Carbon Build-Up

[neckarsulm]

Interesting, so maybe the MOT emissions test can be used to see how much carbon there is?

[lengster1]

Was it an mot test at audi dealership it failed? Wish id taken the offer of paying £50 and have £750 worth of cover if it fails next year!! Mind you that wouldnt even get the heads off would it at nearly £1k a day for a car mechanic!!!! Pad125 what are the dealers saying regarding this? I would think the failure of emmissions is more likely down to horrendous build up levels and valves not seating.

[neckarsulm]

Think it's time for another Italian tune up

[pad125]

Was it an mot test at audi dealership it failed? Wish id taken the offer of paying £50 and have £750 worth of cover if it fails next year!! Mind you that wouldnt even get the heads off would it at nearly £1k a day for a car mechanic!!!! Pad125 what are the dealers saying regarding this? I would think the failure of emmissions is more likely down to horrendous build up levels and valves not seating.

Well, the dealer was on my side to the point they contributed 3 times the cost that Audi did but then I have bought 7 Audi's from them in the last 6 years so I guess they were protecting their investment, pity Audi didn't think the same.

In retrospect, I guess it’s a problem we’re all going to have face up to as the product of DI. All the benefits of performance etc etc against the potential of having a top end strip. The total cost was £3k by the way, and yes the MOT was at an Audi dealer and MOT insurance thing wouldn’t have helped as there needs to be a component failure, I did try the ‘emission system’ angle as a failure but that fell on deaf ears as you might expect.

Has it tarnished the experience? well I guess it has. Its still an amazing car and yes I would buy another car from the dealer but I guess the most disappointment has to fall at the door of Audi UK or rather Audi AG. As Caldy has stated, they see this as a bi-product of DI for which we all bought into when we bought our cars and it appears their response is ‘deal with it’.

What I don’t want to happen is people reading this forum to be put off by this, yes it may seam like a terrible failure but the driving experience of the car is still outstanding. I think I was probably at risk more that others as I live and drive around London nearly every day and as everyone will tell you (especially the cyclists) is the average speed of traffic in London is 8mph!

Overall, my impressions of Audi as a company has deteriorated immensely. I would have thought that a company that has such an infrastructure would have the balls to deal with this in way that would want me to buy from them again. Sadly I think they will have to pull an extraordinary rabbit out of an amazing hat gain my confidence again.

[lengster1]

Very nice too hear that your dealer was very loyal in return for your longstanding custom,they maybe didnt have to go that far but the fact they did is very refreshing to hear.They deserve the thumbs up for sure! My theory is backed up a little by your individual case (town cars suffering more)

[pad125]

Very nice too hear that your dealer was very loyal in return for your longstanding custom,they maybe didnt have to go that far but the fact they did is very refreshing to hear.They deserve the thumbs up for sure! My theory is backed up a little by your individual case (town cars suffering more)

Yes on all accounts Lengster1, Walton Audi deserve a mention for standing up and being counted. I'm sure the constant town driving doesn’t do the motor any good but won't hear Audi admit that as it would imply the car isn't capable of 'all conditions' driving. It really needs the arse ripping out of it on regular intervals but I’m guessing that wouldn’t stand up in court when you’re fighting to keep your licence

[lengster1]

Fantastic summary ....PMSL

[neckarsulm]

Same carbon thing happens with EGR valves on TDIs only they are a lot easier to de-gunk!

[ArthurPE]

not so wild

I believe it is valve seal leekage, and some from the rings, which becomes much less when hot and tolerances shrink

I also think a good bit is unburnt fuel during warm-up
EGR and cold surfaces that cause condensing on the valves, cylinders, etc.

I totally disagree that the effects are barely noticeable. My engine was so badly choked up that one of the cylinders was down on compression due to a valve not able to seat properly due to deposits. No one can tell me that isn't affecting power because it quite simply is. End of.

A more accurate statement may be that the effects of carbon on a normally operating engine are barely noticable. Given it was significantly noticable in one cylinder on your car Karl that would perhaps lead to conclude there was a faulty part in that cylinder.

There is 'data' out there for all to see that has dismissed most of the areas from which people believe CB is attributable to. Poorly designed cyclonic separators; put a catch can instead and oil barefly enough to cover your thumb tip is collected at most. Valve overlap; there is data to suggest this isn't the case.

Perhaps a lot has to do with valve seals and the amount of oil that seaps through them in warm up phase. If they have a lot of tolerance in them when cold seapage may be higher than at operating temperature. This oil that seap collects on the valves and in the IM but if at low speed or stop start motoring / communting not enough airflow gets into the engine to blow this off towards the cyclonic separator. Combine this with lots of high revving early in the warm up phase which may push more oil through the valve seals before the shore up so to speak with heat in them the higher amount of oil present may accelerate the level of CB in the IM.

Just a wild theory of mine based very loosely along the lines of F1 technology. If you consider an F1 engine has to be pre heated and the oil warm and passed through before turning over because there is such tight tolerances to achieve the 18,000+ rpm they can run to. Ours are high revving but have to have low tolerances for cold start purposes maybe this is when the most amount of oil gets into the IM?

[ArthurPE]

Patrick, yours is the first emission failure I've heard of
I think Audi was wrong in not settling the matter more fairly and timely...
if it can't pass MOT, it's not serviceable for the purpose for which it was purchased...they broke the 'contract'
cleaning is not routine maintenance

having said that, something else caused the excessive deposits, they are not normal...
BUT, even then your car seems to be the same power as P_G's, both before and after...

and since ALL cars have deposits to one degree or another, and all except for a few (one so far?) pass emissions, the conclusion can be drawn that deposits don't cause the MOT failure and something else was at play, perhaps the same failure that caused the abnormal deposits in the first place?

[scaghead]

Very nice too hear that your dealer was very loyal in return for your longstanding custom,they maybe didnt have to go that far but the fact they did is very refreshing to hear.They deserve the thumbs up for sure! My theory is backed up a little by your individual case (town cars suffering more)

Yes on all accounts Lengster1, Walton Audi deserve a mention for standing up and being counted. I'm sure the constant town driving doesn’t do the motor any good but won't hear Audi admit that as it would imply the car isn't capable of 'all conditions' driving. It really needs the arse ripping out of it on regular intervals but I’m guessing that wouldn’t stand up in court when you’re fighting to keep your licence

i have to agree with you pat, the around town driving just does not suit these cars ... as neckersulm says a good italian tune up is a good medicine

[pad125]

I too believe that Audi have made a ricket here (sorry Arthur English term for f%$k up). They must know that there will be an amount of cars that will be driven in the circumstances that I encounter and will fail the emissions test due to the environment they are used in. I’m not really bothered about CB to be honest, what I need is a backup system that catches me when the system fails. I’ve bought Audi’s in the past for the reliability and when that fails I kinda hoped loyalty would catch me before I hit the ground. To me that has failed, I know we are in the middle of the worst recession in living memory but I’m sure if I treated my customers the same I wouldn’t be left without a pot to piss in!!!!!! I don’t think for a minute that other manufactures are treating their customers any different but if Audi want to stop a migration then they need to buck the trend

[RS6chris!]

Well..i must admit ive been out the last couple of days and give the car a damn good thrashing or "italian tune up" as some call it!!!

Burnt of a full tank of optimax with prolonged periods of high revs etc etc. Car ticking and cooling down like a gud un on both occasions....

She certainly feels a lot more responsive today and the rear of the car is peppered with small black chunks?? Carbon??

I agree these engines need a good blast now and then....

Just think of the amount of cars out there that are ownd by "non enthuisasts" who maybe dont drive the car like they stole it?? The potential is for a lot of cars to be well choked up!!

Maybe i,m kidding myslf but my car certainly is as quick as it ever was and i cant believe my valves although choked up can be anywhere as bad as that photo.


Keep giving it a good flog now and then thats my way of dealing wieth it.

[sonny]

the rear of the car is peppered with small black chunks?? Carbon??

.

Its normal to see the mix of vapour and carbon deposits this time of the year, as the condensation build up in the exhaust overnight. Nothing to worry about.

[scaghead]

rs4414, i had the same thing when i took mine out last week..[the soot peebledashed effect on the rear of the motor]... but as sonny said usually nothing to worry about..