Hard start and rought idle/power loss

[t_marat]

I have never cleaned my MAF, it is self cleaning.

When the air-mass sensor is working normal, the hot wire does not glow. To burn off any deposits and dirt, the control system will heat the wire red hot to 1000 degrees Celsius (1800 F) for about 1 second, after you shut off your engine. This is the cleaning process and only performed if the engine is revved up to at least 2000 rpm. So starting your engine, let it idle for a certain time and shut off means no hot wire cleaning.

That is the 750 MAF, not sure if you have the same system
http://bmwe32.masscom.net/sean750/MA...leshooting.htm

Here's a link you might find interesting,all though it's a Porsche 944 AFM, he's desribing it is a MOTRONIC set up from around the same era as your E34, so they should be very similar our BM's.


http://frwilk.com/944dme/afm.htm

I have read in Bentley that it is supposed to clear itself. its just I remember reading about some MAF cleaner on this board. MAF on my engine is principally the same as in that link, but it has only 4 pins.

I noticed that whenever car starts running rough the exhaust gets more black and clears out as soon as engine starts running normally. smoke isn't very black, but has a tint of blackness. one cylinder not running for some reason?

Other thing. after some hard accelerations engine started making a ticking/knocking sound. sound was coming from the valve cover/intake manifold area. got scared with a thought of piston hitting the valve, but the sound was not metallic, more like something plastic hitting plastic. plus car run normal, with no loss of power. it wasn't fan, tried spinning it with engine off, no obstruction. sound was rather loud, could hear even with hood closed. after a while ticking disappeared. could this be injectors? maybe from time to time one of the injectors starting to leak badly, fouling the spark plug?