exhaust smoke - BMW Forum

kaspakick · 11-01-2009, 07:03 AM

Hi everyone.
Im new to this site. Got my BMW 520d two months ago. 02. 77K. Had the flaps done straight away to avoid problems, and know that they do have turbo problems but that seemed ok.
However, now noticing some smoke coming from exhaust when accelerate hard. Doesnt appear to be burning any oil though. Dip stick still shows full. Any idea what this could be?

witeshark · 11-01-2009, 07:48 AM

Most turbo diesels tend to smoke a bit around wide open throttle. But you may wanna research in more detail on your specific car.

marti5 · 11-01-2009, 09:34 AM

You may have an injector on the way out....

camano4 · 11-01-2009, 01:48 PM

What color is the smoke? If it's black ~ it's fuel / air mixture. Air filter?
White? Over fuel (or other problems which would be more apparent)
Blue? Oil burning (except I have experienced this in mechanical diesels, specifically V series engines with an imbalance between left and right cylinder banks).
If it's only upon a rapid acceleration, I wouldn't be too awfully concerned, unless of course your economy has gone down a lot and if there are any SES indications on the dash.

FCPGroton · 11-04-2009, 08:16 AM

Like witeshark said, if it is only smoking a little bit under WOT, I would not worry much about it. Even the clean Diesels tend to do this some.

victorpagn · 11-11-2009, 09:22 AM

i drive a 02 325i and i only get exahust smoke sometimes with cold starts and rough idle and sometimes running the car at low rpm the car start to get rough idle and start to smoke but once i give some gas it clears up. im really worry it been doing this for couple months already. can some one help?

FCPGroton · 11-11-2009, 09:34 AM

Do you have any warning lights or messages? Does it do this when it is warm out or after the engine has warmed up?

victorpagn · 11-11-2009, 09:42 AM

it dont have no light on so ever and it does it dont matter the weather like this morning i start it up and it started with rough idle and it start to smoke bad like gray color so i shut it off havent turn it on again. lats night i was at a red light and i felt the car shake a lil and when it turn green that i step on the gas the car started to low the rpms like it was to shut off with rough idle and smell like rotten eggs but once it shited to 2nd gear it cleared and drove normal.

FCPGroton · 11-11-2009, 10:22 AM

OK, sounds like the car is running rich. When was the last time you had a tune up done?

victorpagn · 11-11-2009, 03:09 PM

an oil change you mean? cuz i did an oil change 4,000 miles ago

victorpagn · 11-11-2009, 03:15 PM

an oil change you mean? i did an oil change 4,000 miles ago with 15w40 non syntetic. afyer i turned on this morning and started to smoke bad i let it sit and i turned back on like an hour after, i let it idle and like 2 minutes after the smoke stops im wondering if is the valve seals

camano4 · 11-12-2009, 03:00 PM

Victor ~ grey / whit smoke on a diesel could be low compression or over fueling (wet stacking) I would have to imagine there is a temperature sensor that might be failing and possibly is allowing the ECU to over-fuel the engine... but I'm just not that familiar with BMW's fuel management for diesels. The thing that has me leaning that way is how it cleared up after you let it sit. That would have allowed a sensor to 'heat up' in the coolant and change the voltage signal to the ECU. Keep us posted ~ this is an interesting one...
Good luck!

Greg

victorpagn · 11-15-2009, 05:47 PM

camano4, well is weird the car been without smoke for 5 days in roll i dont know what really is im guessing is the crankcase valve but not sure, i know i got to have a lick some where cuz sometimes smell like oil burning...

victorpagn · 11-15-2009, 05:50 PM

oh and is not diesel is a 2002 325i 2.5lt engine automatic with 104,000 miles and i also change the fuel pressure regulature and is together with the fuel filter.

camano4 · 11-15-2009, 07:18 PM

Hi Victor,

Sorry ~ this thread started with a diesel, and I overlooked that yours was gasoline powered.
In the past, I have run across cold start valve problems and temperature sensor problems (which I would kind of lean towards) but I am not versed in the BMW fuel management system. I would have to imagine the ECU enriches the fuel mixture when the engine is cold, therefore I would look at a coolant temperature sensor being out of range, or 'lazy' if you will. You said you replaced the fuel pressure regulator with the filter? I did not realize they were a combined unit... from what I have seen, they aren't.
Your comment on smelling 'oil burning' ~ is this an 'outside odor', like oil dripping on an exhaust manifold or is it an 'internal' smell of oil being burned out the tail pipe? With catalytic converters, I have seen engines that have burned tremendous amounts of oil in the combustion process, yet the tail pipe was not showing any oily residue... keeps us posted!

Greg