Starting to smoke..

[Supra_dan]

Alright ladies and gents, I have an interesting issue going on.

Every now and then my car would smoke a lil bit, but lately I have noticed it a lot more.

Now, it is a very light color smoke (sometimes very light blue, but smells like burning oil, so i'm going to assume oil.

Okay so heres the symptoms. No smoke on start-up. No smoke on acceleration. Only smokes when car is fully warmed up and coming to a stop. for instance, I will be coming to a red light or stop sign, so I will cost in gear for a lil, then when I put it in neutral, it will then smoke for about 2-3 seconds, pretty good amount of smoke too.

So again, nothing on acceleration, hard or normal.

It's only when revving down you can say. While it mostly happens when I put the clutch in coming to a stop, it sometimes happens when I'm just costing slowing down, again when the revs are dropping.

All new and tight sealed pcv hoses (factory set-up, no catch can)
Also new valve stem gaskets (don't think it's those anyways due to it not always smoking)

So the basics: No smoke on start-up or accel. but only when coming to a stop and put the clutch in, or sometimes when just slowing down.



What in the world could it be?

 

[bad88mk3]

It could be coming from the turbo i would pull the turbo elbow off and check for oil residue.

 

[Supra_dan]

Ah thank you! I had forgot to mention that in my earlier post. But someone else has actually mentioned the exact same thing you said.

So that's two people so far that think it's the turbo.

Now i'm just at a loss though. What is it, the seals or whatever? And what would make it smoke only on decel?

 

[emmkaytree]

Here are some possible causes, some probable, some rare. Turbo seals if boosted, valve stem seals or guide, crack in the head or cylinder wall allowing oil in, weak ring(s), im probably missing some tell-tale stuff but theres some stuff thrown out there. More than likely it's a valve problem, pcv, or turbo seal.

Hopefully it is oil, my MK3 had those symptoms right before the head gasket went out..

 

[seoul4korea]

^^^ he pretty much nailed it

 

[Trent]

Valve stem seals will usually show their failure at startup since some oil has leaked through and burns off at startup. That's not to say that they don't have other symptoms, but that is one of the main ways you can always tell if its those seals.

Smoke only on decceleration or at idle screams turbo seals. I've had my fair share of blown turbos and have had this exact issue a number of times. Didn't smoke when boosted or during normal driving, but when coasting or idling, it would smoke. Only a little at first and then as the seals got worse, it would do it more and more.

 

[Supra_dan]

Thank you for the info guys.

I am inclined to think turbo as well, being that while granted nothing is impossible in this case, it seems all the other options are ruled out.


But I am not wrapping my head around the 'physics' of it I guess you can say.

What is it that it can smoke on decel or idle a bit but not on accel or start-up?

 

[bluepearl]

Absolute first step before any guessing: Compression test and leak down test.

 

[Beals]

smoke like that out the exhaust is usually turbo troubles though, bhg would have a coolant smell to it.

 

[Supra_dan]

I am going to tackle this issue shortly, been very swamped with work. However, if it is the turbo I will be very very upset. It's only got 16,000 miles on the rebuild, never boosted over 9 pounds..

 

[Beals]

old turbo's don't always rebuild well and it depends who did them how well the quality of it was done. but 16,000 miles is alot better then my buddy who made less then 1000km before his 57-1 failed.

 

[Supra_dan]

It was rebuilt from a reputable member on this forum.

But I guess my mileage on it is just fantastic in comparison to your friend..

 

[Drake69]

I had the same thing happen with my car. Pulled the intercooler pipes and downpipe to the turbo, oil on both sides. A 57trim DM turbo later and the problem stopped.

My vote as well.

 

[Supra_dan]

Hmm..

Well shit. Ain't this just grand, I shoulda opted for the Sp turbo. Waterless ball bearing instead of this one

 

[Beals]

ball-bearing turbos definately have the longevity factor compared to other turbos. I have rebuilds for my c12a's myself but I figured by the time I blow them I will be looking to upgrade.