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Originally Posted by 335i E92
Ok here's the situation... I have the rough idle exact same stumbling and rpm jumps up from 600rpm to 750rpm when the car is warm. I have spent the last 18 months trying to fix this issue that started imeediatley after changing the original plugs.
Firstly what we are all experience is NOT hardware related its 100% software. I've had 2 further sets of plugs, 6 injectors & 6 coils, full engine out and head off decarb over the last 18months an nothing has fixed the issue. This is 100% an adaptation issue.
Last week my local Indy brought a BMW main dealer master tech down to try to help the diagnosis. After listening to the symptoms and the fact that none of the above have fixed it along with the major clue that it happened straight after the plug change he has come up with what sounds like the fix.
I am booked in with him next week and was gonna start new thread to tell the masses but I'm that convinced it's going to fix he issue I'll spill the beans now and hopefully it'll be the end of this f@&king annoying rough Idle for good for us all!!
I've read every n54 rough idle post there is and have tried every adaptation available, even Mr5's BT cable reset which helped some didn't do shit for me.
However there is a reset that the master tech thinks is the fix. It's not available through the normal adaptation menu you have to actually cause a misfire on the engine by running it with a loose coil. As you will all know as bad as this rough idle is it's never thrown a code for any of us.
So basically by making the car throw a misfire code it will allow the tech to then run a misfire test module which will open up a menu that allows a particular stratification adaptation reset to be made. It's this adaptation that will allow the tech to change to stratisfied rather than harmoginous and fix this bull shit problem for good.
As I said im booked in next week and will start what I'm hoping will be a new thread to confirm the fix. In the mean time I would all ask to speak to your own master tech regarding the theory and get yourselves booked in.  |
I have the same trouble for a long time and without any code, but the trouble disappeared after my technician replaced a fuel pressure sensor.
Hope it useful for you.