2008 Kia Optima: Low-pitched "hair dryer" sound on AM band

I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
the AM band in ACC mode and when the engine is running. FM reception
is OUTSTANDING and I can lock on to stations up to 80 miles away!

AM? Not nearly as good. Would a capacitor/s help and where should I
place one/them?

Any suggs??

-CC

ChrisCoaster wrote:
> I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
> the AM band in ACC mode and when the engine is running. FM reception
> is OUTSTANDING and I can lock on to stations up to 80 miles away!
>
> AM? Not nearly as good. Would a capacitor/s help and where should I
> place one/them?
>
> Any suggs??
>
> -CC

if it's in ACC then it has to be something non-engine related. Heater
blower fan, perhaps?

nate

--
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ChrisCoaster > wrote:
>I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
>the AM band in ACC mode and when the engine is running. FM reception
>is OUTSTANDING and I can lock on to stations up to 80 miles away!

Start pulling fuses until you find the circuit the noise source is on.

>AM? Not nearly as good. Would a capacitor/s help and where should I
>place one/them?

Maybe, or possibly a choke. If you hear the noise with the engine off and
the ignition in accessory mode, you know that it has nothing to do with the
engine or engine controls, but with one of the accessory devices. Find the
noise source and either fix it or install some filtering at the source.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

ChrisCoaster wrote:
> I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
> the AM band in ACC mode and when the engine is running. FM reception
> is OUTSTANDING and I can lock on to stations up to 80 miles away!
>
> AM? Not nearly as good. Would a capacitor/s help and where should I
> place one/them?
>
> Any suggs??
>
> -CC

Electrical noise from the car can get into the radio in two ways,
radiated noise and noise riding on the power lead.

Noise that is radiated by the car and picked up by the antenna is much
harder to get rid of. It is almost impossible to filter it out of the
antenna system. The normal method is to eliminate it as close to the
source as possible. Are you using noise-suppression spark plugs? You
should be. Even so, a bad plug can create bad ignition noise, though it
sounds more like static than a hair dryer. A bad alternator can make
lots of electrical noise. Make sure you have a good alternator and that
filter on it is good.

Noise from the electric wiring that gets into the radio from the power
lead is easier to stop. Most radios have a good filter in their power
supply section. A component of that filter may be bad. Or, if it is a
cheap radio, the filter may just not be good enough. Radio Shack used
to sell a power lead filter that you put in the lead bringing power to
the radio.

Diagnostics. Hold a portable AM radio next to your car when the car is
running. Note the noise. Do the same with a few other cars. Is the
noise worse near YOUR car? If so, you are radiating noise and need to
fix that. If that portable does not note excess noise near your car,
than the noise is likely getting into your car radio on the power lead.

ChrisCoaster wrote:
> I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
> the AM band in ACC mode and when the engine is running. FM reception
> is OUTSTANDING and I can lock on to stations up to 80 miles away!
>
> AM? Not nearly as good. Would a capacitor/s help and where should I
> place one/them?
>
> Any suggs??
>
> -CC


If the sound is there on AM but not FM, then unfortunately that means
its not coming in through the radio amplifier electronics, but is being
picked up by the antenna itself. AM modulation is susceptible to this
and the car's ignition or charging system is obviously not well shielded
You can try a series inductor on the radio power feed with a parallel
capacitor to ground after the inductor (an LC filter circuit) but I give
it minimal odds of success.

Scott Dorsey wrote:
> ChrisCoaster > wrote:
>> I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
>> the AM band in ACC mode and when the engine is running. FM reception
>> is OUTSTANDING and I can lock on to stations up to 80 miles away!
>
> Start pulling fuses until you find the circuit the noise source is on.
>
>> AM? Not nearly as good. Would a capacitor/s help and where should I
>> place one/them?
>
> Maybe, or possibly a choke. If you hear the noise with the engine off and
> the ignition in accessory mode, you know that it has nothing to do with the
> engine or engine controls, but with one of the accessory devices.


I wouldn't go that far- if the engine or transmission or body controller
module is powered (and the body controller often is powered in ACC since
it controls things like the radio, power windows, etc.) then it could
still be harmonics of the processor or bus clock or logic circuits. Just
like a badly shielded home PC.

On Apr 30, 10:18*am, (Scott Dorsey) wrote:
> ChrisCoaster > wrote:
> >I have a 2008 Kia Optima sedan with a terrible "hairdryer" sound on
> >the AM band in ACC mode and when the engine is running. *FM reception
> >is OUTSTANDING and I can lock on to stations up to 80 miles away!
>
> Start pulling fuses until you find the circuit the noise source is on.
>
> >AM? Not nearly as good. *Would a capacitor/s help and where should I
> >place one/them?
>
> Maybe, or possibly a choke. *If you hear the noise with the engine off and
> the ignition in accessory mode, you know that it has nothing to do with the
> engine or engine controls, but with one of the accessory devices. *Find the
> noise source and either fix it or install some filtering at the source.
> --scott
> --
> "C'est un Nagra. *C'est suisse, et tres, tres precis."
_____________________
I do apologize - I neglected one piece of info: I had the service
dept manager listen to AM on several 2008 optimas identical to mine
with the same exact stereo, and they all had the same sound - at the
same points on the AM band. FM reception flawless on all of them.

Will some sort of capacitor/noise suppresion still help in my case?

thanks,

-CC

ChrisCoaster > wrote:
>I do apologize - I neglected one piece of info: I had the service
>dept manager listen to AM on several 2008 optimas identical to mine
>with the same exact stereo, and they all had the same sound - at the
>same points on the AM band. FM reception flawless on all of them.

Not surprising.

>Will some sort of capacitor/noise suppresion still help in my case?

Depends on what is causing the problem. Start pulling fuses.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Apr 30, 7:01*pm, (Scott Dorsey) wrote:
> > wrote:
> >I do apologize - I neglected one piece of info: *I had the service
> >dept manager listen to AM on several 2008 optimas identical to mine
> >with the same exact stereo, and they all had the same sound - at the
> >same points on the AM band. *FM reception flawless on all of them.
>
> Not surprising.
>
> >Will some sort of capacitor/noise suppresion still help in my case?
>
> Depends on what is causing the problem. *Start pulling fuses.
> --scott
> --
> "C'est un Nagra. *C'est suisse, et tres, tres precis."
_________________
So, with the car in ACC, I pulled the following fuses, one at a time:

- Clock
- Airbag sens
- DRL
- Several "spares"
- Taillights
- Fuel pump
- ABS
- Power seat
- sunroof

etc.

Notice a pattern here? Most of those fuses govern items that run full-
time, including sensors.
Nothing eleminated the low-speed hair dryer noise in the background of
certain AM stations.

I didn't bother pulling fuses for things like trunk lights or interior
lighting, as they are on-demand items, meaning they usually come on
only when you are entering or exiting the cabin or operating the
decklid.

All nuts that transfer current between the battery, the alternator,
and the fuse boxes, as well as any ground terminals(that I could
access!) to firewall or engine block have been checked tight and
retightened by me.

? ? ?

-CC

ChrisCoaster wrote:
> On Apr 30, 7:01 pm, (Scott Dorsey) wrote:
>> ChrisCoaster > wrote:
>>> I do apologize - I neglected one piece of info: I had the service
>>> dept manager listen to AM on several 2008 optimas identical to mine
>>> with the same exact stereo, and they all had the same sound - at the
>>> same points on the AM band. FM reception flawless on all of them.
>> Not surprising.
>>
>>> Will some sort of capacitor/noise suppresion still help in my case?
>> Depends on what is causing the problem. Start pulling fuses.
>> --scott
>> --
>> "C'est un Nagra. C'est suisse, et tres, tres precis."
> _________________
> So, with the car in ACC, I pulled the following fuses, one at a time:
>
> - Clock
> - Airbag sens
> - DRL
> - Several "spares"
> - Taillights
> - Fuel pump
> - ABS
> - Power seat
> - sunroof
>
> etc.
>
> Notice a pattern here? Most of those fuses govern items that run full-
> time, including sensors.
> Nothing eleminated the low-speed hair dryer noise in the background of
> certain AM stations.
>
> I didn't bother pulling fuses for things like trunk lights or interior
> lighting, as they are on-demand items, meaning they usually come on
> only when you are entering or exiting the cabin or operating the
> decklid.
>
> All nuts that transfer current between the battery, the alternator,
> and the fuse boxes, as well as any ground terminals(that I could
> access!) to firewall or engine block have been checked tight and
> retightened by me.
>
> ? ? ?
>
> -CC

Did you find the fuse for the heater blower fan? that's still my best
guess.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel