Alright so I finally got my 2009 cobalt ss with 6758 and full bolt ons tuned by zzp LNF PCM and let me say it runs amazing now. I also purchased GMS1 sensors which fixed my sensor check engine light. Now the car runs great and pulls very hard but like before I am still only pushing 10lbs of boost. I thought because the bad sensor or tune was why it was only making 10psi but the new PCM i got says its tuned for 22psi. I emailed them about the problem thinking it might be the wastegate but they told me the wastegate already comes pre-loaded. So if its not the wastegate what else could it be?

 

Check the pre-load, and check for boost leaks

 

Have you checked for boost leaks?

 

No I haven't. I'd figured if i had a boost leak I would get a code. As for pre-load how do i check that on the efr 6758. I was told it has an interal wastegate so is this still possible? also where should i look for boost leaks?

 

Did you get it tuned after you changed the sensors? You must change the calibration for those sensors once you change them to the 3 bar map sensors.

 

Yes i ordered the tune with it being tuned for those sensors

 

Okay i am pretty sure i found the boost leak. There is no vacuum line going to the by pass valve on the turbo. The only problem is i cannot find a vacuum line that isn't connected to anything. Am i suppose to tap into another line in order to run it to my bpv? Here are some pictures and it would be nice if someone could tell me which vacuum line is suppose to go to the bpv. thank you.