Hey guys I have seen a few threads on blocking off the pcv valve. I have heard that just blocking off the pcv valve and then the vacuum hose is bad but y ? When I purchased the car the pcv valve was already blocked off. It has a bolt to seal it off on the hose and then another bolt on the vacuum hose and then a breather filter on the oil cap. What do you guys think about this setup? I might consider hookin it back up but I would need a picture of the engine bay to see how to hook it back up . I have searched for some but found none lol. I have seen the oil separator kits but I don't have the cash to spring up for one of those . Any ideas or suggestions would be very helpful thx.

 

Totally blocking off the PCV is very bad. However having it vented like you have is ok. I would rather have the PCV hooked up as it makes vacuum in the crank case and helps to make the rings seal better etc... It can also mess with your air/fuel ratio as that is unmetered air that is no longer going into the motor. I had constant a/f ratio problems on my f150 when I vented mine (I did not know better when I was 18).

 

That part about the fuel ratio i do not understand because both hoses that are coming from the intake lead somewhere one is to the IAC the other one lead to the driver side valve cover so what does this mean?

 

Like I said if you plugged all the PCV hoses going to the intake and plenum then you will make the a/f ratio change because it no longer would be sucking in that extra air that it would of before hand taken in.

 

do you think you could maybe post up a pic of how the stock pcv valve setup is that way I can get a better understanding lol...

 

It's a circle. You have vacuum on the PCV side coming from the intake manifold which draws air out of the valve cover. This creates negative pressure in the crank case which is GOOD for a lot of reasons. The breather tube is plumbed into the intake snorkel after the MAF so that the MAF meters the air that the breather side uses to replace the air ingested by the intake manifold through the pcv from the crank case.

It's all a balanced system. If you block it off completely or replace it with breather filters you lose the vacuum pump effect and crankcase venting then relies on convection which don't work so well through small tubes. If you put a breather filter in one side and allow the PCV valve to stay connected to the intake then you've just caused a lean condition every time you go to WOT. That will eventually cause a problem. Disconnecting one side blinds the ECU to the amount of air being ingested through the vacuum ports on the intake and is bad.

Just put it back how it goes or buy one of my OAS kits.

 

I would also recommend keeping the PCV system hooked up like my man Red said.

 

What about the oil in the intake is there another way to fix that other than the OAS kits? An image of how this goes would be really helpful.

 

not really. There are images on my site... were those unhelpful?

 

Ok hadn't seen those saw them now so pretty much the pcv valve hooks up into a hose that goes into the plenum like right next to the IAC correct?

 

yep. The breather air exits the intake tube and goes into the other valve cover.

 

Cool man I understand it much better now so the method I am using now should be ok right? I just bought a diablosport predator tuner is there anyway I can adjust something with it so I am not lean at WOT?

 

Without having a wideband on the car to know the a/f ratio its a crap shoot.

 

I would bet that you have a half a PCV system. Without seeing it up close I can't be sure but I'm willing to bet that it's not performing how it was designed to. You need to put it back to the way it should be. If you require assistance I'm sure we can help a little.

You can not know the air fuel ratio without a wideband. I would go to a dyno and do a quick run. See if it's excessively rich or lean and take corrective measures as necessary.

 

definitely need assistance if you could guys give it 2 me it'd b great

 

What did you need assistance on? Maybe I missed something here.

 

please post detailed pics of the routing of your PCV and breather lines. Include close up shots showing where the lines all go. Label them if necessary. I'll see what's wrong with it and tell you how to fix.

 

Great R3d!! Ill get them up as soon as i can.

 

Ok I got best pics I could with phones camera (pretty decent for a phone camera) lol. Let me know what you guys think of this setup . I forgot to take one of the pcv valve itself but its just in the valve cover with a hose on the pcv and a bolt in the hose to seal it off.

 

I do not know why someone set it up like that but its wrong the way it is. The way it is now is that it has capped off the passenger side tube that runs from the plenum (thing with the horse on it) to the passenger side PCV on the valve cover. Then the driverside PCV valve is still connected to the intake like it should be. They way it is now it is sucking in air from the breather on the valve cover (assuming one is there I cant see in the pics) and from the breather where the oil fill cap should be (one with the ford motorsports logo on it). This is the unmetered air I was talking about. Because its sucking in air from those two points threw the driverside PCV as its still hooked up.

I would **** can the breather on the oil fill tube, and on the valve cover. If you look on your plenum (thing with the mustang on it) there is one tube on the front all the way on the driverside with a plug in it. That is supposed to be connected to a plastic tube the runs over to the passengerside PCV and connects there.

So basicly someone half assed it thinking they were doing a performance mod I would guess. I would hook the PCV back up and enjoy better ring sealing and less exhaust and engine fumes.

 

OMFG.... seriously spike's nailed it. You've got the BIGGEST vacuum leak I've ever seen. You may as well not have a bloody engine computer cuz' it's sure not getting all the data.

You gotta get a proper oil cap. That'll stop the vacuum leak. That is a MINIMUM and still leaves you without crankcase ventilation in any real way.

To fix the rest of the problem, just like spke says:
Connect from the front driver side corner of the upper plenum to the PCV valve on passenger side valve cover under the intake tube. If you need the plastic tube that goes there, go to ford. DO NOT USE RUBBER HOSE IT WILL ROT AND COLLAPSE. Small rubber couplers are fine. No big runs.

From the intake tube to the driver side valve cover, is a long 5/8" ID plastic tube. Make sure it's unobstructed.

If you want one of my kits, LMK. Should run about 150 bucks.

Breather filter thingy... **** can it.


EDIT: Them's good Caster Camber plates you got there.

 

Well I only have one breather its installed on the oil cap. On the passenger side the pcv valve is still there but blocked off. Does this make a difference because spike stated I had 2 breathers but I only have one. I understand now how to re hook the pcv valve back up but then I will have the problem of oil going into the intake how could I fix that other than the kit bcuz I just don't have the cash to spend on it right now with all the x mas shopping and a new college semester comin up. Is there a way I could block it off somehow and not create major harm 2 the engine. Thanks

 

Well if your still concerned about the oil and can't get the OAS kit right now, then the only thing you can do to make it "right" is to get rid of the line running from the driver side valve cover to the intake tube and put a breather over there.

 

I guess you could also do like r3d said and get a regular oil cap just to eliminate the vacuum leak, but if you are trying to eliminate the PCV system anyway, why not go all the way?

 

I will get the oil cap immediately but how else can I eliminate the PCV? Wouldn't putting a breather on the other valve cover cause a vacuum leak just like the breather on the oil filler cap is causing a vacuum leak? Also if i block off the hose from the intake wouldn't I be causing a major lean conditon? That's what I've heard from many people.

 

The oil going into the intake really is not that big of a problem. I don't have much oil residue in my intake when I clean it so I would not worry about that its not going to harm the motor. Later on you can buy an oil separator or make your own if you wish. For now hook it back up like it should be and move on.

Also the fact that you have one breather does not change the fact that its sucking air in from the oil breather into the motor. I'm surprised your car does not run like **** setup like that. Or maybe it does I don't know over the internet.

 

You've got a vacuum leak now because the system is vented to the atmosphere via the breather on the oil cap, i.e. open-ended. If you block off the the other line, then you have closed the system back up in regards to the intake system. Of course the crankcase would be open seeing as it is vented on both sides now, but it would now be totally separate from the intake system.

True, blocking off the hose might mess with the A/F a bit, but nothing a tune can't fix. The air that was once being used by the PCV system would then be used purely by the intake system. For normal driving, the computer would make the appropriate correction for this without a tune, but WOT could be affected.

Is there a reason why you are so worried about the oil in the intake? On a basically stock car, I don't see why it matters all that much. Yes, I know what the "problem" is, but in your case, you are stuck in the middle. You need to choose one side or the other: either put it back to stock and deal with the oil until you get the OAS kit or completely delete the system. As r3d said, just doing the oil cap won't eliminate the crankcase ventilation problem.

 

You know I knew something was wrong because when I put the regular oil cap on it felt like it ran better not crazy stuff but yes little better. I guess I will return the setup to the original way and I'll clean the oil off the intake every oil change or so. I'll check out how much oil gets in there. Anywho if theres an ok way to go around the pcv system without having to buy the kit I'd like to know. Thanks for all the help guys especially spike.

 

to make the system work right just put the oil cap back on and reconnect the PCV valve. The rest is fine from what I can see in the pics. Should be nearly free to do that.

Do the kit when can and if you want. It's not totally necessary but it's a nice setup.

 

Well I have heard oil in the intake messes with the octane level of the fuel that is being put into the mixture with air in the motor is this true? I use it as DD quite a bit but I also like to race it and take it to the track. I just want to get some good performance out of it without loosing the ability to use it as a DD. Can anyone explain what the oil in the intake actually does?