xv, I know it bugs you when people complain about some sound and aren't detailed in their description, so I will try to be most precise. besides, my question really is "should I bring it into a dealership and try to have them address this under warranty?"

ok, the sound: it sounds like a few screws loose being rattled in a tin can. not shaken violently, but more like rolled around rapidly on the bottom, hitting the sides of the can. the sound definitely comes from the rear of the car, and is does not occur cyclically (as it would from a rotating mass, such as the tire, transmission, etc.) so I really believe it's in my exhaust, most likely my muffler.

when the sound happens: very specific rev range: between 3500 and 4000, and only when accelerating. after some experimentation, I found it's barely noticable when accelerating in 1st gear (probably because I don't stay in 1st very long), 2nd gear a bit louder, definitely more noticable in 3rd and certainly noticable and annoying in 4th. I can repeatedly create the rattling sound when I have the car in 4th at around 3000 rpm and I mash the gas pedal pretty good.

it's friggin annoying everytime I hear it!!

so, do you guys think it's some sort of baffle that has come loose in the muffler? or is it possible that maybe some kid dropped a screw or two in my exhaust pipe? does anybody else have this? anything external that you guys think I should look at that might've gotten loose?

or, should I bring my car to the dealership and ask them about replacing my exhaust? I dunno why, but bringing my car to the dealership makes me nervous-- I'd almost rather solve this myself. and something tells me they would rather *not* replace my entire exhaust, but may instead want to cut off my muffler and weld on a new one... which I would not like at all.

all opinions welcome.



( xv, was I detailed enough? )

 

Check if your spare tire wing bolt is tight. A lot of times it's loose and the little flange that holds the tire down rattles.

 

Won't hurt to take the spare tire hold down suggestion just to get that out of the way.
It appears as though you must reach that rpm to get something oscillating in order to make that sound. Exhaust is a good guess. Inspect it to make sure none of the hangers have cracked or broken. This will cause the exhaust to oscillate dramatically when accelerating from a specific rpm as in your case. The reason why it's more evident in the higher gears is because you can sustain that load at that rpm longer.
While you're under there, grab the exhaust system and give it a good shake. Also try thumping on the exhaust with your hand at different places to see if you can duplicate the sound. It's entirely possible some doofus threw something into your exhaust tips. It's also possible that a part of the cat's inards have broken free and has blown its way downstream into the system.
If you can duplicate the noise and you can't easily get the loose bits out, it might be time for a cat back system or find a stock system that someone has just sitting around.
If you can't, you'll need to broaden your search to other areas - drivetrain and suspension.

 

A couple of ideas which may not help directly:

You could take off the muffler (not too hard to do) and shake it to see if loose pieces are inside. You might even be able to shake it without removal. The problem is that you may have to shake it at 3500 rpm if the pieces aren't really loose, just loosely attached.

You can hold 3500 rpm (or any rpm) in the lower gears, under heavy throttle, by braking with your left foot. Can't do this too long, or the brakes will overheat, but it's a good makeshift "dyno" for purposes like this.

Denis

 

If he has the stock exhaust system on (which I believe he does), it might be somewhat difficult to just remove the muffler. Everything from the end of the cat to the tips is one piece and weighs about 45 lbs. Taking it off is not an easy task and once off, it would also be difficult to shake it.

 

i dont want to sound dumb or anything, but maybe someone through something in your exhaust system...ex: pennies or loose change.

I havn't heard of it happening to anyone on the s2k site, but when i was on the eclipse forums it happened to someone. It wont rattle all the time, but when it does it is bad.

Once again, sorry if this sounds like a stupid idea.

 

This topic is pop up more than once in a while now.

There was a lengthly post about a month ago, a pretty good number of MY04-05(including myself) are having the same problem as you. Mine start to rattle from 2500 on up. In higher rpm, the noise of wind, road and the engine itself might help reduce the rattle sound, but definitely most noticeable around 2500-3000rpm for me.

Some said it's the clutch, some said it's the gear syncro', first machanic that rod with me said it's normal.. . I'm waiting for a call from my dealer to bring her in for a tranny surgery. It's scary as h*ll to take the car to dealership knowing that most of them don't know jack about our cars, but it is also annoying as sin to drive with the sound(very embarrassing when I have a guess riding with me as well).

Sorry, couldn't be more helpful, but will keep you all post after all is done with mine.

So.., I'm going in, ..."COVER ME!!!"...

 

Another thought:
Could it be the "ringing" shifter issue?
https://www.s2ki.com/forums/index.php?showtopic=41390

Next time it does it, hold the shifter firmly and see if it stops.

 

^ nah, I don't think it's that. I'll try holding the shifter firmly and see, but I really doubt that's what it is. the sound seems to come distinctly from the rear of the car, like the right muffler, specifically.

thanks for all the suggestions guys.

 

Tritium

I haven't had an s2k muffler apart, but it sounds to me like a broken baffle in your muffler. Usually when they go, they sound just like that.

fltsfshr