Alright here's the deal I work for MAPerformance and we put my engine together a few weeks ago(Evo VIII):

-JE Pistons(out of a crankwalked 2g with hardly any miles on them, block was bored to these pistons)
-JE Piston Rings(Brand New)
-Cometic Head Gasket(Head Decked)
-Eagle Rods
-BC 280's
-BC Springs
-Supertech Valve Seals

I'm running AEM and we tuned it the other night and now after a pull it smokes hard core oil smoke on decel and only on decel. During the pull and during regular(no boost) driving there is no smoke. We don't think it's the turbo(stock) because there is no shaft play and why would it only smoke on decel.

Anyone have any ideas?

 

Compression test: Good across the board

 

You may have a oil land ring problem, or bad valve seal, or turbo seal. The reason for smoke on decel is vacuum.

Watch your plugs, and watch the turbo inlet for leaks. youll find it soon.

I would be suspect of the rebuild.

 

Rebuild was done by Kyle here at the shop. He's done a million motor builds along with making 709hp on his Talon and running a 9.

Thanks for the reply!

 

Also Plugs looked very clean. Not like plugs after burning oil...

 

Doesn't mean it isn't the rebuild, especially considering you didn't use new pistons...

Anyway, did you check the stem seals in the head? They pull oil into the combustion chamber when leaky and produce oil smoke on back-off.

 

sounds like a valve stem seal is leaking.

 

Hope it is and not piston rings.

 

Perform a leakdown test.
That will give you a pretty good start to where the problem lies.

 

Why would it be the valve stem if he checked the compression and its good for all cylinders? Sorry for the newb question, just trying to understand.

 

listen at the tail pipe or the intake.

looks like you are that person that shxt happens too. to bad, you got bad karma?

 

Like I know who that is.
Things happen, people make mistakes.

 

WHy do you think those pistons would have anything to do with this? If they were bad, there would be other symptoms other than just smoking on decel.

 

Evo 8 valve pockets are opposite of 2nd gen pistons, not sure if thats your problem but im sure it cant be helping.

 

when you check compression, the valves are closed, so a leaking stem seal won't show up. But under decel, the intake manifold and cylinder itself see vacuum, sucking oil past the valve stem seal if it's bad, and into the combustion chamber.