Yes I did a search.

I still fail to see how removing the PCV hose from the valve cover and installing a breather can create a vacuum leak if you plug the port on the TB.

If that port is closed then no air enters the intake (from the crankcase) and makes its way into the combustion chamber and so there is no lean condition to be corrected by the o2's.

The reason I ask is, my pcv hose now has a huge tear in it and I don't feel like replacing it.. pluse the valve cover end fits very very loosely into the valve cover so I figue it probably leaks. Right now I have the port plugged and a sock over the PCV hose (a make shift filter.. yes.. sad I know). If I definately need to replace the system how much is it gonna cost? Anyone have a part number?

 

everything you need to know is explained in this thread

http://web.camaross.com/forums/showt...&highlight=pcv

 

The PCV valve on the driver's side of the engine pulls air through the crankcase. That air comes from in front of the TB blades, through the hose to the passenger side valve cover. Since that air is coming from in front of the TB blades, it has been measured by the MAF sensor, and is included in the A/F calculations.

If you "open" the system by removing the line from the TB to the valve cover, you will be pulling air into the combustion process that has not been measured by the MAF. The PCM will have to alter the long term fuel corrections to make up for this unmeasured air. No big deal, and nothing that the long term corrections can't handle.

Appears you are under the impression that the hose on the valve cover allows vacuum in the TB to pull air out of the crankcase, and that is incorrect. Vapor will only flow in that direction to relieve pressure buildup in the crankcase, caused by a faulty PCV valve or excessive piston ring blowby.

 

I've already read that thread.. TWICE.. thanks though



Fred, I know you feel like you're beating a dead horse.. but..

I understand that all the air inside the engine has been metered by the MAF.. the only way air can get into the crankcase is through blow by and through the PCV system both of which pull air from the intake that has been metered by the MAF... I understand this part.

What I don't understand is, if I plug the port on the TB then how can any metered air escape except through the combustion process? And, the million dollar question, how can air enter the combustion chamber but through the MAF (remember the port on the TB is plugged)? The way I see it outside air will enter and leave the crankcase at will with a breather but I fail to see how any of that air can get into the combustion chamber.. The only way air is gonna get into the combustion chamber is through the TB and all that air is metered by the MAF. I fail to see how the PCV port allows any air into the combustion chamber.. it only vents air from the crankcase (air behind the piston rings) and I don't see how any of that air matters since it isn't being burned during combustion (has no effect on richness or leaness). I know, if I'm arguing with you Fred I've gotta be wrong but I just don't see how

Regardless, is there a cheap way to replace this valve? Do all of the filter type things (theres a fram, deustch sp?, and a couple others) could I just drop one of those in and then route the little nipple/vent thingy back to the TB with some vacuum line? I just want to fix this thing right on the cheap.. if the PCV system is like 10 bucks then I'll buy a new one but I have a feeling it's not. I'll go check gm parts direct I guess.

 

unmetered air can be sucked into the motor like this

breather filter on valve cover > pcv valve > into the intake via vaccum port

thus creating a small controlled vacuum leak.

this is the way i run my lt1.

 

It's apparent from your comments that you simply don't understand how the system works in the first place. There is air in the crankcase. It is put there by the vent line from the throttle body (the crankcase is under a slight vacuum because of the PCV valve being connected to a vacuum source), to sweep the combustion products (including water vapor) and oil and fuel vapors out of the crankcase, so they don't condense and turn your engine oil into a bath of acidic slop.

The air in the crankcase gets pulled up through the lifter valley, goes through the holes in the metal pan that covers the bottom of the intake manifold, and through a thin slot in the bottom of the intake manifold, to the PCV valve. The other end of the PCV valve is connected to a vacuum source.... the plenum of the intake manifold. (On the early models, its a connection on the drivers side of the engine, on the later models and some early emissions variants, its a small connection of the front of the intake manifold, under the throttle body.).

Hence, the air that is in the crankcase gets pulled out of the crankcase by engine vacuum - through the PCV valve - and into the intake manifold where is joins the air entering from the throttle body, and gets pulled into the cylinders to get burned in the combustion process.

What part of this do you not understand???????

 

I was unaware that the crankcase was under vacuum. In fact I was wondering what that hose under the TB was for.

I understand completely.. thank you. Again sorry to make you beat a dead horse. I thought the PCV system was merely a vent..

I'll have to see about getting a new hose/valve assembly for the passenger side valve cover.

Anyone have a part number? GM parts direct only gives me one hit - 25095452 and I don't think that's the part.