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Seek to understand,^Value
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Discussion Starter · #21 ·
Well there is a thread for chasing vacuum leaks
Actually that thread is for diagnosing misfires ... many of which do happen to be vacuum leaks. :)

That thread was written simply by reading scores of misfire threads, and putting into that one canonical thread all the potential culprits. Now we need to expand it to include better diagnostics for 'each' culprit.

It's not anywhere as good as it should be (I should know! :) ). So far, it mostly just 'identifies' problem areas; but the 'diagnostic' part for each problem area is greatly lacking (and needs to be improved).

For instance, here is a specific diagnostic for suction out of the oil filler cap that I just ran today while I was spraying Kalifornia carb cleaner all over my engine to detect vacuum leaks:


See post #1
That post is fantastic, but it's for the CCV specifically. I have no indication that my CCV, in and of itself, is malfunctioning (yet).

If the CCV drain hose has a hole, the CCV will open wide in a vain attempt to pull a small vacuum on the crankcase
I took another look (and pictures in daylight) of the 'mouse-eaten' CCV insulation.


I ran the engine and sprayed carb cleaner and then Brakleen (which dried up much quicker so I assume it's vastly more volatile ... which is what you want).

I looked & listened (for rpm changes) closely. I do not think the integrity of the plastic CCV drainage pipe is breached.
 

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Older than old school
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Bluebee, are you getting a lot of suction at the oil filler cap, or just moderate? In another thread I read a post recently that a lot of suction indicates a failure of a hose attached to the CCV, resulting in a high vacuum condition under the valve cover. This would be another avenue for air to get into the intake system without going past the MAF, and it could result in too lean a mixture. For the life of me, I can't find the thread, though. It was just in the last couple of days, I think.

I just tested my car by cracking open the oil filler cap and got noticeable, but not powerful, suction.
 

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You should have 3"-6" of vacuum pressure, as measured by a manometer, at the oil fill cap or the dipstick tube. However, this is not a foolproof means of determining CCV function. Gtxragtop checked mine a few years back and it measured fine. I went ahead and changed my CCV after blowing a huge cloud of black smoke accelerating onto the highway. Other than excess oil consumption and some mayo, I had no other symptoms. Since then, oil consumption is significantly reduced (from a qt every 1.5K to every 5k), the mayo is gone and no smoke.
 

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Actually that thread is for diagnosing misfires ... many of which do happen to be vacuum leaks. :)

... stuff deleted ...

For instance, here is a specific diagnostic for suction out of the oil filler cap that I just ran today while I was spraying Kalifornia carb cleaner all over my engine to detect vacuum leaks:


That post is fantastic, but it's for the CCV specifically. I have no indication that my CCV, in and of itself, is malfunctioning (yet).

... stuff deleted ...

I do not think the integrity of the plastic CCV drainage pipe is breached.
I would have sworn I've seen a vacuum leak thread. Perhaps by Poolman then? If so, my apologies to both of you for faulty attribution. :(

By the look of that picture I think your CCV is suspect; too much vacuum, it seems to me. The correct value is so weak that a first impression putting a palm over the oil filler or finger on the dipstick tube is that there is no vacuum. When I first checked mine after a new CCV, the air was blue - I was sure that something was wrong. But then the manometer said 4 1/2 inches water column :)
I recommend you rig up a manometer & look for 4 to 6 inches water column at idle.

BTW, a point of clarification: the "mouse eaten" tube is not the drain tube. The CCV drain tube runs beneath the throttle body into the dipstick tube down by the sump. It is more flexible rubbery rather than hard plastic.

Regards
RDL
 

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Discussion Starter · #25 ·
I just tested my car by cracking open the oil filler cap and got noticeable, but not powerful, suction.
Wow. How do we, independently, compare a 'lot' versus 'moderate' suction?

I'd say there is a teeny tiny bit of suction.

In fact, just enough suction to suck a very thin plastic film downward slightly. In the photo above, I 'tapped' the plastic slightly with my finger so that it would show up better in the bright picture; so the actual suction is less than what appears in the photo (poetic license exercised & admitted).

The engine also noticeably changed RPM when I removed the oil filler cap. I really don't think the ccv pipe is breached ... however, I can not at all explain the 'teeth marks' on the black hard plastic pipe either.

BTW, I did spray Brakleen on all things that 'looked' like they might be part of the vacuum apparatus. Only at or near the deeply ensconced throttle body valve did even an almost imperceptible change in RPM occur (if that).

 

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I realize my terminology was vague and subjective, but I didn't really have any way to quantify it. However, I think the subsequent posts by Fudman and rdl have clarified it pretty well. Plus, judging by your description of what you did for illustrative purposes, that's not the issue. What kind of gas mileage are you getting? (Not to incite another controversy.) Has it dropped noticeably since you've had the problem?

Nice action shot of brake cleaner spraying, by the way.
 

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Bluebee, I just had another thought. You might need to replace your gas cap to solve this. Here's an interesting article from Popular Mechanics that might explain why. Pertinent quote:

As car manufacturers started to understand emissions better, the number of vacuum lines diminished-but that didn't last long. The EPA started to require that leaking gasoline fumes be reduced to virtually zero, and the EVAP system on every current car is controlled largely by-you guessed it-engine vacuum. When the car is turned off, the system captures fuel vapor in a charcoal canister, then parses the vapors back to the running engine through-you guessed it again-a network of vacuum hoses.
 

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Discussion Starter · #28 · (Edited)
The mouse-chewed hose is apparently, as stated, not a 'drain' hose but a 'return hose' (aka "top hose") for the CCV.

Here is a picture (the front of the engine is to the right) from here:
- M54 CCV top hose



Another picture showing the return hose & location of the CCV is also there:
- ICV, CCV, Vanos or all three?!



Realoem lists it as #7, "Return pipe" (PN: 11617504536, $33.87):



BTW, I don't have oil consumption, smoky exhaust, oil sludge, or, to my knowledge, excessive vacuum (?).

But, I do have a vacuum leak (obviously, from the codes); and there 'is' weird damage to the ccv insulation.

Tomorrow, I'll take a more accurate picture of the vacuum and I'll look for a balloon if I can find one lying around to try cn90's trick:
- E39 (1997 - 2003) > Cute little trick to diagnose blocked CCV

You should have 3"-6" of vacuum pressure, as measured by a manometer, at the oil fill cap or the dipstick tube
I googled for the manometer and found this reference ...
- How to test CCV?

Which suggests this particular manometer:
- Dwyer Slack-Tube Manometer, BMW tool part number 99000001410 (aka BMW PN: 99 00 0 001 410).

The complete kit (including oil-filler-cap-interface) is apparently available from DDM Tuning:
- Genuine OEM BMW Part # 99000001410 C/C VENT VAL TOOL $196.63

But, just the manometer (without the BMW interface components) is available on the net:


There is apparently a service bulletin on how to use it to test the CCV:
refer to service information bulletin number 04 08 98 for further information regarding the slack tube manometer tool ... With all electrical consumers and the air conditioning switched off and engine at operating temperature the reading should indicate from 3.0 - 6.0 inches of water at idle ... A higher than normal crankcase vacuum will cause the crankshaft seals to leak outside air into the crankcase during engine operation. A whistling or howling noise is usually heard coming from the seal areas (front or rear) at idle when this occurs
Regarding the whistling noise, I'll check tomorrow since I didn't realize I should look for that. Here, are symptoms of a bad CCV according to:
- Crankcase Ventilation System Check For 1994-2007 BMW Engines (1) (2) (3) (4)
[Note: These separate references all have the same text so I ordered them in best to worst presentation format.]

A properly functioning pressure control valve is designed to maintain a slight vacuum (approx. 10-15 mbar) in the crankcase ... A malfunctioning crankcase ventilation valve may cause the following complaints:

  • Engine runs rough
  • Whistling noise from the crankcase ventilation valve
  • Check Engine Light on
    • possible DM faults stored
    • misfire all cylinders
    • oxygen sensor/mixture faults,
    • etc.
I searched for how to test the CCV, and went back 5 pages into the Bimmerfest record. There was no thread specifically titled as a CCV test page, so, I'll open one up so that we can explore this topic well enough for others to follow easily in our footsteps.

EDIT: Here is the thread opened up:
- How to test the BMW E39 pressure-controlled crankcase ventilation system (CCV)?

 

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Discussion Starter · #29 ·

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Right--it's possible that with your gas cap off, the extreme vacuum from descending a 9% grade with the throttle closed would be enough to suck air in through the evaporative emission system and produce a lean condition that would register a fault code.
 

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Discussion Starter · #31 · (Edited)
What kind of gas mileage are you getting?
I have no idea! I never check my gas mileage.

Besides, I use the verboten low-octane-rated stuff from Costco (I'm ducking already!)
- Engine fuel, i.e., gasoline & octane (1) & "The Gasoline FAQ" & top-tier gas stations (1)

Next fuel fillup, I'll keep records to test the gas mileage (taking into account sig figs):
- What is the tolerance (i.e., accuracy) of our typical miles per gallon (MPG) calculations (1)

Nice action shot of brake cleaner spraying, by the way.
Heh heh. Thanks. It's a balancing act, one hand on the SLR up close to my face (so I can't see except through the lens) and the other hand spraying in the 'general direction' to where I 'intended' to point it (while the Brakleen splatters all over the camera lens like in a bad dinosaur movie).

Here's a shot of the Brakleen aimed directly at the 'mouse-chewed' portion of the CCV return pipe which connects on one end to the "intake manifold" and on the other end to the "connecting line" (which itself, connects to the intake manifold and to the CCV).

Note: I think the realoem diagram has this insulated CCV "return pipe" positioned backward. The "return pipe" seems to connect in the rear of the engine (to the right in this picture) to the intake manifold; and it seems to connect in the front of the engine (to the left in this picture) to the CCV "connecting line" (which itself connects to the intake manifold on its upper end, and to the CCV itself on its lower end).



However, detailed debugging of the CCV is probably off topic for a spark plug DIY, I opened a separate thread (after searching for an existing thread of the same topic) specifically for testing the CCV over here:
- How to test the BMW E39 pressure-controlled crankcase ventilation system (CCV)?

BTW, Rajaie apparently said the following regarding testing the CCV vacuum with a plastic baggy:
- E39 (1997 - 2003) > Cute little trick to diagnose blocked CCV system... (see post #4)

"The crankcase vent valve and 4 associate hoses fail and cause a vacuum leak. The valve gets stuck open and the hoses crack. These last 70-120k miles and usually fail 80-90k miles. Here are a couple diagnoses.
At warm idle, place a small plastic freezer storage bag on its side over the oil fill hole. If the bag sits on top or gets slightly sucked in, ~1", the valve is good. If the bag gets significantly sucked in the hole the valve is stuck open and bad. With the engine off and cold, carefully remove the hose at the valve cover front corner. Blow hard into the hole. You should hear oil bubbling in the oil pan. If you don't hear the bubbling the top or bottom hose is likely cracked. The bottom hose often breaks just below the valve connection. There can also be cracks in the other two hoses."
 

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Discussion Starter · #32 ·
BTW, while researching the CCV, I found an excellent picture of the 'underside' of the mouse-eaten CCV "return pipe" over here:
- CCV Replacement FYI - M54

 

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Discussion Starter · #33 ·
That photo above sparked my imagination in that I can now come up with a tentative hypothesis of WHAT caused that semi-circular shaped 'mouse-eaten' bite out of the CCV "return pipe" foam insulation.

My hypothesis:
- Someone flipped up the "air distribution piece" much as Jason5driver did here.
- In doing so, they 'pinched' the CCV return pipe between one of those prongs sticking out of the air distribution piece and that circular tube sticking up out of what appears to be the intake manifold.

Does that hypothesis sound potentially reasonable for the cause of a semicircular bite out of the M54 CCV return pipe foam insulation?

 

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Sure does--especially if, in typical BMW fashion, the rubber has oxidized and become friable. It seems to crumble at the slightest provocation.
 

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Discussion Starter · #35 ·
I was updating the misfire diagnostic thread today with new information:
- General diagnostic procedure for a single or multi-cylinder E39 intermittent misfire?

Where it says:
Swap the spark plug boots between adjacent cylinders
  • If the misfire moves, replace the spark plug boot
Now that I've replaced my spark plugs, I have a better idea what is there, and, well, uh, um ... I don't remember 'no spark plug boot.

The coil attached directly to the spark plug, IIRC.

But, maybe the coil was two pieces?

Is it that the bottom half of the coil (see below to the left in the picture), is a removable "spark plug boot"?

 

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Discussion Starter · #36 ·
As for the unanswered question about the separate "spark plug boot" (aka "spark plug socket"), & bearing in mind that Realoem is sometimes wrong, I opened a separate thread over here:
- Does the M54 coil have a separate spark plug boot (or not)?



I did a retest using the "balloon" method suggested by cn90.
Results appear to be:

  • Oil filler cap has slight (about 1/2 inch) suction
    • Also the oil filler tube "gurgles" when I remove the oil filler cap (what does that indicate)?
  • Dipstick guide tube has neither vacuum nor pressure
    • Suction seemed barely minimal or even non existent
    • Pressure seemed non existent
Here is a pic, without any enhancements, of the oil filler vacuum test:


And, here's that same test on the dipstick guide tube:


Lastly, here's my attempt at rubber banding a nitrile glove onto the dipstick guide tube (sorry cn90, I didn't have any balloons handy):
 

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Discussion Starter · #39 ·

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Discussion Starter · #40 · (Edited)
For the record, a set of discussions today about the $1,200 savings at 100K miles simply by using 87 AKI over 91 AKI fuel prompted me to look again at my spark plugs shown above for evidence of ping-related damage:
- What factors in cost differences between using regular vs premium fuels on our E39s?

Those original spark plugs above were removed after about 70K miles driven using Costco 87 AKI fuel.

Given those plugs had about 30K miles presumably on 91 AKI with the remainder on 87 AKI Costco fuel ...

Do you see anything negative about those spark plugs that is unusual for 100K miles?
 
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