Request for some clarifications
 

Hello Guyz,
(Car: 2001 BMW 325i)
I need guidance on the following:
- When i start my car engine and specially when its still cold if i put the Transmission on "D" or "R" the RPM start to play and go slightly up and down around 500.

- Same if i leave the car idle for a while i get the same result

- Is it normal that when i go more than 5000 RPM i hear a whistle sound before shifting to the next gear?

- Also when i first start the car and its still cold i hear a knocking sound in the Air Pump for a minute then the sound is gone. Check following Video to hear the sound (http://www.youtube.com/watch?v=DdmEiOWV5Zo)

Thanks for your help. :)

On the idle, check all plastic and rubber air tubes from the mass airflow sensor to the throttle(s). Remember that things tend to crack on the bottom side first.

Does your model have the drive-by-wire throttle and multiple throttle valves, or does it have a single throttle and an idle air control valve? If you have a single throttle, you may need to open it up and clean the throttle valve and the idle air control valve. If you have drive by wire, that is beyond my expertise.

On the air pump. Bad news. Your check valve on the exhaust manifold has failed. That is why you hear exhaust pulses through the fan inlet. From the metalic churning sound I hear, you did not catch it soon enough and it has spun your fan backwards until it killed your fan as well. There is a place on eBay that rebuilds fans for $125 (half the cost of a new one), but the valve is not repairable.

To be sure that the valve has failed, pull the hose off the fan and blow through it. A good valve is normally closed. If you can blow into the exhaust manifold, the valve has failed.

Hey Thanks for your reply,
for the Idle problem, i have it checked by an expert and he told me that The Oil Breather is causing these problems, what do you think?
i Think i have a Single throttle and an ICV i will double check that.
Bad news for the Air Pump you are telling me, does it have side effects on the car if i leave for a while or its an urgent problem that i need to fix soon?

Thanks Again,

Hello Again,
Just i wanted to inform that just today i repaired the Rough Idle problem in my car and it turned out that the problem was caused by the Oil Breather , its rubber tubes and a plastic air tubes connected to the Air Mass Sensor.
Now the car is running Smooth.

Thanks,