Hi,

Had my 545i for a few months now and loving it, not been plain sailing as I have to replace the coil packs due to a misfire...all was well until.....

Have noticed a few symptoms that have got worse the last few weeks

- When cold the engine can have a rough idle which lasts a minute (was like this just before the coil pack broke down)
- The car emits steam before it gets warm, not thought much of this as it has been cold here until recently, well its 15 degrees outside today and I still get steam vapor from the exhaust
- When cold I hear a tapping from the front of the engine, clears up quite quickly but was quite noisy today, noise was coming directly from underneath the filler cap, I released pressure on the cap and the noise went much quieter...very odd.

Checked all the usual things, no loss of oil or coolant that I have noticed

Any ideas welcome, looks like I may have to take it to the dealer soon

 

Hmmm, just did a search on the rough idle, did not realize it was so common on the V8's

I have read quite a few posts now and nothing looks conclusive, I do not have an OPC warranty and am worried about being taken to the cleaners. If anyone has some advise on the correct steps to take it would be most welcome.

 

There are some threads on here somewhere about people getting a software update to cure the cold start idle issue.......I had an update on mine for this, and it did cure the cold idle...but short lived. Rough cold idle came back after a few weeks

 

From my experience, use a bottle of fuel injector cleaner did the magic.
I don't know why but after a use, my car doesn't have a cold start idle problem for 2 months or so then coming back.
Then I use again then problem goes away for another couple months.
It's been like that for 1+ years. So I'm guessing we get really bad gas even though I always use top tier gas only.

Go ahead and try it.
I always purchase libro moly sauber and jectron from bavauto.com

 

search

*25 second tranny reset

*software update (rough down shift from 2nd gear-1)

*Cleaning MAF Sensor

i never had rough idle but i tried all the above and car feels like a champ!

 

Thanks for the replies, I will try all the free/cheap alternatives before I take it down the dealers. The rough idle seems to be an intermittent problem for me, but I did the tranny reset with no perceptible difference.

 

the tapping is from the cylinder head. my tapping got worse and very load so i took it to the dealer and they did a head job, it hasn't made any tapping since, but it hasen't been real cold were i live, but the tapping for sure is the hydrolic lifters.