Carbon clean

[RIV]

I just took it out the garage today for a fiddle and put it back in when it started to rain, I can guarantee it'll be a bit smoky when I start it again. I usually make an excuse to take it out if I start it, not running it up to temperature must contribute to carbon build up.

Mine always did this from nearly new, if you just start it up to move a few feet then stop, when you start again you get a puff of smoke, I would say that's just normal for a b7. Nothing to worry about

[jaysrs4]

I just took it out the garage today for a fiddle and put it back in when it started to rain, I can guarantee it'll be a bit smoky when I start it again. I usually make an excuse to take it out if I start it, not running it up to temperature must contribute to carbon build up.

Mine always did this from nearly new, if you just start it up to move a few feet then stop, when you start again you get a puff of smoke, I would say that's just normal for a b7. Nothing to worry about

I'm inclined to agree. I've had valve stem oil seal issues on cars before and they also smoked on the overrun too. CVH motors being the worst!

[sakimano]

Based on the research and reading of the problem over the years, it's very common for a "significant" amount of coke to return within 1k miles.
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1k miles is a bit of a stretch, no? For example in the US two guys installing an APR supercharger on a car that was cleaned 5k miles ago said there was 'barely any' when they took the manifold off. They have seen dozens of cars photos and in person so they have a good idea what the various levels of carbon look like.

A slight coating, sure. But significant? As in causing a significant loss in power or causing a significant amount of blockage? I have seen nothing to support that

[adsgreen]

Just basing in what I've read in the past - I'm sure different cars used differently will coke at different rates. Maybe some had other underlying issues such as an undiagnosed oil separator fault? Who knows.
The key point is not the exact number when coking returns but that it does relatively quickly and the problem isn't terminal. It'll just plateau at a certain point.

[sckrs4]

What will happen if you don't do the carbon cleanup? Would the engine pack up around 100k miles?

The pictures look a real mess! Is this the entire Audi fsi range?

Shouldn't Audi spend a bit more on R&D to come up with a fix?

Has anyone approached Audi UK directly on this issue?

~

The engine won't pack up - the engine will just gradually go down on power/efficiency to a point that it will go into limp mode.
If your car has 100K on the clock and has never had a carbon clean I would strongly recommend that you get it done - the difference it makes is like night versus day - The usual suspects, MRC, AMD, Unit 20 & Revolution all offer a service to get it done in a day - around £500 - I consider it to be an annual service task

There is no fix for it - it's a design flaw with the FSI engines as there is no actual fuel flowing over the valves - It just seems to be that the 4.2 V8 suffers more from it

Not sure I agree with this. Based on the research and reading of the problem over the years, it's very common for a "significant" amount of coke to return within 1k miles.
Based on that if the problem wasn't self limiting then all engines would be dead within 20-30k miles but that's simply not the case.
I was says the crud builds up to a point then it isn't strong enough to cope with the airflow into the engine and small bits break up and are burnt off. it also explains why being a little hard on the engine with occasional full power runs does in fact reduce the problem if not eliminate it.
You can see this if you dyno a car that's been city driving a lot as you actually see sparks coming out of the exhaust as the revs build.

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Yes this makes sense. So in a nutshell, de-coke the engine at 70K would be good to have done, but not mandatory.