Vacuum on PCV and other valve cover hose? Engine running fine with these off! (1 Viewer)

[e9999]

was playing with the PCV and the other valve cover hose yesterday.

when disconnecting the PCV (it's almost new) I could indeed feel a strong vacuum in the PCV with engine idling. Interestingly, though, disconnecting it did not seem to affect the engine idle much at all. Based on discussions here I was expecting that the engine would struggle. Didn't do that at all...

OTOH, I did not feel any suction at all with the other hose. Is this normal? Is it plugged maybe? I was expecting some vac. IIRC that one is before the butterfly so probably not much vacuum there, but I thought there would be some. And what is this hose for anyway that the PCV doesn't do already?

 

[Tools R Us]

The "other hose" is a breather, allows clean into the engine.

 

[e9999]

The "other hose" is a breather, allows clean into the engine.

clean air you mean?
it's connected to the throttle body from what I saw so for sure under vacuum in a normally aspirated engine, though. Unless the space under the valve cover is under even greater vacuum, that hose would not introduce air into the valve area, I would think.