blacksheepZO6

This is my first post here, and it's kind of long winded, so I appologize in advance if this has already been covered somewhere, but here goes. I have an '03 ZO6, bone stock motor with an intercooled STS rear mount turbo kit running 6 PSI. Kit has been on the car since approx. 75K, it now has 103K on the odo.

It's been just fine until recently when it started smoking out the exhaust pretty bad after going into boost. It seems to run as normal under all other conditions except for boost. After a short burst it wouldn't smoke much if any, but immediatley on lifting off after a long (2nd to top of 4th) pull on the highway she'll puke oil smoke like crazy.

I've done some digging and discovered large quantities of oil in the intake and in the intercooler. Checked the turbos and they appear to be fine, plumbing appears to be dry at the back of the car on the compressor side, so I assume the oil in the intercooler is coming back from the intake when the BOV pops open. I noticed that the crankcase was becoming pressurized under boost, so I replaced the check valves that seal the crankcase PCV system from boost pressure and still had the same issue. I've also tried eliminating the PCV altogether and just venting the crankcase to the atmosphere, and I'm getting a good amount of oil vapor/smoke out of the plumbing, and still the same issue with oil in the intake/IC. Where's it coming from?

Does anyone have any expereince with anything like this? My sinking suspicion is fried piston rings/lands, or hopefully valve guides/seals but before I go tearing the engine to pieces I thought I should ask if anyone else has had this issue.....I'm flat out of ideas short of tearing the block apart, so any input whatsoever would be very much appreciated, thanks!

mike13

iTrader: (27)

Do a STS search there are many threads on these types of problems. Not trying to be difficult just that there is so much info that just the search will keep you busy for a while.

sujomatt

iTrader: (7)

ull get vapors coming out of the vented system - expected... is the intake piping coated with oil? exhaust piping? thats a lot of miles

knappbunch

could be oil pressure getting past the turbo need a restrictor in the oil feed line to the turbo (common problem) or one of the seals on a turbo is going bad and letting oil by under load. call chris at STS he is very good guy and will answer your questions. call back and keep calling till you get him though he is a little hard to get ahold of sometimes.

Camaro01SS4life

iTrader: (4)

There could possibly be oil setteling in the turbo which is causing the smoking...Did you look over the oil pump setting(STS return pump), or make sure its working properly?More than likely this is the problem if its only smoking under boost conditions...

Kev

blacksheepZO6

thanks for the replies, however as I said in the original post the turbos themselves aren't the source of the issue. The piping on both the hot and cold sides is dry, no oil at all. the only place I have located any oil where it should not be is in the intake manifold. I thought the oil was coming through the PCV system and it appearantly is not. So the question is where else could it be coming from?

The Fugitive

iTrader: (6)

with oil coming in the intake would not cause the puff of smoke under boost if that was the case it would be more constant even out of boost. try doing some pulls at 0psi and see if there is any smoke but it may be that your STS pump isn't kicking into high. Did you get rid of the that pcv check valve and put in a catch can that would help keep the oil out of your intake along with a restictor before the turbo and the pump running on high all the time. Do the oil mod that Scantin did and see how it goes along with the catch can and report back to us.

venom ws7

iTrader: (13)

This is the same reply I got when I asked your same question

the oil scavange pump is not working.
or
oil seals in the turbo are bad

It turns out to be the 1st one I changed the small STS Oil pump to Mocal pump
or you can use the new STS Oil system

shawn_c992001

You have a PCV problem. Do you have the PCV switch hooked up still? I see you are in CA so you can't readily delete it and get away with it. My switch came loose one time and was doing the same thing, filling the intake with oil. When I got on it it would smoke like hell. I bolted the switch down tight and problem was solved. The PCV switch is grounded when the body is bolted down (Normally open)and then a 12v signal is applied when 1psi of boost is applied (switch closes) then it vents to the atmoshere through some small filter on top of the switch.

To check and see if the switch is closing, just apply 12v to the post on the PCV switch and listed for a click. If the switch is working an audible "click" will be heard, and you can move on to other options. I'm betting 99% that, the switch is your problem. Usually the simplest things are the hardest to troubleshoot, and usually the most often over looked.

Basically, what you are doing right now is filling your crank case with boost.

blacksheepZO6

Thank you all again for the replies, however I may not be explaining the issue properly. The crankcase is deffinitley becoming pressurized somehow, though I have confirmed it's not through the PCV system. I have double checked the PCV system check valve and solenoid and all is working properly. The oil scavenger pump is running on high all the time and scavenging properly. The turbo oil seals have been checked once and deemed fine, to be safe I'm having them looked at by another turbo shop just to be sure. Taking this into consideration, where else could the pressure be coming from?

blacksheepZO6

Oh also I wanted to mention that the only time the smoke appears is immediately AFTER lifting off the throttle. While in boost there's no smoke.

devilssled

Dont buy sts its junk sell the kit as fast as u can u will save u so much trouble in the future

blacksheepZO6

to devilssled, just my 2 cents but I love the STS kit, its been great with the exception of one failed oil pump and this little glitch, which I'm betting has alot more to do with the mileage on the engine than anything else, if it doesn't turn out to be some small issue. Also the fact that it's smog legal in CA is kind of an important feature for me. What experiences do you have that makes you say STS is junk?

The Fugitive

iTrader: (6)

hmmm are you running a oil catch can and a breather?

chase3

iTrader: (1)

you bash sts on all these threads..Why?? just because you live by them doesnt mean you have any experience..everyone else on here that has an sts kit loves it....

josepy121380

iTrader: (21)

I love morons like you. I know tons of people who have the sts kits and they work great if you install them properly.

blacksheepZO6

well it seems weve gotten off of topic here, whatever your preffered choice of power, does anybody have any other ideas on what's going on as per my original question?

RooRnZ28

iTrader: (14)

this is the twin system, correct? how is your pcv system routed?

did you say there was oil in the intercooler as well?

does oil pool under the car(under turbo, oil pump) when you let it sit for awhile?

could be a bad oil pump, or even a check valve....

shawn_c992001

Happens when you lift off the throttle after being in boost? That's strange.... I would have betted my left one it was the PCV system.

blacksheepZO6

RooRn, yes it is a twin system, PCV is set up as per STS instructions, check valve in the cam cover vent line and electronic solenoid in line to valve cover, and all of it is working properly. No oil under the car whatsoever, its not coming from the turbos themselves. There's oil in the intercooler but it would seem its coming down from the intake manifold when the BOV pops off.

Shawn, you and me both.....i thought it was either a failed solenoid or a turbo oil seal as well, been through all that and no dice.......so im kinda stumped on this one. so far nobody seems to have any ideas, so im guessing this isnt a common occurance whatsoever. im going to start tearing things down again this weekend and go through everything one mroe time and see if somehow ive overlooked something, however i don't hold much hope for that as ive already been through all the common stuff 4 times now.......