my perfectly rattling brand new pcv valve appears to be staying open at idle

car is a 305 tpi v8

what would cause a vacuum to be so great that it sucks up the valve to keep it open causing a rough/higher than normal idle with the car in park?

the spring inside too weak to close the valve?

please help the pcv is brand new and rattles but seems to be open all the time instead of being in different opening and closing modes for correct engine operation

 

The spring in the PCV valve opens it and the vacuum closes it. If the engine idles better with it plugged off then you probably have a vacuum leak.

 

anyone else want to agree or disagree or put in their 2cents?

most of my hoses are brand new and replaced my gaskets on the air intake setup

i guess i gota go over it but please keep sending your inputs

 

so if i have a vacuum leak it can keep my pcv valve open?

 

Not necessarily keep it open, it will act like it has 2 PCV valves, which is too much air at idle.

 

You should have enough vacuum at the valve to suck the little piston inside up against it's seat against spring tension. In that position it acts like a very small, calibrated vacuum leak, which is what it's supposed to do.

You can take it off and push the piston all the way down and try to blow through it- you'll notice it's a significant restriction. Let it off it's seat and you can blow through it with almost no restriction.

If it's not fully seated at idle (pull it out of the valve cover with the engine idling and check- make sure it's not down or vibrating near closing) you may have a vacuum leak prior to the PCV valve somewhere, a defective PCV or simply the wrong one for the application.