Hello I have a turbo d16z6 with cp pistons, eagle rods, arp head studs, dsm t25 turbo, dsm 450 injectors, stock head with new stem seals, h22 throttle body. I got my car tuned to pass emissions and run great. Recently I decided to take my cat off and put a test pipe. After a while I put the cat back on because I was seeing a lot of gray and black smoke. Even with the car being warm it stills smokes. I have replaced the head gasket and still had the same issue. I did a compression test and everything came out good with good compression. I also did a leak down test and everything came out good as well. We went and took the motor apart saw that one of the rings looked a little damaged so we honed the cylinder wall and put a new ring on. I changed the head gasket one more time, and even checked the turbo to see if it’s the problem. I have ran out of ideas on what it can be. Now it’s more like a gray color smoke and it kind of smells like corn in a way. I also put new stem seals. Can it be something with the tune, or maybe the fact that I went from a cat to a test pipe?? Any ideas??

 

PVC?

 

Remove the hose going from pvc to plenum and see if there's oil up in there

 

New pvc valve, but I’ll double check to see if there’s not oil build up

 

My y8/b7 sucks oil through into mani on startup despite pvc and hose replacement. Even cleaned breather box on back of block out. I finally just capped it all off because who cares, D. Still a perplexing problem

 

Welcome to the forum.

 

Found my issue it was the head. I am pissing oil from the head going into the headers.