rocitreal

Hello All,
Have some strange issues I thought some of you might have some sort of ideas about... Any input would be greatly appreciated.
I purchased a 2006 550i about 2 months ago that may never been in really cold weather before being relocated to Missouri.. It ran great when I got it but the next day I noticed the Heater did not work. Took it to the most reputable dealer service shop in town and they said the water pump impeller had put metal shavings into the coolant ruining the auxiliary water pump. They changed the water pumps, flushed the coolant lines and refilled.

Then a week or so later the first time it was really cold (10-20 Degrees) when I started the car it barely starts. After it starts I let it run for 30 about 30 seconds and rev it slightly to 2k. Then the RPM gauge starts jumping from 1-2k? I turn it off and back on. It is shaking misfiring horribly and service light comes on. After turning it off and on 3-4 times it finally starts ok. I let it warm up for 5 minutes and then it drives fine. The car continues to drive fine and the service light goes off until about a week later when the temperatures are very cold again it does the same thing.

I go to get some Techron and put in a bottle to see if it might help. It does not seem to help the cold weather start symptoms at all however I get more issues. The MPG gauge starts jumping up to 12 when at a stop. The Mileage drops from 17MPG average down to 11MPG on the display? There is a smell of oil burning possibly, but no smoke out of the tail pipe.

I I take it back to the same shop and they think its just the spark plugs were not the BMW issued and need changed. The codes they pulled were 4 random misfiring cylinders (but only when cold start). After they change the plugs I go drive the car and the MPG Gauge is still jumping around and the gas mileage is still extremly bad. I test drove the car 12 miles and lost about 1/8 of a tank of gas. The MPG display will not go above 12.2MPG. I tell the service manager that the car is not fixed. So they look at it for vacuum leaks and CVV and such but find nothing. They relearn the computer but still same thing with the gas milage and the gauge jumping. They now are telling me to come pick it up (so they do not have to mess with it anymore) and want $550 for the spark plug change.

Any ideas at all? Thanks!
-Gary

sequaz

Wow that's weird. My boy had the same problem in his 05 530i but the problem began after changing the spark plugs.

ncsugrad2006

On the older N62 engines there was an issue with the intermediate levers wearing which would cause a cold start idle issue (would get random misfires, the car would then shut down the cylinder(s) with the misfires which made it feel even rougher).

I thought this was resolved a year or two before your car was even made, but I thought I'd at least throw it out there to consider as the symptoms are nearly identical. I had it happen on my 2004 and it only happened on cold mornings on the first start of the day. I finally figured out that if I got out of the driveway pretty quick while it was running rough and got going it wouldn't throw codes, but if I didn't, I'd have to restart the engine to get everything to reset. Ultimately this condition does not hurt anything, just a bit of a pain/embarrassing

Symptoms were exactly the same though on mine with this issue--rough idle, RPM's jumping between 1-2K, misfire codes if it went on long enough and everything being just fine after a restart..

Here is some info on that SIB:
http://www.xoutpost.com/attachments/...-20idle-1-.pdf

EddieboyS

I have an 06 550i and noticed that it hesitated and did not run well until completely warmed up on cold mornings. It did cough and sputter a couple of times as well but not often. Recently my active steering unit went bad and when it was replaced under extended warranty the BMW dealer had to completely reprogram the ECU. I've not had the hesitation problem since that time.

As an aside, I recently had a bad batch of gas that resulted in similar symptoms to yours, revving idle, sputtering, hesitation, poor gas mileage. Put in 2 cans of BG44k and filled the tank with premium. It's been running smooth as silk since then.

ncsugrad2006

I have also read there was a valvetronics ECU software update as well that helps..