Buzzing sound

Hey guys...

1993 5.0 Cobra... basically stock. When I turn off the engine, there's a high-pitched whine that lasts for 1 or 2 seconds, then dies. Car has an aftermarket stereo, but I don't know why that would matter, except that there is still electricity in the "system"... you know, when you unplug a radio and it runs for a second after still...

Anyone else have this problem? It's pretty weird.

Thank you.

Brad

First things that come to mind....

Possibly the AC "equalizing" after the motor is shut off... remember the AC
compressor is going to run in any heater position that blows air on glass...

Possibly a vacuum leak.... there will be a vacuum storage cannister of some
sort under the hood... The motor might keep up with a smallish vacuum leak
but it can still make enough sound (usually either a "hiss" or perhaps a
"reedy" sound depending on the nature of any leak) to be heard as it
normalizes across the system...


>"Brad and Karen" > wrote in message
>news:Ztlak.42843$kx.151@pd7urf3no...
>Hey guys...
>
>1993 5.0 Cobra... basically stock. When I turn off the engine, there's a
>high-pitched whine that lasts for 1 or 2 seconds, then dies. Car has an
>aftermarket stereo, >but I don't know why that would matter, except that
>there is still electricity in the "system"... you know, when you unplug a
>radio and it runs for a second after >still...
>
>Anyone else have this problem? It's pretty weird.
>
>Thank you.
>
>Brad



First things that come to mind....

Possibly the AC "equalizing" after the motor is shut off... remember the AC
compressor is going to run in any heater position that blows air on glass...

Possibly a vacuum leak.... there will be a vacuum storage cannister of some
sort under the hood... The motor might keep up with a smallish vacuum leak
but it can still make enough sound (usually either a "hiss" or perhaps a
"reedy" sound depending on the nature of any leak) to be heard as it
normalizes across the system...

On Jul 1, 2:59 am, "Brad and Karen" > wrote:
> Hey guys...
>
> 1993 5.0 Cobra... basically stock. When I turn off the engine, there's a high-pitched whine that lasts for 1 or 2 seconds, then dies. Car has an aftermarket stereo, but I don't know why that would matter, except that there is still electricity in the "system"...

Any chance that you got one of those big-arse aftermarket stereo
capacitors in there that is holding a charge for 1 or 2 seconds?

Kruse wrote:
> On Jul 1, 2:59 am, "Brad and Karen" > wrote:
>> Hey guys...
>>
>> 1993 5.0 Cobra... basically stock. When I turn off the engine,
>> there's a high-pitched whine that lasts for 1 or 2 seconds, then
>> dies. Car has an aftermarket stereo, but I don't know why that
>> would matter, except that there is still electricity in the
>> "system"...
>
> Any chance that you got one of those big-arse aftermarket stereo
> capacitors in there that is holding a charge for 1 or 2 seconds?

Is the heater/air fan always on when the ignition is? Is there a leaf
in the squirrel cage?

--
Frank ess

Hey guys, thank you for the input.

I never looked at the heater fan position. That is an easy thing to check.
Thanks. Yeah, the stereo is more than stock - I dunno what it is cause the
last guy put it in.

But I think Jim might have it... it does kina go "reedy".... almost like
it's exhaling.

The car needs to go back to Ford for some minor safety work, so I'll have
them look at it.

Thank you all.

Brad


"Frank ess" > wrote in message
...
>
>
> Kruse wrote:
>> On Jul 1, 2:59 am, "Brad and Karen" > wrote:
>>> Hey guys...
>>>
>>> 1993 5.0 Cobra... basically stock. When I turn off the engine,
>>> there's a high-pitched whine that lasts for 1 or 2 seconds, then
>>> dies. Car has an aftermarket stereo, but I don't know why that
>>> would matter, except that there is still electricity in the
>>> "system"...
>>
>> Any chance that you got one of those big-arse aftermarket stereo
>> capacitors in there that is holding a charge for 1 or 2 seconds?
>
> Is the heater/air fan always on when the ignition is? Is there a leaf in
> the squirrel cage?
>
> --
> Frank ess