Blue smoke issue

[brynden29]

Hey guys,
I searched all around and found some great help on this issue. Here is the deal. I bought a 1991 GSX with 90,000 miles on it. It is stock. Everything looked good. The stock exhaust had a hole in it so I used that as an excuse to get a new cat back and dp. So I threw it all on and took it for a drive. I noticed that under WOT the boost was about 15 pounds. It pulled great, no worries. Well the next day I am letting it warm up in my driveway and I see some smoke. It looks like blue smoke. Not a lot, but enough to get my attention,

So for the last few days I notice that it does not appear to smoke when I am driving or boosting. Only when I come to a stop and let it sit for a little while. And it is not all the time either. It seems to do it for sure if I build any boost.

So I did all the things this site recommends. I checked the LICP and it did not have very much oil residue. I checked the turbo, no shaft play at all. I checked the PCV valve and it is working. (could only blow through one side) And I did a compression check, here are the numbers:

Dry: 155, 155, 160, 151
Wet: 180, 180, 184, 175

So what do you think? I am not sure what to check next. I don't really like smoking so I would like to fix this. Can the valve cover have anything to do with this? It looks like the previous owner did not use a gasket, just some sealant. Just a thought.

Sorry so long guys, just want to give you all the facts. My mods are BR UICP, Megan 2.5" DP, BR 2.5" Exhaust, Nology Wires, TurboXS MBC

 

[diablos991]

The fact that it is smoking after idling leads me to believe that your valve stem seals are leaking. To confirm this, take off the exhaust manifold and check for oil in the exhaust runners and on the valves themselves.

The fact that the wet test made your compression jump leads me to believe that your rings are worn.

You could get a leakdown test performed to pinpoint the loss in compression. (Rings, Head gasket, valve seats, or valves)

 

[zilo900]

^^ check out that stuff first, unless you just wanna jump into a new turbo anyway. But when my turbo was blown, I had blue smoke come out when i boosted and not just a little, a LOT, it got worse after driving it more. I had no oil or anything in the ic pipes, but changed turbos and no more smoke.

 

[brynden29]

Thanks for the help. I have noticed that it seems to smoke worse with the AC on.

I don't think it is the turbo because it does not seem to smoke when boosting or driving, only at idle. Unless it is smoking while I am driving and I just can't tell.

I will definately check out the exhaust manifold, I need to pull it to install my egt probe anyways.

 

[JoJoTSI]

noneofthe above

 

[kelvinb]

i had a blue smoke issue on decel, turned out to be a previous detonation issue (ringlands were cracked on 4)

 

[brynden29]

Latest Update:

Last night I pulled the manifold off. I did not see any oil in the runners. They were all charcoal looking black. I reached in and ran my finger over the valve stems and only 1 had a little bit of oil on it. The old manifold gasket had oil all over it and some of the manifold studs had oil on them. I might be leaning toward the turbo, but I am really not sure, what do you think?

Also, I noticed that sometimes the smoke appears to be more whitish than blueish. I know that the turbo uses oil and coolant, but can the coolant be leaking into the exhaust? I am kind of at a loss. Any ideas?

 

[diablos991]

Oil dumped into the exhaust system may make a whitish/gray smoke.
If anybody doesn't beleive me, put a spoonfull of oil onto your exhaust manifold while its hot.

Try unbolting your DP and checking the o2 housing and the exhaust side of the turbo for oil.

When my t25 went out, I had whitish smoke coming out of the exhaust between shifts and upon heavy acceleration.


EDIT: Did you ever perform a compression test to find out where you are losing compression?

 

[fourreGsixty3]

Blue smoke on accel, means either your rings are gone, or the seals in your turbo are shot. White on accel means head gasket or turbo seals. Go to this>>>http://www.dsmgrrrl.com/FAQs/compression.htm, and do the comp. test, then do the wet test.

Dustin

 

[diablos991]

Blue smoke on accel, means either your rings are gone, or the seals in your turbo are shot. White on accel means head gasket or turbo seals. Go to this>>>http://www.dsmgrrrl.com/FAQs/compression.htm, and do the comp. test, then do the wet test.

Dustin

I had white smoke on acceleration and it was my turbo. I would go more by the smell of the smoke than anything.

If you read the 1st post, you will see that the dry and wet tests have already been performed.

 

[fourreGsixty3]

Oh nice call on the dry and wet tests being done already, my bad. With that big of difference from dry to wet, my bet is on the rings.

Dustin