TT2005CREW

Truck is a 2005 5.3 with Z06 cam and springs. Twin front mount turbos with drains going into the front of the pan under the crank. Its been dyno tuned speed density with the pcv as follows: Driver side--valve cover vented down to ground and the vacuum port on top of the intake capped off. Passenger side--valve cover vented to ground and oil fill cap stock. Back of throttle body is connected to port on BOV. If I start the truck up cold, within 2 minutes it is belching smoke out the driver side exhaust and smoke is coming out around downpipe flange on driver side turbo in engine compartment. But only at idle. If I drive from a stop it clears up, but starts the next time I come to a stop. Driving down the highway, I have not had any problem. So I took the driver side valve cover vent and reconnected it to the vacuum port on top of the intake. Started it up cold and let it run for 20 minutes and only get light wisps out of tailpipe. I then unhooked the line from the top of the intake and within 15 seconds it was pouring out the tailpipe and smoking around the downpipe flange. Is my crankcase pressurizing and not letting the driver side turbo drain? If so what should my proper pcv setup be? I know I will have to have it retuned if I change anything but at this point I don't care. Can I run a catch can and one way check valve to the intake on the driver side like stock and the cap off the passenger valve cover and run an oil fill cap breather? Any help is dearly appreciated!!

02'Z71ONDUBZ'

iTrader: (8)

Have you done a compression or leak down test on the driver side of the engine where your having the problem at? Your PCV setup needs something done with it regardless. At the least, connect both the hoses to a catch can with a breather on top. Personally, I would run a PCV with a check valve in it to a sealed catch can, and then from the catch can back to the intake. Cap off the passenger side valve cover and install a breather for your oil fill cap. This will allow your PCV system to work like normal when your not in the boost; when you hit boost, the check valve inside the PCV will engage, preventing you from boosting your crankcase. The breather will allow your engine to pull fresh air as needed under vacuum, and vent crankcase blow-by when under boost. Everything is sealed up so no oil residue like your probably getting with your drains, also no fumes to deal with.

I don't see any way your crankcase could be pressurizing with your setup now. Your drains should be venting any pressure that could build up, and your not boosting at idle anyway. How exactly can you tell that your not still having the problem while driving and it's just not as noticeable? I would test bank 1 asap and try to rule that out as the problem, but from what your saying it sounds like it could be hurt. Also, it could be a turbo oiling issue, but it should get worse when your driving at a higher oil psi unless you have some sort of restriction in your drain line. How high up are your drains on the oil pan? Are they right next to each other? You could check your tubing below the turbo for oil residue.

Gadgetized

iTrader: (9)

Did you run restrictors in the oil feed lines to the turbo?

TT2005CREW

No I haven't run restrictors, I figured that they would both smoke if I needed them. I have -4an teed off of the feed port, -10an drains and oil pressure is 40psi to each turbo.

TT2005CREW

Ok I just did a quick compression test. Motor was not warmed up so all results are with cold engine.
#1-150psi
#3-155psi
#5-150psi
#7-130psi

02'Z71ONDUBZ'

iTrader: (8)

Looks like #7 might have something going on, that seems a little low. Not positive on these motors but you don't really want more than a 7psi difference on all cylinders on outboards. #7 is notorious for being the cylinder that goes down too.

Gadgetized

iTrader: (9)

Run a restrictor in each turbo. You should always run them, the turbos can't handle all that oil.

TT2005CREW

As to restrictors, they are just journal bearing turbos and I thought that only ball bearing turbos needed them for sure. I'm also confused why the oil starts and stops when I hook up the vacuum or disconnect it and let the driver side vent. Within 15 seconds of disconnecting the vacuum it is smoking around the downpipe flange and if I immediately hook it back up then within 30-60 seconds it is not smoking from the flange anymore.

TT2005CREW

Ok guys just wanted to let you know what fixed the smoking. I put a one way check valve and catch can on the driver side between the pcv and intake manifold and opened the passenger side to atmosphere and no smoking since. No matter how long I let it idle. Thanks for the help!

02'Z71ONDUBZ'

iTrader: (8)

Glad to hear you got it fixed. Did you have the driver's side valve cover running to the intake when it was smoking? I thought you had it vented with the intake capped off, and can't understand how plumbing the pcv through a catch can back to the intake would cause it to stop the smoking. Were you having alot of blow by coming out when you had it vented to the ground? We should meet up sometime I would like to check your truck out