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Lumpy fast idle following misfire.


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There is one more thing to consider. Running very rich above 5kRPM, high temps and high stress - too much for poor old FST...

 

EDIT: That is only my personal opinion, not some statement of fact!

Edited by Jabozuma
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<snip>

What has Redlining to do with it.?

<snip>

Sorry, it was in connection with Jabozuma's posts about oil and 4,000 rpm.

 

Incidentally, is revving to 6,500 with an oil temperature of 81ºC entirely wise? Genuine question, I would have thought that the normal operating oil temperature would be higher?.

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Entirely wise as far as i am concerned to get the Oil up to near Operating Temperature before Sprinting.

I got it to 80*oC indicate first. (the cars Indicated Temp is not quite accurate.)

It is at around 90*oC before being used in anger.

(But remember i am not saying do as i do, and i am not saying put in 3.7 Litres as i do.)

 

Because once you start going for it, its going to be getting lots hotter.

But i still try to get it cool again. & the 1.4tsi is very efficient at cooling the oil.

But then you use the correct oil for what you are doing, & good Coolant

& good high Octane Fuel & good Spark Plugs.

 

Once you get around to driving a 1.4 TSI if you ever do, you will get to know about the Oil & RPM's,

rather than just reading about them.

In cooler weather like during winter, much cooler than the 15*0c Ambient in the Picture,

you can travel 100's of miles and the Oils indicated Temperature might never show as high as 90*0C.

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Cool! What is your take then on twinchargers thirst for oil?

It looks like I'm about to find out. For whatever reason, I've been asked to pick my car up for an oil consumption test. I questioned the action on the phone as I don't have high oil consumption. It's going to take me a while to clock up 600 miles, maybe my engine will fail in that time?

I think they're using it to test the piston rings.

Seeing as it's not apparent on every vehicle there must be a variable to determine which engines suffer. It could be tolerance or a rushed bench test/run in. I suspect it's something to do with the ring/bore contact but I really wouldn't begin to have a clue without ripping one apart.

Edited by MattGreen
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It looks like I'm about to find out. For whatever reason, I've been asked to pick my car up for an oil consumption test. I questioned the action on the phone as I don't have high oil consumption. It's going to take me a while to clock up 600 miles, maybe my engine will fail in that time?

I think they're using it to test the piston rings.

Seeing as it's not apparent on every vehicle there must be a variable to determine which engines suffer. It could be tolerance or a rushed bench test/run in. I suspect it's something to do with the ring/bore contact but I really wouldn't begin to have a clue without ripping one apart.

 

Matt, I am glad I am not the only mad one! I wanted to ask you first without prompting :D

Shortly after I bought my vRS in Nov 2012 and got scared feckless reading the forums (thanks Briskie ;) ) I started researching the subject.

The first thing I came up with was block casting tolerances screwed up. This is the design (cannot remember the name) where cylinders are not connected with the rest of the block and held up by the head or something like that. It's been a while and I cannot be bothered to dig it out again, VAG brochures have it somewhere.

They use grey iron to cast the block, then they insert cylinder sleeves. Problem is, if the cast is not perfect then ther will be gaps between liners and the cylinders casts. This in time will deform the liners and no amount of pokery-jiggery with rings, crank vent pipes or anything else will cure it. Unless this is a small distortion and good liners scrub and hard new rings bedded well can cope with. This is then consistent with other problems some twinchargers exhibit. Improper mating between bore walls and rings introduces vacuum leak into the combustion chamber distorting the picture ECU is seeing, Lambda will be reading leanpotentially leading to overfuelling, coked plugs, which fail etc, etc. What also got me thinking was the a photo of plugs where 2&3 were substantially more coked and damaged than 1&4 and if you look at exhaust mani, which is very short anyway, you will see that pots 2&3 have shorter runners than 1&4 exacerbating the whole issue even further. 

Let me know what you think?

 

P.S. Before thread purity police descents the above IS relevant to the issue at hand :)

 

P.S.S. As for ripping one apart, if it wasn't my daily ride and dad's taxi I'd ripped her apart long time ago :D  :devil: . Take head off, bottom out and do a simple leak test with low surface tension fluid - will show straight away which pot is the culprit.

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I've not looked into it at all I confess, too busy. It seems like you've painted a good picture. If you're right I wonder if the cthe "cure" is thicker walled liners which will retain their shape better?

It's my thread, you crack on mate.

With regards to my car I'm worried that I will pass the consumption test and progress on my issue will stall. Its not much of an oil burner, it's just misfiring. I will say though that it does smell like it's running rich.

The service manager told me that the problem wasn't that bad. It only happens when it's cold and that it's fine when warm. I can agree to a certain extent, but my response was that it felt that I was driving a ticking bomb, a problem waiting to happen. Not happy at all its fair to say.

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They do run rich in general. I was watching fuel trims today on to and back from work. LTFT was always within limits but mostly getting into positive values due to short term reading up to -7% at times. Also, most of the time it was staying negative so lambda reading rich. I'd need pull full log to trace it more precisely but I think that is the picture. I cannot be botjered to pull the plugs out-maybe at Blyton Park in August somebody will have the tool for the job :). Have you pulled your plugs to have a look?

Sent from my GT-I9505 using Tapatalk

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They were changed for new at my last visit, along with the oil for a consumption test. Photos of the plugs were sent to SUK.

I don't have a coil tool...yet.

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So, I cleaned my tailpipes (ahem) as soon as I got home from the garage. I'm 100 miles into my oil consumption test and the pipes are shooting up already.

Also does my oil level look a little high or is it just me?

20140625_125419.jpg

Edited by MattGreen
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The Tail Pipes sooting up is not unusual or an issue with many very good running cars.

They run quite rich until the Engine/Oil is up to temperature.

................................

What is that on the Dipstick,   A stone cold dip

or a Hot Dip after the Oil is up to temperature (at least 80 *oC indicated) and stopped for a few minutes.?

 

If it is on the smooth bit above the Crosshatch when hot, it is OK.

Not Overfilled.

 

If it is up to the bottom of the top Orange Plastic when Stone Cold and unstarted, it is OK.

 

......................................

I do my checks cold & also with  the 'Zabozuma Check' before tarting a journey.

& sometimes confirm that at the end of a journey after stopping.

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Cold dip, well the cars been off since 8:30 this morning.

I'm not expecting it to fail on oil consumption. It's not too bad.

Thanks for the reply.

So far as I can tell the oil reaches the top of the top orange blob.

Edited by MattGreen
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??? Where are you at now.

 

You know for certain that you have a ECU Update done ??

 

Do you have 4 new matching Spark Plugs in the Engine?

Or is it One Plug only that was replaced?

 

??

Is the car starting Smoothly now,   at 1,100 rpm dropping to 800 in 40 seconds or so,

then running smoothly?

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So I currently have 4 new sparkies, and the ecu update.

The problem is unchanged, and Skoda uk think the compression is slightly lower than they'd like hence (I think) the oil consumption test.

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You see, one think I really cannot get here is crap "Skoda THINK it is slightly lower compression"- what a load of crap that is! Each cylinder will different readings when compression tested, key is are they above the lower acceptable limit? Nothing easier than to check, what is it to think about?!? Missfires ave all sort of sources and it should not tale more than two hours to diagnose it 100%. You have lean misfires and more rarely rich misfires (stuck injector for example) It could be due to vacuum leak on the inlet manifold, lack of spark, injectir signalling (ground) failure, injector voltage failure (cable snipped), or faulty injector. First check your fuel trims. Then stick a gas probe in your tail pipes and check HC and CO2 levels to see if rich or lean misfire. Then investigate the ignition system (plug sparking nicely?) and then your injector. While you jave plug out stick bore scope in to check the state of valves and piston crown.

Indolence really annoys me, especially whwn shamelessly sported by so called master technicians...

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This was Evil Miyagi's vRS after the tip broke off the spark plug.

 

Like so many others ended up, after Skoda Technicians were stumped at what was wrong with cars,

and others say, ' that drives perfectly normal. it feels just as it should.'

or

'they all use oil, that is normal.'

 

My favourite is the Skoda HQ Customer Services people that say.

'It is blown out of proportion on the internet'.  & 'Dont listen to people on Briskoda Forum'.

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What happened to yours?

 

Shall we say it went "bang"?

 

started off with serious oil consumption then misfires (lots of misfires)

 

Then 5 sets of spark plugs after 4 breakdowns in one day (yes 4 separate calls to Skoda assist in 24 hours) and many on separate occasions over 6 months...  The worst of which was having an RAC van outside the breakdown company I work at :o

 

then finally following a missing tip, cylinder three went bang :/

 

EM

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  • 2 weeks later...

J a b o z u m a had the dipstick smelling of petrol then had a professional oil analysis. He can tell you the story.

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Yes, mine was so bad I called my dealership and said I will not drive the car as it was "making oil"!! Nice oldboy in RAC van arrived. Had a look, smelled it, took a lighter to my car's dipstick, which did not come up in wooshing flames and concluded all was peachy lol - what a tool!

I dropped the oil myself, sent it to a lab and never had any more "making oil" issues.

Sadly the lab, and most labs in the land, did not do fuel content test so I was no wiser. What I learned was that I need to change my air filter as too much silica was present in my oil - where I work part of the road is gravel, kills air filters, gets to engine oil and screws up bore walls.

4W30 Castrol simply does not stand up to very rich running at high revs (prone to fuel dilution) and doesn't have high enough temp and shear rating to cope. It turns to water at high temps and gets diluted with fuel amd engine starts to burn it, not mentik compression loss due to blow by causig misfires, crapped up plugs, burnt valves and destroyed piston crowns. Another thing I began suspecting recently was flawed (due to space constraints) exhaust manifold design. Two middle runners are sunstantialy shorter that the puter ones. Plugs 2&3 I've seen on here were substantially more fouled and crusted than 1&2 potentially suggesting exhaust gas backing up into combustion chamber due to pressure wave deflecting from the end of shorter runners. LOBA has good manifold but proved troublesome-misfires. This time map was not adjusted to make it work-just theorising here of course!

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