So, Ive got a '96 NG900, I just changed the turbo with a newly rebuilt unit from Chadwick, My old one had 140k and was putting out alot of smoke.
I immediately noticed an improvement with the new turbo and didn't notice any more smoke from my exhaust. Fast forward to about 1500 miles later...
I've been doing alot of highway driving in and out of traffic.
Sometimes when I slow down to a stop in traffic I notice blue smoke pouring out of my exhaust at idle speed; sometimes its there and sometimes its not. Revving it a little bit will make more pour out but then after moving in traffic for a minute or two it will be gone. I noticed this about 4 or 5 times when I was in stop and go traffic for about 5hrs today. When doing WOT pulls the car pulls nice and I don't notice any smoke during or shortly after when slowing down after the pull....seems the smoke is only occuring when the engine is under vacuum
I've modified the PCV system a bit just to rule that out as a possible cause, I've unhooked the large metal pipe that vents fumes from the valve cover to the turbo intake and attached a temporary small air filter right on the valve cover fitting, I've unhooked the PCV valve from the TB, (Putting a cap over the TB nipple) and just let the small hose dump out under the car. I figure this would eliminate any possible PCV problem that could cause smoke/oil being brought back to the intake?
My only idea is that is it possible my intake/intercooler piping and exhaust (3" DP with Saabsport) has so much oil residue from the old turbo that it is deciding to burn off even 1500miles later?
Any suggestions are appreciated,