[joyism5]

This is my first post, I just wanted to clarify the operation of the ccv valve
The amount of air is often dependent on intake manifold vacuum. The ccv on the other hand is designed to ONLY open when there is an ABSENCE of vacuum in the crankcase. The diaphram in the ccv will be fully open upon startup for a brief second until engine vacuum accumulates in the crankcase, at which point the valve will then close.

Nice post Corey. Not to disagree , I do have a question :

Are you trying to say that Is designed to be always open and close when the flow is big through it? If yes , sorry for question. If not, I'm all ears...
If you take the positive crankcase ventilation valve and suck air through the hole where the intake pipe is connecting you will see that you can always suck the air. But if you change the speed of the air absorbed the diaphragm will close . This makes me believe that air is going through the diaphragm at all the times and it is open but is closing when the pressure on it is greater. For instance is open when the engine is idling or the rpm increase until a certain point and under a sudden acceleration is closing. So with another words it does not allow more air than needed to be absorbed by the intake vacuum.

I might got this wrong , and if I did please make some light on it.

This is a Quote from alldata :
Purpose :
The Positive Crankcase Ventilation Valve (PCV) system directs crankcase "blowby" to the intake system in order to prevent vapors from escaping to the atmosphere.
How it runs:
The blow-by gasses which are produced during engine operation collect in the crankcase.

The crankcase is ventilated by a pressure controlled system. The oil vapors in the crankcase enter a cyclone-type liquid/vapor separator (OSV-behind the timing chain) which allows the liquid oil to return to the oil pan and the oil vapors to be drawn into the intake manifold via a pressure control valve.

The pressure control valve is centrally located in the rear end cover of the intake manifold and is connected directly to the cyclone-type separator via aluminum pipe. It varies the pressure in the crankcase continuously depending on engine load and speed conditions. This prevents blue exhaust smoke and excessive oil consumption on deceleration due to peaking manifold vacuum, and assures reliable crankcase venting during all other engine operating conditions.

So knowing this, is the PCV always open and close under big pressure conditions?

UPDATE: This is a must read for those looking for more information : http://www.bimmerfest.com/forums/showthread.php?t=534005

 

[joyism5]

Ok. This is exactly what I did before and I understand that the gases are sucked not pushed.

Are the blow-by gases produced continuously when the engine is warm and running?

Do they need to reach a certain pressure before they are let in the intake ?

If not, because the gases are produced continuously -> the pcv is slightly open continuously( if there is a perfect seal in the crankcase) so the gases can be let into the intake?

If there is a leaking gasket the pcv will close so it does not let the blow by gases to the intake? and this makes the rough idle?

The only way air can enter the crankcase is due to blowby or a leaking seal/gasket.

What about the air pump? From my understanding it does take filtered air and is pushing it, into the crankcase when the engine is cold. Is this I guess to back-up the lack of blow-by gases which are produced when engine warm only? Or I can't see well enough and the pipes are going in the cylinder head to push the air in the exhaust system to lower the emissions when engine is cold?

 

[joyism5]

Thanks for letting me understand better how this system actually works. I got it clear and light now. So gases are sucked in the intake and if there is a leak in the crankcase, it will make the lean mixture.
When I first start to fix this issue and read it I got it a little wrong :I thought that the the blow-by gases produce such a big amount of pressure that the pcv will be open all the time, when actually the blow-by are produce in such a small amount and the pcv is more closed than open . Because of the design I thought that the air pipe is going in the crankcase, not in the cylinder head/exhaust port. And again I couldn't find the right information for it.

Thanks again :thumbup::thumbup::thumbup:.

 

[joyism5]

Also, just to clarify, the metal pipe connecting to the ccv does go to the crankcase. If your engine uses an air pump, which the pre vanos m62 does not, then the air pump will be pulling fresh unmetered air and pushing it into the exhaust manifold, not the head. (the silver disk looking thing sticking up from the exhaust manifold, usually has a vaccum line attached to it)

Yeah that aluminum pipe does go in the OSV/crankcase like in pic 1.

My engine is M62 TU (vanos) and I was referring at the pipe that goes in both cylinder heads close to the exhaust manifold not straight into it. This pipe is aluminum too and has the valve which opens to let the forced air in the cylinder head. That's why I got confused , looks like is going in the crankcase but it goes actually in the cylinder head .

 

[joyism5]

if there was a fault and the air pump would have to malfunction in 2 ways to affect the engine. the pump would have to turn on, and the port on the ex manifold would have to open. if this happened (very unlikely), then your short term fuel trim might show up as lean, causing more fuel from the dme, causing too rich a fuel mixture and rough idle.

This actually did happen't to me and I had no rough idle . I run the car for several months like that. Air pump was fried . I have read that brushes in it goes bad pretty often. My pump was not serviceable.
The SES light came on and codes 0171 & 0174 system lean bank 1 and bank 2 showed up. Very close to those codes for the MAF when it goes bad 1171 & 1174 - Fuel Trim Adaptation Additive Bank 1& Bank 2 Malfunction.

 

[joyism5]

I don't recall to see that kind of hose on the V8. Maybe, on the secondary air pump. I see on your profile that you are driving an E46. This is the E38 section of the forum.....you might want to re-post on the E46 section, or there's even more activity on the E39 side of the house. Maybe you will get a faster answer. Indeed the straight 6 engine has those hoses for the crankcase ventilation system.

QUOTE :

I must say that I can hear intake hiss from the top of the engine (intake mani) roughly around about where the CCV / oil separator is (just forward of the DISA valve).

You are talking about the straight 6 engine for sure....

 

[joyism5]

Thank you I'm glad I could help. ..... then the air pump will be pulling fresh unmetered air and pushing it into the exhaust manifold, not the head.

The air pump does push fresh unmetered air into the cylinder head , (not the exhaust manifold). The exhaust ports of the cylinder head will direct the fresh air right on the exhaust valves. See in the attached picture the tiny hole where the exhaust valve has been removed.

 

[joyism5]

Yes I am but my post was directed at the OP,

I have not seen the "OP" in months , here on the forum. If you want a reply from him, try send him a PM.

This is all pretty general BMW stuff, or so it seems
thanks,
Carl

Indeed is general stuff for BMW. A little bit different design on the V8. Read this thread and you might find your answers : http://www.bimmerfest.com/forums/showthread.php?t=534005&highlight=

There are a lot of vacuum test for the straight 6 engine on the E39 section.

http://www.bimmerfest.com/forums/showthread.php?t=574452&highlight=

http://www.bimmerfest.com/forums/showthread.php?t=588505

Good Luck !:roundel:

 

[joyism5]

I think is the OSV. There is a plastic piece that connects the OSV to an elbow which usually breaks. Check around for OSV threads, I post somewhere some pictures with mein when it broke. Same symptoms.

 

[joyism5]

Yes. Read post #11 here: http://www.bimmerfest.com/forums/showthread.php?t=577207

 

[joyism5]

what's the best way to remove carbon deposits on valves in intake side....?

I would highly recommend not to use products(like Seafoam) that need to be applied through a vacuum line or straight to the intake. These might detach carb deposits in big chunks, which could fell between cylinder and cylinder walls, and will produce scoring on the walls. My personal experience is described in post #3 http://www.bimmerfest.com/forums/showthread.php?p=6391599#post6391599

Best way to safely clean them is using a gas additive, Ventil Sauber from Liqui Molly. It is used in Europe widely with great results. In USA is available online only (at least nobody heard about it in stores). I purchased it from autohausAZ.com.

 

[joyism5]

I never heard about something like this and I don't see it possible either.

 

[joyism5]

Hello. In my M52 is very low vacuum on hose connecting fuel presure regulator with CVV. Engine is working little rough. Hoses seems to be fine (only hose I didn't checked is CVV hose connected with oil dipstick, but I will do it soon), without vacuum leak, valve cover gasket also good, new, checked with auto-start fluid, CVV is new. But why is so slightly vacuum on hose connected to fuel presure reguletor? Almost no vacuum at all... Is this correct? FPR can operate with so slightly vacuum?

First, you will need to post in the 3 series (E36) section your questions. On this section (7 series) you might not receive as many answers because the M52 engine is not on the 7's. A smoke test will pin point better a vacuum leak, and a way to test the FPR is to remove the vacuum line from it, and apply vacuum to the FPR while the engine is idling. If is getting better while you are doing this, you might ned more vacuum on the line for the FPR. Smoke test for vacuum leak highly recommended.