Blue smoke - but what could cause it?

fubar andy

Moderator & N/W Rep
Staff member
Right well I've done a compression test and all are 140-145 cold and 130-135 hot.

An inspection inside the chambers 2nd 3rd and 4th (cold) they "looked" oil filled, however after the "blast out" the the pistons have cleaned up and the smoke has reduced some what, but it is still noticeable. (plugs look good too)

I also cleaned up the intercooler pipes and ancillaries before I went out for a drive. After my return from the "blast out" they have a small amount of oil (film) around the pipe, but that could be down to what has been left over from when I was out previous/the oil residue that's been left in there.

At the moment, I still think it was the turbo seals and perhaps they've sorted out the problem when they took it apart?

However I've still got the boost problems. The symptoms are still the same: when introducing the power slowly the boost sometimes hits 0.8 bar, mainly 1.1bar and when I change gear at speed and immediately apply the power (foot the floor) the boost gauge shoots (peaks) still around 1.3 / 1.4 bar and then falls back to 1.1 bar???

Looking at the actuator, it seems like its not moved at all before it went away? How do you "check" of the actuator is working correctly?
 

MarkTurbo

Well-Known Member
Looking at the actuator, it seems like its not moved at all before it went away? How do you "check" of the actuator is working correctly? [/FONT]
Take the actuator rod off the wastegate arm and check the preload, if you need to pull the rod out of the actuator more than half the width of the hole it could have too much preload causing your excess boost problem.
 

Tim

New Member
Attach the actuator to an air line and pass in 0.75bar to it and it should open up, that's how we tested mine. It turned out to be the rubber diaphragm in mine that had split due to exhaust gasses getting in there.

You could unclip the actuator arm from the waste gate and check that the waste gate opens freely.

Whenever i've taken intercooler / boost pipes off there is always a certain amount of oil in there, I assume that the turbo seals are slowly on their way out on mine then. No smoke as far as i'm aware though, good luck with it.
 

fubar andy

Moderator & N/W Rep
Staff member
Cheers for the info chaps. :thumb:

Just to add about tonight's activities, I warmed the car up before going for a run. Once the engine and all the gauges were ready I dropped at cog and pressed the loud pedal.

Only to find the boost rocket to 2 BAR+!!!! :shock: :?

Yes it quite literary it was unlimited boost! :?

Not sure what's going on here, but I stopped immediately and after a quick inspection I had a gentle drive home (tried the pedal again - hitting 1.5 bar *it would have gone higher*) I've put it back in the garage and will have a look at it tomorrow?

Still think is the actuator that's gone tits up?
 

PobodY

Moderators
Staff member
You've got less than a fortnight to get it fixed! - If you're getting unlimited boost, then there must be an issue with the wastegate control; if you're confident that it's not your actuator, then it has to be further up the line; solenoid or source?
 

Tim

New Member
- Check the vacuum hoses from plenum to actuator
- Bypass solenoid

If you still have unlimited boost then there is a problem with the actuator or wastegate
 
P

pulsarboby

Guest
wont be the wastegate unless its jammed shut
but as tim said
check all the vacuum connections from plenum and any boost control devices
my guess is that its your actuator is faulty
 

Tim

New Member
My bet is that it's a vacuum hose that is disconnected between actuator and plenum..

What do we win?
 

fubar andy

Moderator & N/W Rep
Staff member
Ok, I had a look around but couldn't really see anything out of place or pipes hanging loose/disconnected. However on closer inspection a lot of the existing pipes were badly corroded or looking like they were on their last legs.

So a quick pop down to the local motorsport shop and I've changed all the existing pipes with brand new ones.

A quick trip out and now its boosting at a steady 0.6bar.

So it looks like over time the pipes have just got worse and worse and now they are replaced now the system seems to be boosting back to it normal set-up.

Smoke from the rear of the car has reduced a bit more, there are some puffs of blue smoke from the rear exhaust when driven hard/rev'd to death, but it is a lot less that previous.

My guess is that the turbo company just repaired what was wrong with it and gave it me back without mentioning their possible repairs (for them it might be about keeping a clean sheet with regards to rebuilt turbo's that have come back faulty after they've tinkered with it?).

Either way I still need to have a bash about yet and see whether the smoke gets worse or goes away.

Out of interest what is standard boost on a GTiR, is it 0.6 or 0.7bar?
 

Tim

New Member
I THINK the actuator is rated at 7psi and then the standard solenoid bleeds 3 psi to hit the 10psi as standard? But don't quote me on that..
 
I THINK the actuator is rated at 7psi and then the standard solenoid bleeds 3 psi to hit the 10psi as standard? But don't quote me on that..
I agree chap. When engine is cold it boosts to 0.5bar (standard actuator spring rate) and once warmed up the solanoid bleeds off 0.2bar to give 0.7bar standard boost.... or 10PSI.
 
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