PCV from passenger valve cover to plenum sucking tons of air all of a suddon

[Night Shifter]

A while back i had been chasing and idle issue which tuned out to me having to pull the pcv tube from the cold air intake to drivers side valve cover and vent it to release the crankcase pressure for my car to idle. im not sure what was causing excessive crankacse pressure since im only have cams and not sc'd but it did the trick...once vented i had no idling issues...i even pulled the pcv tube that runs from the passenger side valve cover to the intake plenum but put it back since i didnt have a breather for that valve cover or a cap for the plenum...

on sunday my car randomly developed an idle issue...well it wouldnt idle at all.. i decided i should pull the remaining pcv pipe since that helped last time...however when i pulled it, it was sucking in a tremendous amount of air...its a very loud wooshing sound...i know it's never done that before so it stumped me..

i went out and bought a new iac thinking maybe it just randomly broke and was forcing the pcv system to suck air...replaced the iac and the problem still exists... so now i am stumped...

what could be causing this? the block is an aluminator pre built from ford racing and the heads (minus cams) were prebuilt by MPH when they were around...could something be too tight in the drivetrain causing excessive crankcase pressure or maybe a piston not being sealed correctly? i checked all vaccuum lines, hoses and connections an all are good...even if i leave the pcv plugged up and pull the red vaccum lines that go to the egr is starts pulling air through that port...

im lost and need more suggesitons..

heres a quick vid:

2011-11-29_18-42-31_226.mp4 video by NightShifter6 - Photobucket

as of right now, i reset the tune and its running fine but usually it does until a couple days after the tune is in and the computer adapts to it...so right now i dont know if its the tune making it idle or if me resetting it fixed the idle issue...its still pulling air like a mofo though

 

[trinity_gt]

The PCV system pulls filtered and metered air from the intake duct, through the cross-engine tube to the driver's side valve cover. The air passes through the crankcase, picking up blow-by fumes and vapors and up into the passenger side valve cover. It passes through the PCV valve and is pulled into the plenum via engine vacuum.

The key part in all of this is the PCV valve. It should be very close to closed at idle. If you heard a great rush of air being pulled into the PCV valve at idle it's possible the PCV is bad or stuck.

The other thing is that if you've pulled part of the tubing out of this "closed' system ("...pull the pcv tube from the cold air intake to drivers side valve cover and vent it...") you've created a large vacuum leak unless you block off the plenum vacuum source.

Restore the system to its original configuration and consider replacing the PCV valve.

You should also check the intake ducting between the MAF and the throttle body for cracks or breaks.

 

[Night Shifter]

Sounds dumb but is the pcc valve the plastic price that pushes into the passenger valve cover? If so then I will go grab a new one...I can buy one at a standard parts store right?

The only time I hear a great rush of air is if I pull the pcc hose off the plenum. It never used to pull a great deal of air if the tube was off but now all of a sudden it does....this is why im really confused

 

[trinity_gt]

The SOHC engine came with a variety of different PCV valves so make sure you get the right one.

If you pull the line off the plenum where do you hear the "rushing"? The plenum port is a vacuum source and will suck a great deal of air (forming a huge vacuum leak at the same time...) if the line is pulled off. This is normal.

With the line pulled off the plenum port you shouldn't really observe much of a rush from the line itself since the other end is ultimately connected to the intake duct upstream of the throttle body and thus not really exposed to great pressure or vacuum.

 

[Night Shifter]

The rushing air is coming from the plenum port istelf. there is no type of vacuum from the line itself. not sure if you saw the video i posted but it shows how loud the air coming through the port is..

the thing is, i know there should be vacuum there but it just seems like it's an increases amount. i never heard the loud rushing air noise before but now the port has oil all over it and i can see puff's of white smoke at idle so its pulling oil through the plenum at in increased rate. Thats the only thing worrying me about the whole deal

thank you for the help so far btw

 

[trinity_gt]

The vacuum leak in the vid sounded perfectly normal to me.

 

[Night Shifter]

Ok cool... I wonder why the used to be no vacuum pressure before....maybe it just adjusted out of the blue and that's why it died?

If its being normal then ill just leave it alone...thanks for the help!

 

[mustangjoe02]

im not sure but on my 2002 gt, ive pulled that vacuum line off the front of my plenum before and my car stalled out. does this sound right?? cuz when you pulled it off in the video, it didnt die out. did your cars idle become eratic when you did that?

 

[Night Shifter]

it cam very close to dieing... the idle would drop really low when i pulled it but it would stay on and idle really crappy

 

[nyuk98gt]

If you disconnect the PCV tube so that it is open to the atmosphere then it will suck in unmetered air and the engine will run lean. Not surprising that the idle quality suffered.

Go get a new PCV valve at the Ford parts counter. Inspect the tubing for cracks and squeeze it (but don't break it) to confirm it is in good condition. If the tube is cracked then replace it. You can wrap it with electrical tape as a temporary solution.

Are you certain that the IAC valve is clean and in good condition? Often, a failing IAC valve will cause poor idle quality.

What about a vacuum leak? How are the vacuum lines? Are they pliable and in good shape or dry and cracked? A vac leak will foul up idle quality, too.

HTH,

Chris

 

[Night Shifter]

So far it seems the problem has went away....I reset my tune and ran the car a couple of days and it stopped its idling problem....it still stalls here and there if I take it out but that's expected with cams...plus I am in need of an updated tune... maybe the gas just went bad from where it sat for a few months