There is a little check valve on the vacuum system. It connects just below where the factory air bypass valve vents back into the intake.

Which direction should it pass air? Towards the air intake or away from it?

Page 5 on the S4 FSM section 4B

Thanks

Jack

 

on the next page:

"Supplies the blowby gas and evaporative emission gas into the turbocharger when the intake manifold vacuum becomes positive pressure"

so it should allow air to flow into the intake.

There is also a small arrow in the diagram, but it's hard to make out.

 

Damn, beat me to it.

 

thanks! there is a little arrow on the check valve, too.

preciate the help.