Can someone identify this sound?
 

I've got a 99 Nissan Altima with an odd sound to it while accelerating.
It's a
regular thrumming, sort of "fluttery" sound. My 94 has a very similar sound
as well, but a bit more harsh I think (due to less sound deadening maybe),
so it could very well be normal. I'd really like to know what causes it
though.

I went for a drive and recorded the sound inside the cabin, it's a bit hard
to make out but any time I accelerate it's there. It's most noticeable
under moderate acceleration it seems.

I've got a short clip and the full length at
http://www3.ns.sympatico.ca/pmason/altmp3/.

To me it almost sounds like a resonance that is happening somewhere, in the
exhaust manifold maybe or some part of the engine bay. I had a Civic a few
years ago that due to an accident and repair had the engine mount touching
the frame of the car and unless I wedged something between the two parts, I
would get nasty sounding knocking/vibration while driving. Maybe this is
the same sort of thing. It's almost like some metal part of the engine is
vibrating against the hood, or the frame, or something.

Also, I get a slight tapping for 1 or 2 seconds at startup when the engine
is warm (but has been sitting for maybe 20 minutes). You can make it out
faintly at the start of the longer recording here. I've been told it may be
a stuck lifter, so is there any chance that that could account for the
noise? It seems to happen at about the same frequency or tempo as this
sound, taking the lower idle rpms into account. I would expect something
like that to have a lighter sound to it
than this does, but I'm no expert. I've been telling myself that it's
happening (revolving) too quickly to be something to do with a particular
cylinder or valve, but again, I'm just guessing.

I know it's pretty hard to make any guesses, educated or otherwise just
based on a couple of hard to make out samples, but I would like to hear any
theories just the same.

Thanks!

On Fri, 21 Jan 2005 01:13:55 GMT, "JM" >
wrote:

>I've got a 99 Nissan Altima with an odd sound to it while accelerating.
>It's a
>regular thrumming, sort of "fluttery" sound. My 94 has a very similar sound
>as well, but a bit more harsh I think (due to less sound deadening maybe),
>so it could very well be normal. I'd really like to know what causes it
>though.
>
>I went for a drive and recorded the sound inside the cabin, it's a bit hard
>to make out but any time I accelerate it's there. It's most noticeable
>under moderate acceleration it seems.
>
>I've got a short clip and the full length at
>http://www3.ns.sympatico.ca/pmason/altmp3/.

I listened to the Full Version
Not quite ready for Carnegie Hall
( John Cage is spinning in his grave )

IMO, there is a MOUSE in your engine compartment playing a castanet,
hitting it with a drumstick. I believe I heard the exact same sound
on a Tito Puente album.

Lg


>To me it almost sounds like a resonance that is happening somewhere, in the
>exhaust manifold maybe or some part of the engine bay. I had a Civic a few
>years ago that due to an accident and repair had the engine mount touching
>the frame of the car and unless I wedged something between the two parts, I
>would get nasty sounding knocking/vibration while driving. Maybe this is
>the same sort of thing. It's almost like some metal part of the engine is
>vibrating against the hood, or the frame, or something.
>
>Also, I get a slight tapping for 1 or 2 seconds at startup when the engine
>is warm (but has been sitting for maybe 20 minutes). You can make it out
>faintly at the start of the longer recording here. I've been told it may be
>a stuck lifter, so is there any chance that that could account for the
>noise? It seems to happen at about the same frequency or tempo as this
>sound, taking the lower idle rpms into account. I would expect something
>like that to have a lighter sound to it
>than this does, but I'm no expert. I've been telling myself that it's
>happening (revolving) too quickly to be something to do with a particular
>cylinder or valve, but again, I'm just guessing.
>
>I know it's pretty hard to make any guesses, educated or otherwise just
>based on a couple of hard to make out samples, but I would like to hear any
>theories just the same.
>
>Thanks!
>
>
>
>

On Fri, 21 Jan 2005 01:13:55 GMT, "JM" >
wrote:

>I've got a 99 Nissan Altima with an odd sound to it while accelerating.
>It's a
>regular thrumming, sort of "fluttery" sound. My 94 has a very similar sound
>as well, but a bit more harsh I think (due to less sound deadening maybe),
>so it could very well be normal. I'd really like to know what causes it
>though.
>
>I went for a drive and recorded the sound inside the cabin, it's a bit hard
>to make out but any time I accelerate it's there. It's most noticeable
>under moderate acceleration it seems.
>
>I've got a short clip and the full length at
>http://www3.ns.sympatico.ca/pmason/altmp3/.

I listened to the Full Version
Not quite ready for Carnegie Hall
( John Cage is spinning in his grave )

IMO, there is a MOUSE in your engine compartment playing a castanet,
hitting it with a drumstick. I believe I heard the exact same sound
on a Tito Puente album.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Wait a minute. That was your TURN SIGNAL I was hearing. Not the
abnormal sound you're referring to.

I dunno. Sounds OK to me, other than that, someone fell into a Waring
Bread Dough blending machine, and his keys and pocket change went
through the gears one at a time....
Lg


>To me it almost sounds like a resonance that is happening somewhere, in the
>exhaust manifold maybe or some part of the engine bay. I had a Civic a few
>years ago that due to an accident and repair had the engine mount touching
>the frame of the car and unless I wedged something between the two parts, I
>would get nasty sounding knocking/vibration while driving. Maybe this is
>the same sort of thing. It's almost like some metal part of the engine is
>vibrating against the hood, or the frame, or something.
>
>Also, I get a slight tapping for 1 or 2 seconds at startup when the engine
>is warm (but has been sitting for maybe 20 minutes). You can make it out
>faintly at the start of the longer recording here. I've been told it may be
>a stuck lifter, so is there any chance that that could account for the
>noise? It seems to happen at about the same frequency or tempo as this
>sound, taking the lower idle rpms into account. I would expect something
>like that to have a lighter sound to it
>than this does, but I'm no expert. I've been telling myself that it's
>happening (revolving) too quickly to be something to do with a particular
>cylinder or valve, but again, I'm just guessing.
>
>I know it's pretty hard to make any guesses, educated or otherwise just
>based on a couple of hard to make out samples, but I would like to hear any
>theories just the same.
>
>Thanks!
>
>
>
>

Sounds just like my ex's '93 Altima from what I can hear in the recording -
no powertrain problems through it's 153K-mile lifetime until it got smooshed
by an Infinity SUV. Concerning the other noise, I have known 2.4L Nissan's
to be picky about oil filters. Some non-Nissan oil filters lack an effective
anti-drainback valve which can cause some noise for a few seconds on
startup.

Roger

"JM" > wrote in message
...
> I've got a 99 Nissan Altima with an odd sound to it while accelerating.
> It's a
> regular thrumming, sort of "fluttery" sound. My 94 has a very similar
> sound
> as well, but a bit more harsh I think (due to less sound deadening maybe),
> so it could very well be normal. I'd really like to know what causes it
> though.
>
> I went for a drive and recorded the sound inside the cabin, it's a bit
> hard
> to make out but any time I accelerate it's there. It's most noticeable
> under moderate acceleration it seems.
>
> I've got a short clip and the full length at
> http://www3.ns.sympatico.ca/pmason/altmp3/.
>
> To me it almost sounds like a resonance that is happening somewhere, in
> the
> exhaust manifold maybe or some part of the engine bay. I had a Civic a
> few
> years ago that due to an accident and repair had the engine mount touching
> the frame of the car and unless I wedged something between the two parts,
> I
> would get nasty sounding knocking/vibration while driving. Maybe this is
> the same sort of thing. It's almost like some metal part of the engine is
> vibrating against the hood, or the frame, or something.
>
> Also, I get a slight tapping for 1 or 2 seconds at startup when the engine
> is warm (but has been sitting for maybe 20 minutes). You can make it out
> faintly at the start of the longer recording here. I've been told it may
> be
> a stuck lifter, so is there any chance that that could account for the
> noise? It seems to happen at about the same frequency or tempo as this
> sound, taking the lower idle rpms into account. I would expect something
> like that to have a lighter sound to it
> than this does, but I'm no expert. I've been telling myself that it's
> happening (revolving) too quickly to be something to do with a particular
> cylinder or valve, but again, I'm just guessing.
>
> I know it's pretty hard to make any guesses, educated or otherwise just
> based on a couple of hard to make out samples, but I would like to hear
> any
> theories just the same.
>
> Thanks!
>
>
>
>
>

JM wrote:

> I've got a 99 Nissan Altima with an odd sound to it while accelerating.
> It's a
> regular thrumming, sort of "fluttery" sound. My 94 has a very similar sound
> as well, but a bit more harsh I think (due to less sound deadening maybe),
> so it could very well be normal. I'd really like to know what causes it
> though.
>
> I went for a drive and recorded the sound inside the cabin, it's a bit hard
> to make out but any time I accelerate it's there. It's most noticeable
> under moderate acceleration it seems.
>
> I've got a short clip and the full length at
> http://www3.ns.sympatico.ca/pmason/altmp3/.
>
> To me it almost sounds like a resonance that is happening somewhere, in the
> exhaust manifold maybe or some part of the engine bay. I had a Civic a few
> years ago that due to an accident and repair had the engine mount touching
> the frame of the car and unless I wedged something between the two parts, I
> would get nasty sounding knocking/vibration while driving. Maybe this is
> the same sort of thing. It's almost like some metal part of the engine is
> vibrating against the hood, or the frame, or something.
>
> Also, I get a slight tapping for 1 or 2 seconds at startup when the engine
> is warm (but has been sitting for maybe 20 minutes). You can make it out
> faintly at the start of the longer recording here. I've been told it may be
> a stuck lifter, so is there any chance that that could account for the
> noise? It seems to happen at about the same frequency or tempo as this
> sound, taking the lower idle rpms into account. I would expect something
> like that to have a lighter sound to it
> than this does, but I'm no expert. I've been telling myself that it's
> happening (revolving) too quickly to be something to do with a particular
> cylinder or valve, but again, I'm just guessing.
>
> I know it's pretty hard to make any guesses, educated or otherwise just
> based on a couple of hard to make out samples, but I would like to hear any
> theories just the same.
>
> Thanks!
>
>
>
>
>
Power steering pump...
Just a guess...because the only sound I hear besides your interior
noises, is directly in proportion to engine speed....like a belt driven
accessory..aka: power steering pump

--
Paul
'91 XL1200
'77 GL1000 (W.I.P.)
"I feel more like I do now than when I got here"

"Sportster4Eva" > wrote in message
...
> Power steering pump...
> Just a guess...because the only sound I hear besides your interior
> noises, is directly in proportion to engine speed....like a belt driven
> accessory..aka: power steering pump

Yeah, that's audible too, but it's a constant tone (annoying in itself but
my 94 was the same way and never had any problems with the pump). The sound
I'm wondering about is a rhythmic, repeating sound.

On Sat, 22 Jan 2005 02:17:33 GMT, "JM" >
wrote:
>
> The sound
>I'm wondering about is a rhythmic, repeating sound.
>

There are only about 2,000 of those on your *tape.*

You need to use an active audio filter to single out the one you're
interested in, possibly along with a low frequency spectrum analyzer.

What you have done is thrown a plate full of meatball sauce at us and
challenged the group to find "the spice."

Nobody here can do that. In fact, your best bet might be to send it
off to the CIA.

Lg

"Lawrence Glickman" > wrote in message
> > The sound
> >I'm wondering about is a rhythmic, repeating sound.

> There are only about 2,000 of those on your *tape.*
> You need to use an active audio filter to single out the one you're
> interested in, possibly along with a low frequency spectrum analyzer.
> What you have done is thrown a plate full of meatball sauce at us and
> challenged the group to find "the spice."

I tried a few different filters on the recording but couldn't find the right
frequencies to amplify or drop. Anyway I didn't really expect anyone to be
able to make a 100% diagnosis from it, but I thought I'd try. It was kind
of fun recording and listening to my driving so it wasn't a total waste of
time :)

On Sat, 22 Jan 2005 03:05:33 GMT, "JM" >
wrote:

>
>"Lawrence Glickman" > wrote in message
>> > The sound
>> >I'm wondering about is a rhythmic, repeating sound.
>
>> There are only about 2,000 of those on your *tape.*
>> You need to use an active audio filter to single out the one you're
>> interested in, possibly along with a low frequency spectrum analyzer.
>> What you have done is thrown a plate full of meatball sauce at us and
>> challenged the group to find "the spice."
>
>I tried a few different filters on the recording but couldn't find the right
>frequencies to amplify or drop. Anyway I didn't really expect anyone to be
>able to make a 100% diagnosis from it, but I thought I'd try. It was kind
>of fun recording and listening to my driving so it wasn't a total waste of
>time :)

You might be able to isolate the sound with your computer.

I'm trying to think of some audio signal-processing software I had
once. Anyhow, you get "similar" to a scope trace on your screen, and
can freeze-frame and cut-out the sections of audio you don't want, so
you only keep what you do want.

The secret here is the beat-frequency. If we knew what the beat
frequency is, it would be a simple task to mute all the audio around
it ( well, not simple, but doable ) and just isolate the noise in
question. You can't go by frequency chopping, because no doubt, this
sound covers a broad spectrum of audio frequencies, so you have to go
by beat frequency.

It is an interesting CHALLENGE. A good educational one at that !!!
You are somewhere on the planet, we are somewhere else, we have a
sample of a signal from MARS, and we need to isolate one particular
noise on it, that is mixed in with all the other noises.

This is one of the best challenges I have =ever= seen on a Usenet
Post. I only don't know how _exactly_ to solve it =yet=. But it can
be done by someone with the right software, of that I am certain.

Lg

"Lawrence Glickman" >

> It is an interesting CHALLENGE. A good educational one at that !!!
> You are somewhere on the planet, we are somewhere else, we have a
> sample of a signal from MARS, and we need to isolate one particular
> noise on it, that is mixed in with all the other noises.
>
> This is one of the best challenges I have =ever= seen on a Usenet
> Post. I only don't know how _exactly_ to solve it =yet=. But it
can
> be done by someone with the right software, of that I am certain.
>
> Lg
>

Perhaps SETI could be of help?