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Discussion Starter · #1 · (Edited)
I noticed some engine oddities on my 540i/6 after a long road trip yesterday.

Symptoms:
-Idle slowly fluctuates between 1300 RPM smooth to 800 RPM rough.
-Seems like it takes much longer for the engine to slow down than normal (takes a second longer to get to idle from about 4k)
-When engine is slowing from 4k to idle, there is a loud howling noise coming from left cylinder head
-Large puff of smoke on startup after sitting overnight

To me this sounds like vacuum leak, although the howling noise from the cylinder head (which eerily sounds almost like a bad bearing) doesn't make much sense to me unless there is a breather there. Is there?

Any other thoughts? :dunno:
 

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Remove the oil filler cap while the engine is idling. Put you hand over the hole. If it really sucks on your hand, the CCV valve is bad. The normal vacuum is VERY low.

What you may be hearing is a vacuum leak at the cylinder head cover gasket, especially if they're original.
 

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Remove the oil filler cap while the engine is idling. Put you hand over the hole. If it really sucks on your hand, the CCV valve is bad. The normal vacuum is VERY low.

What you may be hearing is a vacuum leak at the cylinder head cover gasket, especially if they're original.
Hmm.. Interesting. Does the car have to be at operating temp or can this be donr on a cold start?
 

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Discussion Starter · #5 ·
After starting it up again today after having sat overnight, I noticed a large plume of smoke come out the exhaust but cleared up after 20 seconds. :tsk:

Also, listening to the exhaust, it definitely doesn't sound as smooth as usual. :thumbdwn:
 

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Didn't your scan tool give a text explanation of the code? It is "Fuel Trim Adaption Additive High (Bank 2)."

The fuel trim is being driven too rich on the left bank of the engine. The scan tool should measure and report the short-term fuel trim. This doesn't seem to have anything to do with your puff of smoke, but it may be that the extra fuel is washing oil off the cylinder wall, and it's burning, causing the smoke. Get it checked soon; if that's what's going on, those cylinders will wear fast with no oil in the walls.


ashto540: try it both ways; shouldn't matter


fleshins: should.
 

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Discussion Starter · #8 ·
Yes the scan tool said something along those lines. Today I let the car warm up completely, took it for a drive and viola, when I checked for vacuum on the dipstick tube, there was quite a bit, definitely beyond normal. Does this indicate a CCV for certain or can it be a couple things? And if I am doing the CCV what else should I do at 150k miles? :p
 

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if you want to do it on the cheap, you can, if you are very dexterous, replace the part of the CCV valve at the rear of the intake mainfold. However, at your mileage, consider pulling the intake manifold, and also replacing the intake gaskets.

If you go that far, consider replacing the valley pan cover.

Do you have the Bentley's service manual? Don't leave home w/o it.
 

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Discussion Starter · #10 ·
There seem to be conflicting posts about what part is to be replaced on the 540i in the case that it is the CCV. Is the CCV also called the oil separator? Or are there two parts of this system that could go bad?

http://forums.bimmerforums.com/forum/showthread.php?t=1064179&page=2

Some point out that the rear manifold cover goes bad and needs to be replaced (#2 here: http://www.realoem.com/bmw/showparts.do?model=DN53&mospid=47588&btnr=11_2281&hg=11&fg=40&hl=5).

Others say its the oil separator within the engine (#1 here: http://www.realoem.com/bmw/showparts.do?model=DN53&mospid=47588&btnr=11_2255&hg=11&fg=15).
 

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To be the CCV on a 540 you can test by putting your hand over the CCV at idle. There will be a noticibale vacumn pull and it will smoothen out and then get rough again when you remove your hand.
 

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It should not be leaking. It needs to be replaced
 

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The oil separator is on the front of the V8 engine, behind the lower chain cover. A pipe connects it to the CCV valve.
 
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