Engine behaving weird...
10-13-2008, 01:18 AM
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My engine today seems to be acting lazy when I started the car this afternoon. The car was running fine in the morning but as it get colder this afternoon my engine's RPM seems to be running low when parked or at stops. Normally my car's engine stays at a steady 700 RPM after the engine warms up. However, this afternoon and tonight it was staying at 400-500 RPM which felt rather awkward. When I drive, my steering wheel vibrates slightly during stops and low speeds. When I take a slow turn at intersections it felt as if the engine would suddenly turn off or die. Could this be because of the temperature that's affecting the engine's behavior? I noticed that lately its getting a bit colder and colder each day since winter is coming and tonight was by far the coldest. 
10-20-2008, 10:57 AM
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Originally Posted by aznunknownx' post='691591' date='Oct 13 2008, 05:18 AM
My engine today seems to be acting lazy when I started the car this afternoon. The car was running fine in the morning but as it get colder this afternoon my engine's RPM seems to be running low when parked or at stops. Normally my car's engine stays at a steady 700 RPM after the engine warms up. However, this afternoon and tonight it was staying at 400-500 RPM which felt rather awkward. When I drive, my steering wheel vibrates slightly during stops and low speeds. When I take a slow turn at intersections it felt as if the engine would suddenly turn off or die. Could this be because of the temperature that's affecting the engine's behavior? I noticed that lately its getting a bit colder and colder each day since winter is coming and tonight was by far the coldest.
10-20-2008, 11:55 AM
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Probably software, as allways 
If you had a couple of years old 545/550 I would say malfunctioning crankhouse pressure regulating valve(s)
Try unscrew your oil filler cap when engine is ideling. what happens is that the crankhouse pressure drop, and so does the idle rpm.
If the valves are not sealed pressure leaks out and rpm drop in the same manner.
Look at this page for part info #13
http://www.realoem.com/bmw/showparts.do?mo...hg=11&fg=15
For reference, people have had your symptoms, and the fix was replacing the valves.
If you had a couple of years old 545/550 I would say malfunctioning crankhouse pressure regulating valve(s)
Try unscrew your oil filler cap when engine is ideling. what happens is that the crankhouse pressure drop, and so does the idle rpm.
If the valves are not sealed pressure leaks out and rpm drop in the same manner.
Look at this page for part info #13
http://www.realoem.com/bmw/showparts.do?mo...hg=11&fg=15
For reference, people have had your symptoms, and the fix was replacing the valves.
10-20-2008, 06:11 PM
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Originally Posted by NPe' post='698109' date='Oct 20 2008, 03:55 PM
Probably software, as allways
For reference, people have had your symptoms, and the fix was replacing the valves.
For reference, people have had your symptoms, and the fix was replacing the valves.
10-21-2008, 02:24 AM
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Z3 Coupe V8Turbo design work ongoing, full race.
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Originally Posted by SergeyM' post='698507' date='Oct 21 2008, 04:11 AM
Oh, no! Not a valve job again. My 545 engine never recovered after the valve job and died with only 15K miles on it. If 4.8 V8 goes too, it will be the last BMW I will ever own.
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