I recently replaced my pcv (about a month ago), It didnt really need to be done since after shaking it I could hear the valve giggle so it wasnt stuck or anything (it was about a year old so it was really due to be replaced anyway).

Well what I wanted to get at was the design of the PCV, or more on how the rubber hose leaves the pcv. I noticed that it makes an immediate right turn, so after installing the pcv and you were to fully push the rubber hose onto the pcv (like most of us would) there is a good chance it will restrict the engines ability to pull air through it. When noticing this I decided to pull the rubber hose back a good amount, but so that the clamp still worked well and held the hose properly. So whats the result? Well the idle is at least 100rpm higher! Its so much higher that I might reset my ecu soon.

Since many of us have had a poor idle at one time or another I thought I might shed some light on the subject a bit. When at an idle the throttle plate is closed, So where does the engine get its air from? The first place is through the IACV, which is limited due to its construction and the electronics controlling it, meaning the pulse width that the ECU sends the IACV can only be so great and on its own may not be enough air for the idle to idle smoothly. The second place is the PCV, and if its restriced by the hose that is attached to it, it will limit the amount of air taken in during idle. Air being su-cked in by both the PCV and the IACV is registered by the MAFS and contribute to the overall air consumption for a good idle.

I dont know the layout of the PCV for the vg, but maybe someone can check it out and post their observations.

 

hmm...thats an interesting thought....I'll have to check that out on my vg.

 

i replaced my PCV and noticed no difference what-so-ever. i'm thinking about taking the fuel rail lookin' thing off and putting two small filters on each of the hoses that lead to the valve covers. any idea?

 

yea my idle is somewhat rough, maybe doesnt feel as much b/c im used to it

 

Very interesting.....

 

definately will replace that junk...i finally got my iacv spring (off an old 300z lol) and my car idles halfway normal again...now i just gotta get the idle, tps, timing, and now pcv workin right cause my idle is 2 low now in drive (round 500 hehe)