[trapahh]

My car can’t seem to hold boost when trying to achieve around 13psi or higher. Let me be more specific. Target and boost output seems to match around 10psi but when target wants to be 13, I see 11, target 15, actual boost 13, target 16 actual boost 14. You get the point. Whenever I WOT to try and achieve that high boost, I can hear a hissing sound on the driver side. I feel as if I have a boost leak because air is going somewhere but my mechanic said everything checked out and the smoke test passed. I feel as if the leak only comes when the system is pressurized. If anyone has had this problem can you guys please help. Thank you

[srey]

A smoke test won't help you find all boost leaks. You need to do a pressure test. I was chasing boost leaks all last spring, and finally found the issued in my lower charge pipe. The smoke test didn't get it, but the pressure test did. Make sure you disconnect and cap off the PCV breather hose in the rear inlet when you do it.

https://www.e90post.com/forums/showthread.php?t=193077

[Darek335i]

Can the problem be caused by "leaking" BOV? I also have the same issue and I can hear a quiet hissing close to them.
Thanks.

[Chris@VargasTurboTech]

Boost leak checks with target boost levels of pressure make a lot of mysterious boost leaks become evident.

Chris