I was Wrong - PCV and Fresh Air

[j91z28d1]

there's many different throttle body's these days.. the old ls1 I remember was like that. but everything I've seen with a electric throttle has the intake hose got into the rubber or plastic air duct.

 

[ExEl03X4]

If it is behind the blade on the throttle body, there will be vacuum on it when the blade is closed. As you open the throttle blade the vacuum will decrease and then increase as the throttle body closes. It's very easy to test by temporarily adapting a vacuum gauge in the vacuum hose an observe how it behaves. Bottom line here is, anything on the intake manifold side of the throttle blade will see vacuum. Any air in the intake will be "fresh" until fuel is introduced at the sight of the injector. Vacuum gauges are an essential diagnostic tool. Even on today's modern cars and they are not expensive.

 

[Just Fishing]

On my C4 vette, I played with the idea of just dumping the PCV system and tried to do an open "filter" vent instead.
What I got was a test of every seal in the engine, a mess, and the nasty smell of hot oil on hot summer days.

I very quickly went back to the PCV but added a catch can to prevent the snail trail of oil going into the #2 cylinder that I saw originally.