This time, a story regarding E60 with the “dinosaur” is well known to me. As a difference from older vehicles, this car has MS45 engine management, which has not evolved since MS43. Still narrowband probes in the exhaust – all like in classical M series engine.

The DME error message contained error messages regarding lean fuel mixture in both banks; sometimes, EML (Check engine symbol) lighted up in KOMBI.
Local ”specialist” volunteered himself to solve the problems. He called and informed me that he had found the problem: the DISA valve was to blame! 100%! At the same time, the specialist ordered a new DISA valve; after several days, it was replaced and… And then strange things started to happen… The specialist informed the customer that DME is not warming up the Lambda probes after repair – that is strange. But, not finding the cause of the problem, the specialist returned the car to the owner, saying, “Well, let’s see”.
It didn’t take long to see – in the next morning, EML again proudly lighted up in the KOMBI. Connecting INPA, I detected:
a. Offset adaptations of both banks are close to the maximum (+0.9 .. 1.1 mg/stk);
b. short term corrections – close to the maximum (reaches +17 .. 25 %);
c. in the DME error memory error messages for lean mixture in both banks, short-term corrections have reached +27% in the attributes.

The situation is COMPLETELY identical as it was before replacing the valve! How so? Obviously, the problem was somewhere else!
It turned out that the specialist hadn’t performed the smoke test for reasons incomprehensible to me. Directly after replacing the valve, he has deleted individual adaptations of the Lambda probes, after which the DME switched to the “open-loop mode” for non-understandable reasons. So – also, the impact of the “repair” was not evaluated! The engine was not readapted; the customer received the car working in an open-loop! This “little” issue could turn out into significant losses! Why?
If DME works in Open-loop, the fuel mixture is not controlled. Considering that the engine had problems with the fuel mixture without control (and significant correction), the fuel mixture is incorrect. Such a fuel mixture can very swiftly damage:
a. CO catalytic converters;
b. Lambda probes.
The cars of the current year of manufacture have quite strict emission limits to pass the TI (0.3/0.2% CO and 200ppm HC), which means – if DME would not start to work in closed-loop mode very soon, EML would be activated due to reduced performance of the CO catalytic converters, and, to pass TI, the owner would need to spend some EUR 1000. Isn’t it wonderful? Unjustified repair for EUR 200 and potential problems for 5x more considerable amount! The next version of the specialist – well, the valve cover/CCV and the pipes connected with it, should be replaced. The specialist is such a guru that he was able to make a diagnosis remotely, not even seeing the car.
Note: not readapting the engine after deleting the adaptations (and/or repair works) – is a gross infringement of the BMW repair procedure.
Unfortunately, the specialist did not even offer an immediate solution to the problem but also behaved very incorrectly – he announced: given that I have allowed publishing the nasty story, there will be no repair of “flows”. Yes, dishonest specialists tend to behave so – all possible tools are used. The owners of the vehicles are “blackmailed” in such ways – as threatening to inform other service specialists that the customer is “difficult” or a “debtor” or – “if you tell someone, I will not fix my mistakes”. Of course, most customers choose to solve the problems “secretly”, understanding that their situation is only getting worse. Keeping in mind that there are no contracts or agreed commitments, they are under the complete influence of the “specialists”.
I choose a different path.
New error messages regarding lean fuel mixture in the DME error message memory. As we see from the attributes:

a. the error messages are recorded in idle;

b. STFT reached the mark of +22%

Live data confirm that:

a. Offset type LTFT of both banks have reached max values: +1.1 mg/stk;
b. STFT is strongly increased for both banks and reaches +17 .. 22%.

So the total increase for the fuel is around 50%! It is a severe problem!
My verdict was the following – the air is being sucked into the intake manifold. I will shortly mention possible alternative versions and reasons why they can be dismissed:
a. reduced fuel pressure. Ignored, because we see that the Multiple type LTFT are correct (in the range of 2 .. 5%), which means – in case of increased RPM and/or even by slight load mode, the fuel mixture is correct. I checked it also to be sure.

In the image: fuel mixture STFT in conditions of 2500RPM:

Yes, in this mode, STFT is close to the 0: the situation is perfect!
b. problems with a reading of the air mass meter. Version dismissed because – everything is fine in 97% of all work range, and, in addition, DME has managed to successfully trim the Offset value of the air mass meter (DME does it whenever the measuring element of the air mass measures has warmed up and ignition is on, but RPM = 0). It is hard to imagine the situation – Offset data and data of almost all segments are correct, but in some %, the sensor is “lying”.
Within minutes it’s become clear that there is one plug missing; here is the source of excess air suction. Mechanic managed to make an improvised plug, and it was installed. I started the car, and… Here is live data:

in both banks, STFT from +17 .. 22% has dropped to -4 .. -10%! So, the air intake has been reduced by around 30% points!

When the car was left to run idle for 5+ minutes, DME started to rewrite Offset type LTFT. Here, from +1.1mg/stk, they became +0.4/0.5mg/stk!

Here, the technical openings intended for some additional equipment are marked in the image.

And here, in the list of spare parts, it is clearly visible: there should be a “cap” (plug). 7mm cover was… either it was lost, or some “specialist” has decided that it is “not necessary”. Needles to say, this air intake could be perfectly seen during the smoke test!
Here, the fuel mixture is correct! The cause of the problem has been found! But 0.5mg/stk means that relatively slight air intake still is active.

Visual inspection clearly shows that the oil leaks on the top of the crankcase cover, in the area of the oil feeler. It is clear that the Y type tube and O ring are leaking (spare part No.12). Logically, if the oil gets “out” with the same success, the air gets “in” in the inlet manifold! Here, one more place of the oil suction can be seen with an “unarmed eye”.
So, this entry clearly shows that the qualification of the specialist and correctly diagnosed problem are very significant, as the live data analysis before and after repair. Stay away from the “specialists”, to whom everything is clear from the symptoms or offer to exchange all in a row.
P.S. addition. Here is how the Y tube looked after dismantling:

Offset adaptations after repair:

Repair successfully completed!