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... stuff deleted ...

They're mostly the same. AFAIK, the key difference is that the CCV itself looks different depending on the model year, and, the orange-and-black vacuum hose is not on the newer models.


For my M54, I simply placed a plastic bag over the oil filler hole:

The balloon test over the dipstick tube can be useful since if you find any pressure (i.e. inflating balloon) the CCV has failed.
OTOH, I think the plastic bag over the oil filler is not precise enough to measure a failure on the too much vacuum side. From my experience it pays to do the test with accuracy - and pay attention to the results :).

For instance, I sarted getting a bit of a rough idle. I tried the baggy test & passed. I assumed the CCV was OK. Then I measured crankcase vacuum accurately & found 9 inches of water column vacuum; well outside the 4 - 6 inches specified by BMW. I knew the CCV was going south, but took a chance and hoped it would be "OK enough" until warmer weather arrived. A few months later I had ~45 inches w.c. (!) vacuum and most of the symptoms listed for a failed CCV. And weather around 0 F.:(

Here is a link describing how to measure CCV operation accurately, cheaply and in about 10 minutes.
http://www.bimmerfest.com/forums/showpost.php?p=5990442&postcount=8

Since there have been so many questions on the topic of CCV operation and failure, here is a description of how I think the CCV operates using Bluebee's picture for reference.

The vent pipe, swirl labyrinth chamber and vent hose are always at the same pressure or vacuum - there is no valve or obstruction between them. The swirl labyrinth is the lower part of the CCV assy that the vent pipe & vent hose connect to. Further, they connect to the valve cover & crankcase without restriction and are at crankcase pressure/vacuum.

The connecting line and return pipe connect to the inlet manifold which has a vacuum of ~20 inches Hg (mercury) at idle; ~260 inches water column vacuum.

The portion of the CCV immediately beside the blue "CCV" label in Bluebee's picture is a vacuum regulator whose job it is to maintain 4 -6" w.c. vacuum in the swirl chamber.

When the engine starts, the labyrinth is at 0 vacuum (i.e. vacuum is less than 4" w.c.) & the orifice/valve in the regulator is open. The gases in the swirl chamber flow through the regulator into the connecting line (which is at high vacuum), on to the inlet manifold and through the engine. Soon the vacuum in the swirl chamber (also the crankcase to which it is connected) is sucked down to 4 - 6" w.c. vacuum and the orifice valve in the regulator closes.

The engine runs, more blowby gases from the combustion chamber enter the crankcase & raise the pressure (reduce vacuum) in the vent pipe & swirl chamber. The regulator opens again, allows manifold vacuum in the connecting line to suck them away until crankcase vacuum is back to 4 - 6" w.c. at which point the regulator closes again. And on it goes, cycling over and over.

As the blowby gas travels through the engine toward the CCV, it picks up microscopic droplets/mist of oil. We don't want this oil mist to go through the vacuum regulator, into the inlet manifold and be burned: high oil consumption and air pollution. Enter the swirl labyrinth; it causes oil droplets/mist in the blowby gases to stick to the wall of the labyrinth and drain down the vent hose into the dipstick tube and sump while the "cleaned" gases carry on through the regulator.

Now the problems that ocurr.
One
One of the CCV hoses ruptures with age and lets air into the swirl chamber. The regulator stays open in a losing battle to get down to 4" w.c. vacuum. Lots of air is sucked in through the hole, on to the inlet manifold and the ECU senses a vacuum leak - bad news.

Two
The regulator diaphram ruptures with age. Now it can't close the orifice and crankcase vacuum goes high. And/or the rupture is so large that we have enough of a vacuum leak the the ECU gets upset. Plus gaskets and seals are being pushed harder than designed may fail entirely.

Three
The CCV and hoses can get very cold in winter conidtions since they aren't heated or even insulated. Blowby gases have lots of water vapour as a product of combustion chemistry. If these gases get cold enough, the vapour condenses into water and we get sludge/mayo. The mayo/water can freeze and block the regulator orifice - either open or closed.
Stuck open - high vacuum resulting in damaged gaskets/seals (or at worst, hydrolock according to BMW)

EDIT 2 - had this sentence in the "stuck closed" paragraph:
Also, seals and gaskets can start leaking air into the crankcase - a vacuum leak according to the engine.

Stuck closed - high pressure resulting in oil leaks &/or blown out gaskets and seals. BMW warns pressure can get high enough to crack the valve cover.

Four
Again in cold weather, water condenses in the swirl chamber, sludges it up so it can no longer separate out the oil mist droplets. Then, the blowby with oil mist is routed straight to the vacuum regulator into the engine. High oil consumption and in the worst case, hydrolock.

Five
Again in cold weather, the oil draining down the vent hose toward the sump plugs up in the narrow channel of the dipstick tube. Perhaps with some mayo/sludge if the regulator isn't operating properly (see above) to get all the water vapour out of the swirl chamber fast enough before it condenses. The liquid oil backs up into the swirl chamber, oil gets sucked through the vacuum regulator into the engine. In the worse case, so much oil the engine hydrolocks.

Three, four & five being good reasons for installing the cold weather CCV kit & insulated hoses.

EDIT: six
I occurs that if the CCV fails as above, oil mist and water can condense out in the distribution piece that the connecting line attaches to on the way to the inlet manifolc. One could then replace the CCV but have enough sludge in the distribution piece that a slug of it is pulled into the inlet manifold after the repair when the CCV is perfect. Bad news.
Seems a good reason for at least checking the distribution piece when doing a CCV overhaul.

Regards
RDL
 

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Great explanation RDL, but I disagree with one part of your analysis. I think the diaphragm in the CCV is operated by intake manifold pressure rather than crankcase pressure.
... stuff deleted ...

The central tube connects to the regulating valve on the same side of the diagram as connecting line to the intake manifold. Inside the regulating valve the diaphragm works in opposition to a spring on the vacuum side of the diaphragm. So the diaphragm that closes off the passage of gasses from the cyclonic separator is exposed to vacuum from both the crankcase and the intake manifold.

I think the intake manifold vacuum will always be higher than the crankcase vacuum. So I think the diaphragm opens when the intake manifold vacuum is lowered(is closer to atmospheric pressure) as the throttle plate opens. This mode of operation would route the blowby gasses into the intake manifold when engine speed is high and air intake volume is high.
I agree with much of your description but I think you misunderstand how the pieces are working together as a system. Whether the diaphram port is open or closed depends on vacuum in the CCV , not inlet manifold vacuum.

1 When the engine is started the CCV valve chamber is at atmospheric pressure, no vacuum.
2 The spring is pushing the diaphram away from the center port that is connected to the inlet manifold. So, there is an open passage from the crankcase, through the CCV to the inlet manifold.
3 The open passage allows manifold vacuum (engine now running) to suck air & blowby gases from the swirl chamber through the center port, eventually creating a vacuum inside the regulating valve chamber (and crankcase too, of course)
4 Now the diaphram will be pushed against the spring by atmospheric (higher) pressure on the other side of the diaphram. As the vacuum increases, the diaphram moves closer & closer to the port connected to the inlet manifold.
5 Eventually the diaphram compresses the spring enough that it touches the vacuum port and seals it off. This stops the inlet manifold from sucking any more from the swirl chamber. For an instant the vacuum on the swirl chamber is constant.
6 Next, blowby getting past the piston rings enters the swirl chamber & moves up into the regulating valve chamber which reduces the vacuum.
7 With reduced vacuum, the spring is able to move the diaphram and open the vacuum port to the inlet manifold again
8 Vaccum inside the chamber is again sucked down - around & around it goes.

So the vacuum in the CCV, and crankcase, is generated by inlet manifold vacuum and controlled by the CCV regulating valve. As long as the CCV is operating correctly, inlet manifold vacuum will always be greater than CCV/crankcase vacuum.

The size (diameter) of the diaphram, its flexibility/stiffness, strength of the spring and the relative position of diaphram & center port are worked out by the designer so that diaphram is just touching, i.e. closing off, the center port at a vacuum of 10 to 15 millibar (4 to 6 inches water column) in the CCV.

If my explanation isn't clear, try Wikipedia and Google for "pressure regulator" or "welding regulator" for a better description. The function is a little different than the CCV since these are reducing a high pressure to a lower working pressure. But the principal is the same: a diaphram or piston pushing against a spring is opening & closing a port allowing the gases to flow from higher pressure to lower pressure.
 

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This is where we disagree. As I recall, the vacuum from the intake manifold and the crankcase are applied to the same side of the diaphragm. I do not remember seeing any part of the diaphragm that was molded to fit the tubes or any sort of special port. Just a diaphragm that moves against a spring to close off those two ports. Anyway, I'll take another looks at the diaphragm.

BTW, I was thinking about measuring the vacuum that must be applied to the CCV to close the diaphragm. Have you done that or do you have any advice about how to measure the vacuum required to close the diaphragm?
Yes, manifold vacuum and crankcase vacuum, or pressure, are applied to the same side of the diaphram. Except of course, manifold vacuum is blocked off when the diaphram moves far enough against the spring to touch the port connected to the inlet manifold. The port from the swirl chamber (crankcase) is never blocked. The diaphram isn't molded in a special shape to block off both ports. The flat center of the diaphram moves to touch or not touch (block or open) only the port in the center of the the regulator chamber which is connected to the inlet manifold.

This is the crucial point; crankcase vacuum (or pressure) is always present. Inlet manifold vacuum is "switched" on & off by the diaphram to control crankcase vacuum at 10 - 15 millibar.

Perhaps it will help to point out that when the diaphram opens the manifold vacuum port, crankcase vacuum does not instantaneously go to to full manifold vacuum. Rather it begins reducing crankcase pressure (increasing vacuum) as blowby gases are sucked into the inlet manifold. As crankcase vacuum approaches 10 - 15 millibar, the diaphram blocks the manifold port again, limiting crankcase vacuum.

So, the vacuum at which the diaphram closes off the inlet manifold port (i.e. center) is crankcase vacuum. See this thread for measurement methods
http://www.bimmerfest.com/forums/showthread.php?p=5989795#post5989795
Posts 7 & 8 suggest specific methods to measure this vacuum (or heaven forbid, pressure.:( )
 

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So the fuel pressure regulator in M52, connected to CCV is operated with crankcase vacuum?
I have an M54 so I'm not really familiar with your engine. I have though seen the pictures and diagrams of the air hose off the CCV running to the fuel pressure regulator.

When I first saw those pictures a couple of years ago, I was baffled at the design intent. I finally realized that "operated with crankcase vacuum" is technically accurate. But assuming the CCV is working properly it is really so close to atmospheric pressure that it makes no practical difference. The CCV regulates crankcase vacuum to less than 15 millibar, or EDIT 1.5% (not 0.15% in original post) different from atmospheric pressure.

I think the purpose of taking a reference pressure this way is to provide clean, filtered source of atmospheric pressure to the fuel pressure regulator without any chance of engine bay dirt, grit and grime fouling the sensitive parts of the small fuel pressure regulator. By comparision, the CCV is about 3 inches in diameter & much less sensitive to dirt. An awkward, klugey way to achieve the result in my opinion.

For the M54, BMW changed the design to take atmospheric reference pressure from the F fitting in the boot between the MAF and inlet manifold. That supply is kept clean by the engine air cleaner.
 

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... stuff deleted ...
Well, here are my data points:

  1. Original CCV (2002 model year)
  2. Warm dry weather (Silicon Valley)
  3. 8 inches of "crankcase" vacuum
  4. Vent pipe blow test showed no resistance
  5. No misfires
  6. Dipstick 'was' clogged solid - but it has been cleaned out
  7. No smoke whatsoever on exhaust (California smog tests are nearly perfect)
Given that conflicting information, I'm not sure WHAT the state of the CCV is in.

... stuff deleted ...
Two years ago, my car failed vacuum at 9 inches but had no symptoms at all: engine performance & idle qualtity were normal, no DTCs were present and no smoke from the tailpipe. A couple of months later the CCV system failed entirely. The engine then refused to idle, generated a raft of DTCs and lit up the CEL. Even after failure, I had no smoke. However, while replacing the entire CCV system I discovered a hole in the drain hose to the sump which created a large vacuum leak. The CCV valve body may have been functioning well enough to avoid driveability symptoms if the drain hose hadn't failed.

The 8 inch vacuum by your engine is a failure vs the specs of 4 - 6 inches. I conclude your CCV is failing but not so badly as to generate driveability symptoms. FWIW, if this were my car I'd continue to drive it but check vacuum regularly and have new CCV parts on hand. My logic being that although out of spec, the 8 inches of vacuum is still so weak that it is very unlikely to generate any other problems. And I don't know what I'd consider too much vacuum to tolerate; probably 12 inches (2 times upper spec) but that is an absolute double X triple WAG - not a SWAG since there is no science behind it. Or maybe I'd just wait for a nice day, replace the darn thing and be done with it.

I've never been able to understand the physics behind the blow for bubbles test. And I never got bubbling: not with 9 inches vacuum, not after my CCV failed entirely (but then it wouldn't with a hole in the drain hose) and not after CCV replacement with vacuum in spec.

Consider that with the vent hose disconnected from the valve cover and blowing into it, the chamber in the CCV is at atmospheric pressure or slightly above; certainly no vacuum. Therefore the CCV's diaphram and orifice will be wide open, ready to draw vacuum on the vent hose (and thus crankcase, if connected) as soon as the engine is started and inlet manifold vacuum is present. The air being blown into the vent hose will take the easy route to the inlet manifold rather than the path down into the sump to make bubbles. It seems to me that the only way to get bubbling would be for the diaphram to be failed closed or the distribution piece on the manifold to be clogged. In this case one would have +ve pressure with the engine running - a definite CCV failure. Yet a pass for a good CCV is supposed to be a little resistance and bubbling when blowing into the vent hose.
 

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I think some of the posts are incorrect. The vac hose effect is to reduce rail pressure at idle, by increasing bypass fuel flow. The cases where hose is tied to cvv may have additional effect to increase rail pressure at high rpm.
You're correct that my explanation is wrong or at very least incomplete. I checked TIS and the M52 engine does adjust fuel pressure depending inlet manifold vacuum. The M54 engine does not; it uses constant fuel pressure.

However, based on pictures and diagrams I've seen, the connection point on the CCV should be at crankcase vacuum, which is a constant 10 to 15 millibar vacuum. Essentially atmospheric; nothing like the 700 to 900 millibar inlet manifold vacuum seen during idle or over-run. So I can't explain the connection and response by the fuel pressure regulator.

I regret posting the mis-information on this question. I hope that someone else can provide an accurate explanation.
 

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My comments in red font

Interesting. Where did you check the vacuum from? I placed my clear hose over the dipstick.

I checked via the dipstick tube.

I have been meaning to doublecheck mine again just to make sure I didn't do it incorrectly so if there are other places to doublecheck the vacuum, that would be useful as a check of my procedure.

The only practical option that comes to mind is the oil filler. Either drill out a cap and fit a hose barb or a fabricate a flat plate with gasket surface and hose barb.

I had that exact problem just a few months ago:

I wound up a boatload of lean related codes too.
I think that what happened is that the CCV was failing vacuum but without any driveability problems. But the hose was still intact or only very slightly holed. When the hose failed for good a few months later, the vacuum leak caused all the driveability symptoms and DTCs. I wish that I had checked crankcase vacuum then; I'm almost certain that it would have been zero at that point. I suspect I could have gone a several more months (at least until warmer weather) without any problems if the drain hose had not failed.

- Does the ORDER of pcodes listed in an OBDII scanner actually matter?

A smoke test implicated the lower vent hose to the CCV, which, like yours, was holed (in fact, it was nearly broken in half!).
... image deleted ...

Even with that holed CCV hose, I also experienced no smoke. But there were tons of lean-misfire codes!

I don't disagree. Plus, the CCV is definitely original, so it's a decade old at this point in time.

Old doesn't necessarily mean defective. But with plastic ...

I understand that logic. That's what I did with my cooling system. The CCV, even for you guys, is a pain. So just imagine how time consuming it will be for me!

The CCV renewal is certainly a few hours but straightforward, not so difficult except for the infamous S tube to the CCV valve. Most people report spending a LOT of time on this connection. I did, IIRC over an hour before the light bulb came on. There is a solution,
http://www.bimmerfest.com/forums/showpost.php?p=5912837&postcount=77
see post 77 in Fudman's DIY.

Me neither. I don't personally think it tests anything. I said so in the aforementioned CCV test thread but I'll append your deduction also so as to add weight to the premise.
 

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On the M54 the FPR is on the fuel filter. It's connected to the "F" connector on the intake boot.

I don't understand why a FPR would need an atmospheric reference.
Recall the discussion of CCV operation earlier in this thread. One side of the diaphragm is exposed to crankcase pressure (or vacuum) and the "other side" to atmospheric pressure. The net force on the diaphragm working against the spring results in crankcase being maintained at 10-15 millibar (0.145 - 0.2175 psi) less than the pressure on the "other side" of the diaphragm. Since the pressure turns out to be less than atmospheric we call it vacuum.

Now imagine that the "other side" of the diaphragm is a sealed chamber with some pressure, let's say 2 psi higher than atmospheric pressure. The CCV would then maintain a crankcase pressure 10-15 millibar lower than the sealed chamber. Crankcase would be 1.9855 - 1.7825 psi pressure (not vacuum.) Alternatively, if the sealed chamber was at 2 psi vacuum, crankcase pressure would be 2.145 - 2.2175 psi vacuum (not pressure.)

By rearranging the relative positions of the spring, diaphragm and orifice plus providing a supply of high pressure liquid or gas, a regulator can be made to maintain an output pressure higher than the reference pressure. Presto, a fuel pressure regulator or welding regulator.

The point is that any pressure regulator operates to maintain a difference from a reference pressure; it doesn't "pick it out of thin air" so to speak. Since fuel pressure is specified as X psi higher than atmospheric, the regulator needs atmospheric pressure on one side of its mechanism.

As a matter of interest, not all pressure regulators use diaphragms; a piston concept is possble, as are other designs. But they all have a mechanism that compares pressures. I don't know which design is used in the fuel pressure regulator. Has anyone taken one apart?
 

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... stuff deleted ...

As I recall, in one type of FPR the return flow is blocked under low vacuum, such as acceleration. Another type of FPR actually increases return flow under high vacuum situations like idling. I suppose one could design a FPR to do both, but I've assumed that the FPR on the e39s are the second type that lower fuel rail pressure during high vacuum.

If I understand what you've written, you think that the FPRs on the e39s don't really use a vacuum source to move the diaphragm, only to vent area behind the diaphragm. Certainly the M54 FPR will not see a strong vacuum since it's connected upstream of the throttle. Assuming that the CCV is operating at crankcase vacuum, it would be insignificant for the M52, too.
A simple FPR will do both automatically, it wouldn't need two different types or a special, complex design. In both the cases you describe injector pressure changes in the same direction as the change in reference (manifold) pressure. This is normal response for a pressure regulator. You can work through the steps by considering vacuum to be -ve pressure and that blocking return increases injector pressure, increasing return flow reduces injector pressure.

I should clarify that vacuum doesn't move the diaphragm and the hose isn't simply a vent. Rather the balance of force from reference pressure on one side, force from fuel pressure on the other side, plus spring force determines the output pressure. The purpose of the air hose to FPR is to provide the reference pressure that the engine designer planned.

TIS describes that the M52 does change fuel pressure under different engine load conditions (high load / acceleration = low manifold vacuum, low load / idle = high vacuum) and apparently uses varying vacuum to the FPR to do so. However as I mentioned in the earlier post, I just can't work out how the tap off the CCV provides that changing vacuum to the FPR. :(

TIS does not say anything about the M54 varying fuel pressure with load.
 

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I can't find the description of the M52 FPR operation in the online version of the TIS. Are you looking at another version? However, that is exactly how I assumed the M52 FPR worked. And that is why I assumed that the vacuum port on the CCV was operating at manifold pressure.
Here is a portion of the TIS procedure for checking fuel pressure on an M52. You will see it specifies a change of 0.4 to 0.7 bar (6 to 10.5 psi) between idle and full load condition.

The corresponding page for an M54 notes a single test value. No mention of differing values between engine load conditions.

This is the 12/2007 TIS data.
 

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I received a PM asking for help with "distribution piece" noted in post 23. I couldn't attach an image in my reply PM. So here it is.

I pinched this image from another post & marked it up with the red text. The yellow text appeared in the original and isn't relevant in this instance.

 

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What if the O-ring is bad on the oil dipstick what is still make the glove blow up

Sent from my LGMS210 using Bimmerfest mobile app
Assuming everything else is working properly, a bad O-ring would leak air into the crankcase since the CCV maintains a vacuum of 4-6 inch water column. The engine would see this as a vacuum leak, just like any other.

Or are you asking if both the CCV and the O-ring are bad?
If the CCV failure mode is to create pressure rather than vacuum (i.e. blow up the glove) then air would leak out at the faulty O-ring and could carry oil droplets with it, making a mess around the tube.
 
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