1 hour ago, varaderoguy said:

Even more worrying from my perspective is the bit that was missing from plug no 1.....where has it gone?  Has it gone into the cylinder?  Have you managed to retrieve the broken-off part? 

 

Sounds like the oil seals are on their way out.  Oil on plug....never good - and shows distress on that cylinder.  Compression test good first start....I think you will find its down on pressure - which means new piston rings as a minimum...

 

Couldnt find anything in the cylinder last year, this year when I shine a torch down you see a shiny spot on top of the piston exactly below where the spark plug sits. Cant see any debris but potentially been punched into the piston now.

 

Just find it curious the car runs perfectly between spark plugs getting burnt out, trying to figure out what's happening first. If the spark plug burning out is causing unburnt fuel to wash the bore and lift oil (if that's possible), or if the oil getting on to the spark plug is burning out the spark plug.

Just a few random thoughts, pure speculation so don't take anything as gospel

 

1. Majority of oil seems to be in No. 1 cylinder, suggesting some cylinder wall damage or ring issue (White smoke is part burnt oil)

 

2. According to various plug assessment sites the plug damage is likely to sustained pre ignition occurring. (Possibly due to presence of debris and excess oil in chamber) would explain how plug has been 'knocked" loose.

 

3. Shiny point on crown may be due to sparking straight down or a physical contact point 

 

Are the plugs genuine and the correct heat range, reach etc?

 

1st point of call is pressure testing (wet and dry).  A borescope inspection camera would be useful to look for chamber damage and debris.

 

But I'd be resigned to the fact the head needs to come off for a proper appraisal.

 

Or simply sell it on. (Somewhat immoral in my book unless you declare the issue).

Edited 6 May, 20206 yr by xman
Removed ref to former owner

I think pressure test first.and boroscope...but oil washing past the cylinder head gasket is a good pointer that the cylinder will need to come out and be maintained. Spark plug will put up with abuse of oil in cylinder but eventually it will fail. Lets hope No1 doesn't have scoring on the bore.

Further thought just occurred, if the plug works loose and oil gets up the threads, the plug loses its ability to dissipate heat to the cylinder head and will overheat greatly and possibly lead to preignition. Its important that the plug and cylinder head threads are dry when installing plugs, no grease to be used. And check the torque with a torque wrench. Maybe you should check the spark plug condition / tightness every 2-3000 miles if you arent going to investigate further for now 

 

On further thought still, maybe the plug was simply not correctly tightened when you had the car mapped. Mapping may have made preignition more likely due to running hotter and damage occurred over a period of time.

Edited 6 May, 20206 yr by xman

1 hour ago, xman said:

Are the plugs genuine and the correct heat range, reach etc?

 

1st point of call is pressure testing (wet and dry).  A borescope inspection camera would be useful to look for chamber damage and debris.

 

But I'd be resigned to the fact the head needs to come off for a proper appraisal.

 

Or simply sell it on. (Somewhat immoral in my book unless you declare the issue).

 

Plugs are NGK ones, ordered via the reg number from the local factors. I did wonder about them but I fitted them all at the same time, and only number 1 cylinder is showing any issue at all, other 3 looked perfectly fine which led me away from blaming them.

 

I wouldnt feel right selling it on tbh, not for how much someone would be paying for it.

 

1 hour ago, varaderoguy said:

I think pressure test first.and boroscope...but oil washing past the cylinder head gasket is a good pointer that the cylinder will need to come out and be maintained. Spark plug will put up with abuse of oil in cylinder but eventually it will fail. Lets hope No1 doesn't have scoring on the bore.

 

I've got a camera at work that I can stick down to have a look, just be a case of getting time to do it when I'm there.

 

I had the same issue last year with the burnt out plug, but put it down to not changing the plugs before the remap. New plugs went in and everything started running sweet so thought I'd sussed it until now. If there has been a deeper issue this whole time then I suspect it's already too late.

 

1 hour ago, xman said:

Further thought just occurred, if the plug works loose and oil gets up the threads, the plug loses its ability to dissipate heat to the cylinder head and will overheat greatly and possibly lead to preignition. Its important that the plug and cylinder head threads are dry when installing plugs, no grease to be used. And check the torque with a torque wrench. Maybe you should check the spark plug condition / tightness every 2-3000 miles if you arent going to investigate further for now 

 

On further thought still, maybe the plug was simply not correctly tightened when you had the car mapped. Mapping may have made preignition more likely due to running hotter and damage occurred over a period of time.

 

The plugs weren't out for the map, which is daft thinking back. It ran for around 6 months after the map before I got the issue first, and that came after about 6 months of driving it without issue before the map.

 

I replaced all four almost exactly a year ago, 3 of them are still tight while number 1 has come loose.

 

So it goes.

 

Bought car - Feb 18

Remap - Sep 18

First burnt out spark plug - May 19

Second burnt out, and now slack, spark plug - May 20.

 

In total I've done around 10k miles.

 

The whole time I've suffered from excessive oil consumption compared to what youd expect, having to top up the dipstick every 3 months roughly.

 

I fitted the plugs again last night, and have down 8 miles and theres no sign of any fault. Which baffles me.

@varaderoguy @xman

 

Checked compression in cylinder 1 and 4.

 

2 and 3 coils are stuck in and cant remove them without breaking so waiting on new ones coming before doing that.

 

Cylinder 1 - ~150 psi

 

Cylinder 4 - ~155 psi

Edited 6 May, 20206 yr by Saints92

Hopefully those compression figures are fine, the tester is a bit old and might have a small leak.

 

My boss reckons the figures are fine, and my issue is overfuelling. Suggests I go back to the company that mapped it and either get the map removed, or eased right off, to see if that affects it.

Edited 6 May, 20206 yr by Saints92

Just to remind you that you should be running 99 octane fuel on a remap. That reduces likelyhood of preignition (aka pinking).

Is this map from a well known respected tuner?

 

2 minutes ago, xman said:

Just to remind you that you should be running 99 octane fuel on a remap. That reduces likelyhood of preignition (aka pinking).

Is this map from a well known respected tuner?

 

 

Only ever run the car on Tesco Momentum, even before the remap.

 

And he is incredibly well known around here and has been for decades. I got first hand experience off a couple of friends before I went to him and they were all complimentary of what hes done on their cars. Only issue is he might be closed just now as I cant get a hold of him.

 

Take it those compression figures are fine?

Just now, Saints92 said:

 

Take it those compression figures are fine?

As your car is burning some oil they could be essentially "wet' figures and may disguise bore wear. Borescope is next step to visually inspect.

 

To remove coils and avoid expensive boot damage you really need the correct tool, this one I think, T10530

 

11 minutes ago, xman said:

As your car is burning some oil they could be essentially "wet' figures and may disguise bore wear. Borescope is next step to visually inspect.

 

I'd just got my hopes up it was fine aswell 😅

 

Tried our camera down the hole but its just a bit too big to fit completely down, the brief view I got with the light on the end of it made it looks fairly damage less down there, and my piston doesnt have anything burnt into/a hole forming, I've potentially been tricked by a simple reflection.

I would get a standard map back on the car. Perhaps a fresh map from Skoda or anyone who has access to the database to ensure it is totally bacj to stock. Might also be worth getting any other modules updated at the same time whilst it is in. I would also get your car live data mapped to see what the car is doing under load. 

It does seem odd it is always that one cylinder. How many miles had your car done when you purchased it?

54 minutes ago, Ecomatt said:

I would get a standard map back on the car. Perhaps a fresh map from Skoda or anyone who has access to the database to ensure it is totally bacj to stock. Might also be worth getting any other modules updated at the same time whilst it is in. I would also get your car live data mapped to see what the car is doing under load. 

It does seem odd it is always that one cylinder. How many miles had your car done when you purchased it?

 

Purely from memory around 66k miles, and I'm now about 10k on top of that.

12 hours ago, Saints92 said:

 

Purely from memory around 66k miles, and I'm now about 10k on top of that.

If had done 66k before you got it then there are two options here. Either this happened to the last owner and he/she sold it on and kept quiet. Or the car ran fine till the map was applied. I personally would get the car reverted back to standard so you have a baseline to work from. Perhaps run it for 500 miles and pull the plugs to check the colour of the tip.

^^Agree

4 hours ago, Ecomatt said:

If had done 66k before you got it then there are two options here. Either this happened to the last owner and he/she sold it on and kept quiet. Or the car ran fine till the map was applied. I personally would get the car reverted back to standard so you have a baseline to work from. Perhaps run it for 500 miles and pull the plugs to check the colour of the tip.

 

4 hours ago, xman said:

^^Agree

 

Yeah definitely feels like the best next step.

 

Seems like the place that mapped it is shut, just get a recorded message about coronavirus when I phone up.

 

Has anyone got any experience with getting a main dealer to revert it back to the stock map? Can imagine some places being funny about doing it but have zero experience of it at all.

Skoda should sort it no problem. They will just plug it in to their computer and it will copy the map to your car. Might be worth getting the other modules updated whilst you there.

1 hour ago, Ecomatt said:

Skoda should sort it no problem. They will just plug it in to their computer and it will copy the map to your car. Might be worth getting the other modules updated whilst you there.

 

Cheers.

 

I'll try and get in touch with the mapper every day from now until Monday, I'm just wanting to confirm with him it's the map causing the issue as he should really know exactly where to look for the issue, and then make plans to go to Skoda to see if they can revert it back.

 

Using my wife's car just to prevent any potential damage so can wait until I can get in touch with him if needs be.