I have a Honda Civic 2009 LX Sedan and lately it has been making some whiny noise and gets louder the more I accelerate. I had the power steering pump replaced and also the alternator as well as a idler pulley. I been doing some research online and I found out that there are two different things. When I tried looking up the part for my car, it shows the same pulley for the idler and the tensioner. Does this mean that its two parts in one or the belt tensioner pulley and idle pulley are the same part just different locations? I have a picture for better explanation, the circled things are the ones I need clarification on.

 

tensior pully moves. holds tension.
idler pully sits still. i.e. its just there to route the belt back around.
idler and tensioner are 2 dif pulleys with 2 dif functions.
and when buying aftermarket pulley and belt stuff. stick with oem or Gates. (my advice)

 

I went under the car and I looked at it closely turns out that the black pulley is connected to power steering pump. I am so confused with this car and that whining noise driving me insane every time I drive

 

whining could be altenator......