like. 

 

Take a photo of the 'bad' one at the same angle as the other one, so we can see the insulator around the electrode.  I think I can see a sliver of it in your photo looking clean and OK, but it's hard to tell from that shot.  If it is clean, I'd say you (just) have a similar slight 'weep' from the camcover seal.

Edited 31 May, 20179 yr by Wino

Just thinking ahead, does the water pump need changing at some point? 

13 hours ago, Wino said:

 

Take a photo of the 'bad' one at the same angle as the other one, so we can see the insulator around the electrode.  I think I can see a sliver of it in your photo looking clean and OK, but it's hard to tell from that shot.  If it is clean, I'd say you (just) have a similar slight 'weep' from the camcover seal.

 

https://goo.gl/photos/ZSaCNuobyoNYexU8A

 

Here are all 4. Can't remember which is the worst, as I foolishly cleaned the oil off after taking that first image.  The tips look fairly consistent thankfully.

Got compression tester today, will do the checks either tonight or tomorrow and report back. Which fuse(s) do i need to remove for the fuel pump?

this will also allow me to see if the sparkplug compression on Cylinder 4 is still there or not!

 

Reading up on some of the error codes, I'm hoping it's a DV which has gone along with the cam cover seals! Will know more on Tuesday/Wednesday next week.

On 31. 5. 2017 at 13:47, Awesam said:

I've checked service invoices and the DV has been changed.  

 

As for the washer I can't remember when it fell off or is still sitting in the recess.

 

I didn't check the rest of the plugs! 

 

Harry, thanks I'll let you know if I need it also, what's a rev G?

 

Already on first photo the washer is missing

https://www.briskoda.net/forums/topic/433232-help-replacing-an-injector/?do=findComment&comment=4877170

Those washers made so it never fall off, especially not when squashed at first assembly. Someone has done it realy badly, the washers is taken off intentionally ...

 

Change only all spark plugs and keep driving, do not let them to take top head cover off. When it does not help, the EA888 pistons+rings issue must be solved

 

Regarding fuse when checking compression, check this

https://www.briskoda.net/forums/topic/426100-superb-oil-consumption/?do=findComment&comment=4834018

or

https://www.briskoda.net/forums/topic/426782-18tsi-decoke-and-catch-can-queries/?do=findComment&comment=4845468

 

Note: Engine oil temperature at least 30 °C

 

Edited 2 June, 20179 yr by rayx

The engine has been replaced due to the timing chain issues.   Will find out next week if it is the piston & rings issue.

 

I haven't driven the car for over a week now to restrict any damage which may have occurred already.   

I've bought a new set of sparkplugs, will get them installed when any other work becomes apparent.

Update! Started the car and all is OK! 

I cleared the fault codes, no more misfiring. I took it for a quick spin and push it a bit and no issues. 

 

Ran VCDs scan again and the only issue to come back is the regarding boost pressure. 

 

Engine did sound slightly louder to me but that could me being paranoid. 

 

Anyway it's still going to Shark to have a look at on Monday.