Post by
Chris859 »
https://forums.nicoclub.com/chris859-u44940.html
Sun Mar 11, 2007 12:44 pm
That is the air inlet that works with the pcv system, it needs to have filtered air. If you just leave it open you are just sucking dirty air, and contaminating your crankcase. Not to mention, it will also be an un-metered air leak if left open(bypassing the maf, causing a lean condition, possibly stumbling, poor idle, etc). To put it simply - if you don't know how the pcv(positive crankcase ventilation) system works, here it is. the Pcv valve uses vacuum from the intake, to put a vacuum on the crankcase, which pulls in filtered air through that breather tube... The basic principal is to circulate fresh air through the crankcase, while burning the vapors being drawn in through the pcv valve rather than venting them.