Exhaust cloud on start up

MMVI · 07-11-2006, 03:44 PM

I posted a topic recently which posed the question, does anyone else get the occasional cloud of smoke from the exhaust on start-up regardless of conditions or how the car was treated during its last operation.

It did not get much interest, and I did not get an answer but I have now found out for myself what is going on and it is interesting so I thought I would share it again.

A BMW ES engineer told me that the car will occasionally dump an amount of fuel down the system on start-up to purge and clean the system as a self maintenance exercise determined by the ECU.

Its was a little disconcerting but now I know its normal and nothing to worry about.

E90Fleet · 07-11-2006, 03:53 PM

On cold/cool days its also commin on 3 Series ( E90 and before) to see what some people think is white smoke, but is actually steam for a couple minutes after the car is started

MMVI · 07-11-2006, 03:57 PM

Indeed.. I have seen the steam and asked this in a topic a long time ago to which you replied fleet. If sat in a jam for example on a cold day you can see other BMWs blowing this steam where most other engines do not.

It must be something in their architecture that causes this, however once again nothing to worry about.

Still havent got my 3100 hesitation sorted by the way.
BMW say there is nothing wrong, buggers.

07-11-2006, 03:44 PM	#1
MMVI Lieutenant 79 Rep 449 Posts Drives: 4 something Join Date: Aug 2005 Location: UK iTrader: (0)	Exhaust cloud on start up - answer I posted a topic recently which posed the question, does anyone else get the occasional cloud of smoke from the exhaust on start-up regardless of conditions or how the car was treated during its last operation. It did not get much interest, and I did not get an answer but I have now found out for myself what is going on and it is interesting so I thought I would share it again. A BMW ES engineer told me that the car will occasionally dump an amount of fuel down the system on start-up to purge and clean the system as a self maintenance exercise determined by the ECU. Its was a little disconcerting but now I know its normal and nothing to worry about.
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07-11-2006, 03:53 PM	#2
E90Fleet Lieutenant General 1312 Rep 10,185 Posts Drives: BMW Join Date: Apr 2005 Location: South Africa iTrader: (0)	On cold/cool days its also commin on 3 Series ( E90 and before) to see what some people think is white smoke, but is actually steam for a couple minutes after the car is started __________________ BMW if you are reading, I need a job, Please.
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07-11-2006, 03:57 PM	#3
MMVI Lieutenant 79 Rep 449 Posts Drives: 4 something Join Date: Aug 2005 Location: UK iTrader: (0)	Indeed.. I have seen the steam and asked this in a topic a long time ago to which you replied fleet. If sat in a jam for example on a cold day you can see other BMWs blowing this steam where most other engines do not. It must be something in their architecture that causes this, however once again nothing to worry about. Still havent got my 3100 hesitation sorted by the way. BMW say there is nothing wrong, buggers.
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