WHERE does the CCV vacuum source port go for the E39 CCV valves that are not plugged?

Originally Posted by bluebee

....Since picture sites are ephemeral, I've taken the liberty to shrink to 640x480 & then upload the original picture (showing the M54 CCV endcap in situ) ...

I didn't notice the CCV end cap until I zoomed in on the photo. I've added labels for that cap, the SAP one-way valve, and the SJP for clarity.

Note also that this photo shows the older style tube that connects the CCV to the dipstick tube. The newer style has a 45 degree bend instead of the 90 degree bend in this photo.

Originally Posted by Steve530

I've added labels for that cap, the SAP one-way valve, and the SJP for clarity.

That addition makes the photo triply useful, for example for the SAP/SAS thread:
- How the secondary air system (SAS) and secondary air pump (SAP) and air valve, check valve, & electrical valve operate (1)

Originally Posted by bluebee

That addition makes the photo triply useful, for example for the SAP/SAS thread:
- How the secondary air system (SAS) and secondary air pump (SAP) and air valve, check valve, & electrical valve operate (1)

Note I had incorrectly labelled the fuel tank breather valve as the suction jet pump in post #26. I edited the photo to fix this mistake. Sorry for any confusion this might have created.

For the record, a similar question was asked today:
- E39 (1997 - 2003) > What is this hose for on the ccv is it important?

Originally Posted by e39munoz

what is hose number 6 used for?
i changed the ccv a week ago and i dont remember connecting that hose

Originally Posted by Steve530

So it seems likely that the nipple was indeed a vacuum source for a fuel pressure regulator. At high engine speed, a vacuum would be applied to the FPR to increase fuel flow. At idle, the high manifold pressure the closes CCV diaphragm and no vacuum would be applied to the FPR through the line connected to the nipple.

BB this thread is indeed very interesting.

I have an additional comment on the above quote from Steve530's post and that is that the vacuum for the FPF on the M52 motor and all other FPRs that I am familiar with works in exactly the opposite way that Steve530 describes.

When the engine is at idle (& at deceleration) it produces the greatest vacuum. This vacuum applied to the FPR reduces the fuel pressure at idle-less fuel is needed at idle. I know this for sure because when I installed a supercharger kit on my 2000 528iT (M52TU), I kept getting 1088 & 1089 fuel control fault codes-the short term fuel trim was in the -24 to -27 range on both banks when the engine was at idle. The instructions from the SC company had me disconnect the L shaped connector from the CVV and route it to the intake tube of the SC, sealing off the connection for that tube at the intake manifold. This removed the vacuum source from the CVV and hence from the FPR. I finally connected the vacuum hose from the FPR to an unused 3.5mm vacuum nipple on the back of the intake manifold-the STFT values went to -2 to -3.5 (normal) and no more fuel control fault codes. So the vacuum reduced the fuel pressure at idle. Also when the throttle is opened the vacuum is decreased & fuel pressure is increased when engine power needs to be increased.

BTW your vacuum port #9 above with the cracked cap is connected, in my car, to a vacuum line that supplies vacuum to the brake booster. Also the FPR in the M52 (single Vanos) is located on the fuel rail. On the M52TU it is relocated under the car, just in front of the fuel filter, under the driver's seat. On the M54 the FPR is integrated into the fuel filter located under the car, under the driver's seat.

Good comments, John. My analysis may be totally wrong. Here's some of my observations.

The crankcase vacuum with a properly operating CCV is reported to be 3 to 6 inches of water at idle. I measured the vacuum at one of the intake manifold nipples at 20 inches of mercury at idle. That's a lot of difference in vacuum.

Hose #3 connects the upper part of the CCV (the actual valve) to the vacuum of the intake manifold. Hoses #2 and #4 connect the lower part of the CCV (the oil separator) to the crankcase. That nipple to which the vacuum tube going to the FPR connects is below the diaphragm in the CCV. So my assumption is that the vacuum supplied to the FPR follows the operation of the diaphragm.

I agree that the every FPR I've seen operates by lowering fuel pressure as the vacuum supplied becomes more negative.

But it's also a fact that PCV valves have reduced flow at idle and higher flow at open throttle conditions. The top part of the CCV is essentially a PCV valve.

There appears to be ample vacuum to suck the oil out of the crankcase if the lower part of the CCV operates at intake manifold pressure. So the question is how is the intake manifold vacuum supplied to the FPR through the nipple on the CCV without creating so much vacuum in the oil separtator that the oil is pulled into the manifold?


EDIT: BTW, can you tell if the vacuum hose attached to the large vacuum port on the back of the manifold goes to the brake booster or the sucking jet pump?

Steve, I want to thank you for your insightful description of the workings of the CVV. There is no doubt in my mind about the workings of the lower part of the valve-the oil separator function is clear after your explanation. It almost seems like the top half of the valve was originally designed to supply vacuum at deceleration and idle to the FPR while it sucks blowby gasses into the intake at off idle engine speeds. When there is a strong intake manifold vacuum and the diaphragm closes, the vacuum is directed to the nipple which isn't even used by the M54. Off idle, the diaphragm opens and the blowby gasses get sucked into the intake because there is such a large volume of air moving through the intake. This reduced vacuum is not enough to suck the oil out of the sump, but, if with age, the diaphragm begins to fail, oil get sucked up the dipstick tube-at first increased oil consumption, then clouds of blue smoke and finally, perhaps hydrolock, if the vehicle owner is asleep. Hahaha! Not really!

So why did the BMW engineers design such a complicated and problematic system for PCV function. My 96 Ford Ranger pickup 4.0 has a $15 PCV valve that seems to take care of things just fine. My 85 Euro M6 has a tube on the dipstick that ends in a tiny orifice. A hose leads from the orifice
to a vacuum port on the intake manifold-PCV function handled. Do you think, perhaps, the German engineers of today are just a little compulsive???

Thanks, John.

Your post got me thinking about the CCV once again. The vacuum port between the oil separator and the valve probably is operating at intake manifold vacuum since it controls the FPR on your car.

I cut a quarter section through the oil separator and found there is more structure in the cone than I had thought. There are a series of vanes inside the cone that direct the flow of gases. Also the tube that connects the valve to the oil separator goes all of the way through the oil separator to the hose that drains to the dipstick. There must be some opening in the tube that allows the oil to enter the drain hose, but I have not yet found that.

Originally Posted by Steve530

There must be some opening in the tube that allows the oil to enter the drain hose, but I have not yet found that.

Looks like nobody knows the answer to that question, least of all me.

But, I came here just now to cross link this post today to here, for the record:
> E39 (1997 - 2003) > Cute little trick to diagnose blocked CCV system...

Originally Posted by Zakov

So the fuel pressure regulator in M52, connected to CCV is operated with crankcase vacuum?

Originally Posted by rdl

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 if 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 0.15% 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.

The information in this thread today belongs here to keep the discussion together:

Originally Posted by ztom

The vac hose effect is to reduce rail pressure at idle, by increasing bypass fuel flow. The cases where hose is tied to the cvv may have an additional effect to increase the rail pressure at high rpm.

Originally Posted by rdl

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.

Originally Posted by rdl

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

Hi not sure if it the same as mine ccv i have a 1998 e39 . mine is under the rocker cover down by the throttle body .

It makes me feel good when, after all this work by everyone, a question is answered here, in the forum, well before someone even thinks to ask it.

Happened just now, for example, for this vacuum port:
> E39 (1997 - 2003) > Oil Separator Small Vacuum Hose

Originally Posted by Dnormand

I purchased a CCV kit for my 2001 BMW 525i. Installing it, for a moderately experienced DIYer, was a bit frustrating. I was able to find 3 video segments on Youtube that did a good job of providing step by step (look up M54 Crankcase ventilation). I have 2 issues for the forum - one a question and the other a comment/suggestion.

Question:
The new oil separator(OS) has a small port that was unplugged upon receiving it. Official BMW records say that port is "required" for my model year car. My old OS is not have it so I am thinking just plug it up. What should I do and if needed where does it bloody connect to?

Comment:
In order to connect the breather hose (valve cover to OS) I used a heat gun to soften the OS side due to it being very stiff. I actually broke the first OS trying to connect this one. (urrrrgggg!) Sometimes these aftermarket kits require a little finagling right?

Responses appreciated. Here is what I am talking about.

I'm hoping this will be relevant to this thread.

Cliff Notes:


My car is a '00 (11/99) 528iT with the M52TU and a slushbox (A5S360R / A5S390R, I think). My hunt for a wiring fault causing P0335 and P0727 has [d]evolved into the following project:

- Adapter Lead (12514592703) for CKP: Connects to #8 here
- PS Reservoir and the low-pressure hoses
- Oil Filter Housing Gasket
- Intake Manifold Gasket
- CCV and associated tubes
- ICV cleaning
- Dipstick cleaning/redesign (from this thread
- Cleaning out years of gunk that have dripped and coated the block/undercarraige

I'm finding that a lot of my time is being spent rooting around for the safest way to disconnect various wires and hoses. I've never thought of myself as particularly ham-fisted, but I'll be porked if a lot of these connectors don't break if you look at them funny.

Right now, I'm trying to determine the best way to disconnect the intake manifold vacuum port, (#4. Do I just pry it gently? From the etk, it almost looks threaded. I didn't want to remove any hose clamps unless I had to, but maybe that's the best way?

Screw it. I ended up cutting the clamp and the tip of the hose off. An hour wasted for that stupid thing, argh.

I need to expand my nuts/bolts/washers collection. If I'd had the right size washer, I would have cut a slot in it to use as a fork to separate the hose and the fitting.

Santa's getting an addendum to my list this year:

Over here, Doru supplied a great post explaining the related vacuum for the V8:
> E39 (1997 - 2003) > How to test, clean, & redesign the original BMW dipstick guide tube (CCV vent clogs!)

Originally Posted by doru

Not on the v8. the dipstick goes straight into the sump without any other "attachments" (read tubes).



V8 CCV design is actually a cyclone, a different design than i6. It has no diaphragm.



The vacuum is created different.



Also, if ingestion occurs, the cylinder bank that gets it should be all disabled, not only 3 cylinders. Why is the 4th healthy?