smoke when starting

5.0 V10 50v biturbo - 571 bhp
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c3nturi0n
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Posts: 467
Joined: Tue May 29, 2018 10:50 am

Re: smoke when starting

Post by c3nturi0n » Tue Feb 04, 2020 11:08 am

Mileage?

Is it a tuned car?
2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

Jim Haseltine
4th Gear
Posts: 895
Joined: Mon Jan 04, 2016 2:26 pm

Re: smoke when starting

Post by Jim Haseltine » Tue Feb 04, 2020 11:35 pm

Does the car still have the original turbos? Try removing the turbo-inter cooler hoses (with an oil catch tray under them) - if there's anything more than a little oil inside the hoses then you could be looking at a worn turbo. My car is a 2008 with similar miles and both turbos were leaking oil almost as fast as I could add it.

c3nturi0n
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Posts: 467
Joined: Tue May 29, 2018 10:50 am

Re: smoke when starting

Post by c3nturi0n » Wed Feb 05, 2020 11:18 am

Ogi's right... i'd suggest to check it all over by RS specialist. They are best placed to comment on issues that are beyond DIY knowledge and that doesn't come up as error on diagnostic tool/s.

Re latter, it may be worth scanning the car to check for error (but i doubt that oil leak will come up as positive).

Keep us posted how you get on.
2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

Ads50
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Joined: Sat Apr 27, 2019 7:06 am

Re: smoke when starting

Post by Ads50 » Wed Feb 05, 2020 2:16 pm

Do you cool the car down when u turn it off? Is it drinking oil? And does it smoke when u put your foot down?


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C_J
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Re: smoke when starting

Post by C_J » Thu Feb 06, 2020 9:01 pm

This sounds like a one way check valve failing or the pcv system.
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Jim Haseltine
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Re: smoke when starting

Post by Jim Haseltine » Thu Feb 06, 2020 11:09 pm

On my car 2 of the 3 non-return valves in the breather system had failed.

c3nturi0n
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Joined: Tue May 29, 2018 10:50 am

Re: smoke when starting

Post by c3nturi0n » Wed Feb 19, 2020 5:28 pm

Jim Haseltine wrote:
Thu Feb 06, 2020 11:09 pm
On my car 2 of the 3 non-return valves in the breather system had failed.
those under the air filter assembly Jim?
2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

Jim Haseltine
4th Gear
Posts: 895
Joined: Mon Jan 04, 2016 2:26 pm

Re: smoke when starting

Post by Jim Haseltine » Wed Feb 19, 2020 6:19 pm

Yep. The left and right Items 1 on https://nemigaparts.com/cat_spares/etka ... 41/103500/ the central one was ok. If replacing them take note of the flow direction arrow on the valve body.

c3nturi0n
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Posts: 467
Joined: Tue May 29, 2018 10:50 am

Re: smoke when starting

Post by c3nturi0n » Thu Feb 20, 2020 2:37 pm

Cheers Jim.

Easy to replace?


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2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

Jim Haseltine
4th Gear
Posts: 895
Joined: Mon Jan 04, 2016 2:26 pm

Re: smoke when starting

Post by Jim Haseltine » Thu Feb 20, 2020 4:06 pm

The one for the right bank (under the PCV unit) wasn't difficult, the one for the left bank was awkward and the centre one (which I removed to check) was almost impossible. The breather/vacuum pipe assembly which it fits to on my car was brittle (and not cheap) so take care.
I've got this nasty thought at the back of my mind that I might not have fitted the valves the right way around - I'm sure they're correct but to settle my mind I'll have to take a look at the weekend.
Last edited by Jim Haseltine on Thu Feb 20, 2020 11:44 pm, edited 1 time in total.

c3nturi0n
3rd Gear
Posts: 467
Joined: Tue May 29, 2018 10:50 am

Re: smoke when starting

Post by c3nturi0n » Thu Feb 20, 2020 4:58 pm

Cheers Jim.

Other than smoke on start up or while accelerating, any other symptoms that failed valve does?


Rgds


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2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

Jim Haseltine
4th Gear
Posts: 895
Joined: Mon Jan 04, 2016 2:26 pm

Re: smoke when starting

Post by Jim Haseltine » Fri Feb 21, 2020 12:05 am

Couldn't say, but I doubt that it's good for the oil breather system.
It's a balanced setup - at idle/light throttle there's lower pressure in the inlet manifold than in front of the turbos so the fumes that have got past the coarse and fine separators are sucked into the inlet manifold. When the throttle is open there's higher pressure in the manifold than in front of the turbos so the fumes are sucked into the front of the turbos. In both cases the fumes end up being burned in the cylinders, it's just the route they take to get there that varies. As both turbo non-return valves had failed on mine there would have been air being sucked from in front of the turbos directly to the inlet manifold - off the top of my head I'd expect that to result in the engine running a bit lean.

*All that is qualified by it being 11pm and I've downed a good half bottle of red so my logic might well be on it's head.....

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