Smoke tests - Pre Turbo Exhaust leak questions

[hyjnx]

I have a 2005 LGT 5eat.

 

Since I upgraded my uppipe I have been having issues with my idle. Whenever I come to a stop the car wants to stall out. Here is a list of what all I have done:

 

Replaced OEM uppipe with old catless flexpipe uppipe.

smelled exhaust whenever I got into boost with the windows down. even on the highway I would smell it.

took it all apart noticed small carbon build up at uppipe > turbo

replaced flex pipe uppipe with jdm OEM subaru catless uppipe.

replaced all exhaust gaskets with brand new OEM subaru 3layer gaskets.

got car tuned for new uppipe.

car still tries to stall out.

took logs for tuner. he is stating it looks like a pre turbo exhaust leak.

took everything apart again. didnt see anything. rechecked all tightnesses.

 

Since I have gotten a boost leak check (Passed beautifully) got a compression test, passed that as well.

 

I can still smell exhaust fumes when the boosting and the windows down.

Im looking to preform a smoke test on the exhaust to find out where my leak may be coming from. I was wondering if i put the smoke through the muffler, will it pass through the turbo and enter into the header? Or do i have to insert the smoke through another area to get it through the turbo.

 

 

Any help is appreciated, im getting sick of the car wanting to die whenever i come to a stop.

[BarManBean]

In theory, going through the exhaust might work, but you are much better to pull the small hose from the BPV and add smoke there. Or you can undo the intake hose and add smoke to the after-MAF hose (pre-inlet) if you have the right adapter.

 

I have a smoke tester if you want to come down to Springfield, VA. When I smoke test cars, I add smoke with 1 psi to check for vacuum leaks and then I pressurize the system with the smoke added to check for boost leaks. I'm likely cheaper than shops and can do it afterhours with you if you'd like.

[willg]

Another good way to check for exhaust leaks is to use a feather or small piece of thin paper and hold it next to exhaust joints. You can see the paper flutter. In your case, it might be worth checking the secondary air injection valves, or whatever subaru calls them. If one of those is stuck or leaking it could allow exhaust fumes to come back up the air injection pump.

[Minty762]

You probably already checked it, but I had a hanger break off the downpipe between the front and rear sensor. That caused the exact same problem you describe.