Rough idle with forced induction

Originally Posted by Mitco39

Just looking at the service manual now... It has 2 crankcase ventilation systems working together. Im not sure if my idea of putting it into the intake would be sufficient. Right now I bet the car is drawing unmetered air in through the lets call it primary ventilation circuit through the intake manifold. Now with the secondary ventilation circuit to atmosphere one could assume that its sucking air in through this secondary vent circuit into the crankcase then out through the PCV valve and into the intake manifold. Ill find a picture and post it up explaining that.

This would allow unmetered air to make its way into the engine, although when a engine idling it is supposed to be in closed loop which shouldn't affect its operation to much, however if the vacuum pressure in the manifold is changing slightly it would change the combustion process enough that could cause the hunt as it continually tries to stabilize itself.

I like thinking problems, lol.