Quote:
Originally Posted by Maestro
This specific lag was due to a software update BMW did, my car was affected at the time, two or three updates later this problem went away, but in between it caused other issues such as the waste gate rattle. My 07 has the latest software which was done probably 10 yrs ago and the car has been fine ever since.
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If you read my page about it closely, you will find that this a kind of simplification. What was really happening is:
1. BMW had a hardware problem with the wastegate rods elongating over time because they were too thin. This in turn caused a rattling noise at idle because the wastegates did not close fully with elongated rods.
2. BMW fixed a few cars by exchanging the hardware and found out about that issue. They figured it would be too costly to fix this in old already-build N54 cars and took two measures: a. for newer production cars, the rods were replaced by stronger parts (you can see that there is another part number for newer production cars). b. for older cars, they would open the wastegates in idle, thus eliminating the rattle, but with the side effect of turbo lag when having to close them at acceleration. You can see that there are different versions of the software for older and newer cars - actually, there are cars that do not even have the correct combination of hardware and software as the parts were switched out softly - mine was one of those, as it had the newer rods, but was not guaranteed by its production date to have them, so it got the laggy software). They documented that in the inital version of SIB111307 (until April 2009), you can find the exact wording on my page.
3. Many customers with older cars (such as me) complained about the lag after updates. Initially, BMW even said they had done nothing. After they were proven wrong, they said: "yes, but you cannot notice". After two of their own technicians "noticed", a few of the BMW Munich development engineers took MY car in to investigate the matter and had to accept that not only one actually COULD notice the difference, but they could also measure the delay, which was WAY too big at ~600ms before boosting.
4. In a second attempt, they reduced the lag a little, but I (and others) could still feel it, such that in the final version of the software, they decided to have a little (i.e. unnoticeable for many people) lag per default, but with an option in ISTA/P to switch to the old completely lag-free version. However, if you choose to have the option activated, they will not acknowledge rattling complaints any more. This was in the updated SIB111307 from May 2009.
Apart from some cars right in the beginning, they never changed wastegate rods again, because that actually means changing the whole wastegates at a high labor (plus parts) cost.
Quote:
Originally Posted by Maestro
You will need to know which software you car is running and I doubt it has the software which was affect since any maintenance done on the car since the issue showed up would have caused the dealer to update the software. My car was fine then they did this update as standard course of warranty and maintenance work and I immediately had the issue and was piss they update the software without my permission. I also doubt if you have full warranty car, this problem predates your car.
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The software is one thing, the state of the ISTA/P wastegate option is another and the real rod hardware is the third. However, I think that with the old rods, after another few years of rod elongation, you will get rattles either way and you will have to change the wastegaste. This should fix the problem permanently, because they will be of the stronger type.
The most desirable version is having the ISTA/P option set to "no lag" and getting new wastegates (or at least rods).
Quote:
Originally Posted by Maestro
I personally do not remember BMW ever acknowledging this was an issue, they just made a number of software updates to address various issues. Your car could have a lag issue for a number of reason now of which related to the software, Like all of us who dealt with this issue you just need to get the tech working on the car take it for drive and see what is happening.
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They certainly did not want to acknowledge this, but if you challenge my story, you will find that all proveable facts fit in. Their covering-up on this matter is well documented in their own paperwork (i.e. TIS history).
BTS: Take this with a grain of salt as this is old news, they may have changed to software or the availability of the option in the meantime (ISTA/P has been replaced by something else, I imagine).