Volvo AWD 850 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 2/2002 850 INDEX

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

Transformer type hum when key at position II & engine not running 850 1994

posted by  someone claiming to be Malcolm Davidson on  Fri Nov 10 11:58 CST 2000 [RELATED]

Hi

Does anyone know what a loud transformer ( domestic power reduction unit) type noise coming from the throttle unit in front of the motor, could be. The key is in position II and engine is not running. I have not noticed it before.

Thanks

Malcolm (NZ)







  •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

    Re: Transformer type hum when key at position II & engine not running 850 1994

    posted by  someone claiming to be abe crombie on  Fri Nov 10 16:00 CST 2000 [RELATED]

    Rich K is on to it.

    The fuel pump runs for 1-2 seconds on initial key on and is in the fuel tank so it wouldn't be heard at the front of motor unless it was fuel flow noise which wouldn't be a hum.

    The IAC valve is cycled at a fixed frequency any time the key is in pos II (and when engine is running, but you can't hear it then) on the cars up to the introduction of electronic throttle.







  •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

    Re: Transformer type hum when key at position II & engine not running 850 1994

    posted by  someone claiming to be Rich K. Fairfax, VA on  Fri Nov 10 14:00 CST 2000 [RELATED]

    The Idle Air Motor does exactly what you have described.







    •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

      Re: Transformer type hum when key at position II & engine not running 850 1994

      posted by  someone claiming to be Yuri on  Fri Nov 10 18:56 CST 2000 [RELATED]

      <

      --

      Rich K.>>

      Rich,

      What is the Idle Air Motor? Please enlighten.

      Yuri







      •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

        Re: Transformer type hum when key at position II & engine not running 850 1994

        posted by  someone claiming to be Rich K. Fairfax, VA on  Sat Nov 11 04:49 CST 2000 [RELATED]

        Although it is called the idle air motor, it is a fancy valve(controlled by the Engine Computer) that is regulating the air that is going into the intake manifold. Constant fine tuning, thus the "Humming" noise.







  •   REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

    Re: Transformer type hum when key at position II & engine not running 850 1994

    posted by  someone claiming to be Charles Linden on  Fri Nov 10 12:15 CST 2000 [RELATED]

    Sounds like your talking about the fuel pump. Thats about all I can think of.






<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.