Background: About 2 years ago, I just had the motor rebuilt with about 5-10k miles put on it. Was driving around one day and noticed large amounts of white smoke on deceleration. About a month later, I left the country and had the rx7 sit for awhile. I returned and got it to start up and it ran fine except it still had the smoking problem.

Its not coolant. It has an oily smell. The car smokes only on idle and only after warming up. It doesn't seem to smoke at deceleration anymore but when it does smoke at idle, it is significant. During driving, I am sure that is does not smoke since I've had people drive behind to see if it does. Also, it idles normally and doesn't have any hard starting. The oil doesn't seem to diminish much from the oil stick. Oil pressure is normal during idle and driving.

Now I came to the conclusion that the white smoke is either from a bad turbo or bad rings. My question is how would you check if the turbo would be bad. I already checked the inside of the intercooler piping and I had enough residue inside to make my finger black when I wiped it, although I did not see any actual dripping oil or collective oil in there. I am planning to later remove the turbo, but I am not quite sure what to be checking for. Also, I'm going to clean the piping well. What is the normal amount of residue for piping? Should it be clean or would having some slight dirt be normal? How would you check if the rings would be bad other than taking apart the motor?

 

Sounds like oil control rings to me, I've had similar symptoms a lot. Short of removing the turbo and checking the ports I don't know of an easy way to determine if it's turbo or the control rings.

 

sounds like the control rings. my new motor is doing this BAD i mean when i start it up in the morning it smokes so bad it burns my eyes and i have to take another shower because i can't get the smell off me. if the tops up and i start it i have open it up and open the doors becasue in the cabin its like you just did a burnout in a funny car or somthing. It's BAD. but O well, good oil pressure, amazing compression, just turn up the boost it will be fine

 

If it only smokes after warming up check your downpipe for oil. I bet you find it in the down pipe but not the turbo manifold.

 

You checked the intercooler piping,But you should also be checking the turbo Exit.
that involves popping the downpipe off to Look at the Turbo's exhaust Side.
I had a couple Bad turbos,So far,I bought used,.and I hadn't even Ran them!
One had Oil on the INLET..Not bad to run..sort of Lubes the internals,Minimal smoke.So far!
The other had Oil Residue on the Exhaust side.Upon Popping the Bolts off the rear plate and looking at the Wastegate flapper,I saw a Mini pool of black oil.
this one gave me smoke from the engine bay,and a bit of smoke out back.
I gave this Turbo to a Kid,who took it apart and told me the Seals are shot on it.

 

^^ agreed, probably turbo. Happened to me.