Any vacuum lines that CAN'T see boost

[toki]

Is there anything like a fuel tank return line or something similar on the intake manifold or throttle body that wouldn't appreciate seeing positive pressure?

[Structure240sx]

everything is ok how it is. jsut dont use the hardlines under the throttle body for wastegate, bov, etc. they do not see positive pressure, so maybe there is a check valve in there or soemthing. i was using those from my bov and btm and they never worked until i moved the sources to the FPR line

[huguetpj]

everything is ok how it is. jsut dont use the hardlines under the throttle body for wastegate, bov, etc. they do not see positive pressure, so maybe there is a check valve in there or soemthing. i was using those from my bov and btm and they never worked until i moved the sources to the FPR line

Weird. I'm using my BOV signal from one of the hardlines and it works ok. Not all 4 see vacuum/boost but I'm sure one does and I think there is one more.