Oil smoke worry

Hi all, I have a jspec tt 6sp,i have noticed oil smoke on the odd occasion over the last few weeks.I have just fitted an electronic boost controller,blitz nur spec r,2nd decat pipe and trl fuel cut.I am running it at about 1.2 bar max.I am unsure if i have a turbo oil problem or if it is valve stem seals.I notice the smoke mostly when the engine is up to temperature after about 10 miles and is most noticable when coasting in gear then reapplying power.Also noticed it when idling and then pulling away smoothly.No smoke when power is sustained.Mileage on the car 68500.No smoke when driving hard.Anyones ideas....Cheers

[alex h]

(Fakenham, Norfolk?)

Quite honestly it could be both but I would err towards the valve stems as it does happen when idling. And it's not always apparent at full throttle. Couldn't just be an overfill of oil could it? Have you checked the oil level? These sorts of faults are hard to diagnose on the internet though.

[Chris Wilson]

removing back pressure from the exhaust will often send a weak turbo seal "over the edge", the pressure diferential across the seal increases and oil leaks into the turbine housing. Sounds like tiring turbos to me.

[Martin F]

HI & Welcome

What you have described there in quite a bit of detail are classic symptoms of the turbo oil seals failing http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/sad.gif

Sorry to be the bearer of bad news, but its fairly conclusive from the way you have described it. If it was valve stem seals it would be very smokey at start up and then be fine generally apart from when pulling away from sitting idling for a long time.

Another thing that may be worth doing is to pull of the turbo hose going into the wing and see if there is a lot of oil in it. If there is, then its 100% turbo oil seals.

[Martin F]

Removing the CAT has probably made the symptoms more noticeable.

Thanks for advice,If thers is no oil in the intercooler pipes,then does this mean that oil is possibly leaking into the exhaust side of the turbo,i removed the intercooler hose 2 days ago to check and it was very clean.

[Martin F]

Quote[/b] (jonna @ July 23 2004,22:39)]Thanks for advice,If thers is no oil in the intercooler pipes,then does this mean that oil is possibly leaking into the exhaust side of the turbo,i removed the intercooler hose 2 days ago to check and it was very clean.
Good point, forget my post, times getting on and i'm tired.

http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/down.gif

[Chris Wilson]

Quote[/b] (jonna @ July 23 2004,22:39)]Thanks for advice,If thers is no oil in the intercooler pipes,then does this mean that oil is possibly leaking into the exhaust side of the turbo,i removed the intercooler hose 2 days ago to check and it was very clean.
Yes, sounds like a leak into the turbine side. More common on UK turbos, but all of them wear out of course. try artificially restricting exhust (raise back pressure with old fashioned brass pan scrubs wired into the tailpipe, don't go mad, just add a bit of restriction), and try the car. If smoke stops it's the turbo seals.

[alex h]

Well I was hopelessly wrong then...I'll just sit at the back of the class

[Martin F]

Or blame it on tiredness like me http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/biggrin.gif

Alex H how did you know Fakenham Norfolk......