Blue smoke after coming off boost?

8bit · Sep 27, 2010

Beginning to worry that my turbo is developing a fault. For the past month or so I've had this strange whining sound, noticeable at low revs, particularly when starting the car from cold. The noise seems to rise and fall according the the engine note but lags slightly behind it.

Yesterday and today I've noticed that if I accelerate quickly using a bit of boost then come off to cruise once I've reached the speed limit, sometimes I see a bit of smoke in the rear view mirror, it comes a second or so after off-boost and lasts for a couple of seconds. Can't really tell what sort of colour it is but I'm slightly colour blind anyway. The inner part of the exhaust tip is pretty black but it's been a few weeks since I washed the car and don't think I remembered to clean the exhaust tip even then.

Last time I logged boost it seemed to be making requested boost OK. Can't hear if that noise is still there at higher revs over the induction noise and the normal turbo whistle, which sounds OK.

Should I be worried about my turbo, or am I just being paranoid cos I've had a few problems with the car recently? The car is going to the garage on Wednesday for some service type stuff, is it worth asking them to do a visual check on the turbo, i.e. will they be likely to spot obvious problems just having a quick look at it?

auq · Sep 28, 2010

mine has this issue only sometimes, ive recently de-catted so thought it may be something to do with that but cant see how, if its blue smoke then prob oil seals in your turbo gone, is it high mileage?, also the valve stem seals tend to go 'HARD' aswell in the higher mileage cars, hope you get it sorted mate

8bit · Sep 28, 2010

Mileage has just passed 50,000 so not really that high at all. Are turbo seals entirely internal? If so then I take it the turbo will have to come off and get sent away for reconditioning?

As I said the car is in the garage anyway tomorrow for some other stuff, any point asking them to do a visual inspection for cracks/excess oil in the inlet/outlet?

8bit · Sep 28, 2010

Bump - anyone else got anything to add to this?

leon cupra r · Sep 28, 2010

****.... Ive just seen this... with our cars having similar probs recently.....

I have noticed a funny noise from my car, again seems to be noisier when cold - you can hear it on tickover, coming from the air filter... yeah I suppose you could call it a whining sound..... carries on for two seconds after you turn the engine off and goes up in pitch as the engine stops....

does this ring any bells?

8bit · Sep 28, 2010

kinda, yeh, altho i haven't noticed the noise still there after switching off the engine. Mine usually quietens down after the car has warmed up a bit. I'm more concerned about the excess exhaust fumes after coming off boost.

As for the noise, I read somewhere that tired fuel pumps can be noisy, if it's still making the noise by the time I get to the garage in the morning I'll ask them if they have any ideas...

leon cupra r · Sep 28, 2010

Mine definately comes from the air filter.... hence why I was sort of worried my turbo may not be at it's best.. until the logs recently showing loads of boost... cant see it producing that much if it was dying!

edit: dont think mine is smoking tho, other than the usual white smoke of condensation that goes from now till spring!

8bit · Apr 7, 2011

Thread resurrection

Noticed this again this evening. Drove to mate's place after work, for a while I'd notice a bit of white exhaust fumes after coming off boost and changing up. This came a few seconds after coming off boost, not right away, and would last for a few seconds then disappear until next time I had to accelerate.

However, once I left my mates' place and came home, it wasn't doing this. Any ideas? Why would I sometimes get extra fumes a few seconds after coming off boost?

jamie1 · Apr 7, 2011

i would also say turbo seals are weeping slightly. i fitted a downpipe and decat not too long ago and experienced a puff off blue smoke as i pulled away heavy footed. the lack in back pressure can cause the seals to leak as the turbo is able to spool more freely. do you have a decat etc? sorry if i have missed you saying you have.

edit* if you notice smoke on over-run it would indicate stem seals.

t0m · Apr 7, 2011

Sounds like tubby seals.

8bit · Apr 7, 2011

jamie1 said:
i would also say turbo seals are weeping slightly. i fitted a downpipe and decat not too long ago and experienced a puff off blue smoke as i pulled away heavy footed. the lack in back pressure can cause the seals to leak as the turbo is able to spool more freely. do you have a decat etc? sorry if i have missed you saying you have.

No decat, just the standard exhaust still.

Weird thing was, after I'd popped in to my mates place it wasn't happening on the way back home. Nipped out to Sainsbury's later on too and it didn't happen then either.

So if it is turbo seals then can any decent garage fix that or is that looking like a trip to a turbo specialist like CR Turbos? Anything else I can do to work out for sure if it is turbo seals?

jamie1 said:
edit* if you notice smoke on over-run it would indicate stem seals.

Nah it wasn't on the overrun it was on steady throttle at a constant 40mph in 4th or 5th gear. A few seconds after changing from accelerating to constant speed I'd see a bit of exhaust gases for a few seconds. Hard to tell what colour it was, think it was white but if it was blue then it was a very, very pale blue.

Should also point out that I still have this strange, owl-like sound as described in the original post which seems to rise and fall with engine RPM, but lagging slightly behind it. Not sure if this is connected to the occasional excess exhaust fumes tho.

csd_19 · Apr 7, 2011

Possibly hot-side turbo oil seals, letting oil weep through slightly which is then burnt off. Shot turbo bearings sound like a police siren as it comes near boost (but not the usual turbo whistle sound)

8bit · Apr 7, 2011

csd_19 said:
Possibly hot-side turbo oil seals, letting oil weep through slightly which is then burnt off. Shot turbo bearings sound like a police siren as it comes near boost (but not the usual turbo whistle sound)

Can sometimes hear the noise at idle in neutral, like if I've just switched the car on. I think it's louder when the weather is colder too.

Just noticed over the last couple of days that sometimes it changes in pitch a bit on its' own even if engine RPM aren't changing, like at idle.

The turbo was making requested boost OK last time it was logged though, see below:

Code:

Saturday	5	February	2011	14:47:29:26499	VCDS Version: Release 10.6.3	Data version: 20101206									
1ML 906 032 A		1.8l R4/5VT         0002													
															
	Group A:	'001				Group B:	'115				Group C:	'020			
		RPM	Temperature	Lambda	Bin. Bits		RPM	Load	Absolute Pres.	Absolute Pres.		Idle Stabilization	Idle Stabilization	Idle Stabilization	Idle Stabilization
	TIME					TIME					TIME				
Marker	STAMP	 /min	°C	 %		STAMP	 /min	 %	 mbar	 mbar	STAMP	°KW	°KW	°KW	°KW
	0.31	1840	75	3.1	11101010	0.61	1920	92.5	1770	1190	0.02	0	0	0	0
	1.21	2000	75	0.8	11101000	1.52	2080	113.5	1890	1380	0.92	0	0	0	0
	2.12	2240	75	1.6	11101000	2.42	2360	138.3	1870	1680	1.81	0	0	0	0
	3.02	2520	75	7.8	11101000	3.33	2640	157.1	1790	1910	2.73	0	0	0	0
	3.93	2800	75	4.7	11101000	4.24	2920	154.1	1770	1820	3.63	0	0	0	0
	4.84	3120	75	5.5	11101000	5.14	3200	148.1	1770	1780	4.54	0	0	0	0
	5.74	3400	75	4.7	11101000	6.05	3480	151.9	1800	1790	5.44	0	0	0	0
	6.65	3680	75	3.1	11101000	6.95	3800	153.4	1790	1790	6.35	0	0	0	0
	7.56	3960	75	3.9	11101000	7.86	4040	151.1	1770	1790	7.25	0	0	0	0
	8.46	4240	75	4.7	11101000	8.76	4320	151.9	1780	1790	8.16	0	0	0	0
	9.36	4480	75	5.5	11101000	9.67	4560	146.6	1790	1800	9.06	0	0	0	0
	10.27	4720	75	3.9	11101000	10.57	4800	146.6	1780	1760	9.97	0	0	0	0
	11.18	4960	75	5.5	11101000	11.48	5040	148.9	1790	1790	10.87	0	0	0	0
	12.08	5200	75	4.7	11101000	12.38	5280	153.4	1830	1820	11.78	0	0	0	0
	13	5440	76	3.9	11101000	13.29	5480	153.4	1870	1820	12.68	0	0	0	0
	13.89	5640	76	4.7	11101000	14.2	5720	160.2	1890	1860	13.59	0	0	3	0
	14.8	5840	76	3.9	11101000	15.1	5920	153.4	1880	1910	14.5	0	0	3	0
	15.7	6040	76	1.6	11101000	16.01	6080	150.4	1840	1880	15.4	0	0	2.3	0
	16.62	6200	76	-9.4	11101000	16.92	6240	140.6	1800	1850	16.31	0	0	2.3	5.3
	17.51	6320	77	0	11100000	17.82	6360	132.3	1700	1750	17.22	0	3	7.5	8.3
	18.42	6440	76	0	11100000	18.72	6480	124.1	1620	1630	18.13	0	3	9	8.3

So if you're right enough then any idea where to get a recon'd K04 at a decent price? Or can the above be fixed by a regular garage?

JamJay · Apr 8, 2011

Just to throw something into the mix, what temp sender do you have...green or old black one? When these go I believe a side effect is running rich leading to coking up the exhaust in black soot. This won't fix your noise but I feel it was worth a mention just in case

.

8bit · Apr 8, 2011

JamJay said:
Just to throw something into the mix, what temp sender do you have...green or old black one? When these go I believe a side effect is running rich leading to coking up the exhaust in black soot. This won't fix your noise but I feel it was worth a mention just in case .

No idea, where would I find this? Wouldn't it throw fault codes if it was shot?

JamJay · Apr 8, 2011

Not necessarily, it's one of those things that only throws a fault when it's completely dead. Last time I went to an RR day they did tell me that mine was starting to go so I am replacing it this weekend.

It's located on the right side of the block as you look at it from under the bonnet, about half way down where all the coolant pipes run. I can't access pics her at work to show you. Maybe someone else can help here where the categories 'fun stuff' & 'anything remotely interesting' aren't banned

.

rsmith · Apr 8, 2011

You do release your CF's are stupid high at the top end, its knocking badly on the top end.

8bit · Apr 8, 2011

rsmith said:
You do release your CF's are stupid high at the top end, its knocking badly on the top end.

Yep, but a dying turbo is a bigger worry at the moment. Unless the two things are related somehow?

The coolant temp looks surprising too, the dial on the dash was showing dead on 90 (it always does once warmed up) but for the ECU to only see 75, would that support JamJay's theory on temp sensors/senders?

JamJay · Apr 8, 2011

That would suggest a temp sensor fault as it looks like the car is not getting up to proper temperature. I don't honestly know a lot about this but I have read that the side effects are hesitation, jerking, over fuelling and more soot in the exhaust leading to black tailpipes. How do you measure engine temp on vag-com?

8bit · Apr 8, 2011

JamJay said:
That would suggest a temp sensor fault as it looks like the car is not getting up to proper temperature. I don't honestly know a lot about this but I have read that the side effects are hesitation, jerking, over fuelling and more soot in the exhaust leading to black tailpipes. How do you measure engine temp on vag-com?

Not sure, I'll have a look on the Ross Tech site, but I do know that block 001 shows coolant temp, I wasn't aware there was a separate sensor for the engine?

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