Drivetrain malfunction club

NONREV said:

I swear by Techron in my Galant and 740LI. I also have a long hour commute and on days I drive the 740 there are some long stretches that I open it up 110+ I'm pretty sure that blows out the carbon as I have had no engine or rough idle issues.

I also think BMW hit a home run with that 6 cylinder they put in the 740 and other models, as I rarely hear any issues engine related. Not sure that extra one second 0-60 is worth all the issues.

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My 740 had plenty of umph. More than enough I always thought. Still would have liked to test a LCI 750 though But overall, the 750's seem to have alot more problems and when do you REALLY get to use that extra HP?? From green light to green light? The inline 6 is BMW's bread and butter. Even the 550's are having the same issues. They need to seriously redo the twin turbo V8 to figure out how to get rid of the carbon build up. Not sure why "most" of the 740's dont have this issue since the design flaw seems to be the direct injection, which is what the 740's have as well, hence they should be having the same issues as consistently, but they dont.
The only issue I EVER had that drove me nuts from day one, is when turning, the engine rpms would go down so I had to accelerate out of a turn, where as any other car would just coast into a turn.

wjhughes420384 said:

I think I know the source of all my faults! mon when I went to start the car(it was very cold) the battery warned me of a low charge. 5 yr old battery, when I had the drivetrain fault (alone with 34 other faults) it was very cold. my guess is that when the battery was going it could not maintain sufficient voltage for all the computers, low voltage could easily cause a computer to fault.
battery replacement was $600!! yikes

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I was going to mention the battery to you! If your car is running smooth except on 'colder' days, check the voltage. BMW computers are very sensitive to battery and misfires and random faults are a few of the symptoms especially when the battery gets to 4+ years. Online, the battery can be had for $350 OE.

When you talk about drivetrain in this thread, is it the transmission or the engine or both? I have noticed that when I drive around 40-50 mph slightly uphill or on a wide turn which causes the tranny to tug around 1100-1200 rpm, I heard a very noticeable noise like a flute sound. The "hwoooo" sound immediately silence when the tranny is at 1500 rpm or higher (downshifts).

Also, after some fast driving (90+ mph), the car has a burned smell and added heat (in garage). The mileage is around 14K and the smell is typically associated with brand new cars, but I still smell it with this one. :dunno:

Injectors again and

I brought my car in for a general service, air filter and oil change. I am almost at 40k. I also told them that even though I haven't seen any codes pop up since they replaced the injectors a few months ago I am still getting a rough idle when waiting at lights.

They called me back to tell me that it needs all new injectors again. They found a bunch of codes stored from the past few months. It turns out it was only 4 inj that were replaced.

I picked up the car and now I am hearing a loud engine tap. I didn't have this before so why do I have it now. It is like a chatter or a tap. Sounds like lifters though. I am also getting a metallic sounding vibration and a strange odor after driving. Almost smells like a high mileage jap car. It is back for service. I had good luck other than these inj.

Thanks,

B

Joined in November after being to dealer 3 times for "intermittent vibrations & shuddering upon deceleration, acceleration and idle". Rough ride symptoms past 40 mph. Low oil light occurs every 800 miles or so, now it's more frequent. They changed out spark plugs, injectors, did vapor tests to no avail. Repair attempts correct it for a day or so then symptoms are back.My dream car is no longer that, it's becoming nightmare instead. Also, rough idle at times, what seems like misfires, and BMW of NA sending field tech on Monday for last repair attempt. Dealer could not replicate symptoms first time around 16,000 miles but soon afterwards shop foreman test drove with me and he got it! His opinion was the eco-pro program that shuts off the vehicle at red lights...which I keep OFF. Anyway, I have a list from the forum of items other 750 owners have had replaced or repaired for similar symptoms and I will give it to visiting field tech & dealer on Monday for their records. My 3rd BMW and the only "bad" one so far. I am covered under Florida Lemon Law but really want to have my 750 fixed....if not I was going to look at the M6 since my hubby suggested that because no new 750 until 2016 and new M6 just came out.....a bit afraid to go back to BMW if my 750 cannot run well!!! Any advice or ideas for my last repair attempt?