Mystery exhaust rattle - need help

[H-man]

I have a '94 Civic . A few weeks ago I started getting a rattle toward the middle of my exhaust system, it has become worse by the week, and is more noticeable at idle or very low speed (Loud actaually). I originally thought it was an internal problem with the cat converter, but upon closer inspection, I think the noise is coming closer to the middle of the b-pipe, possibly in front of the resonator or the resonator itself. (See Attached image at bottom). There are numerous shields just in front of the resonator, but they all seem to be fairly tight. And the hanger rubbers seems to be ok.

However, I got under the car today and shook that area of the system a bit with my hand. I was able to cause some similar noise by doing so. Strangely, after doing that I took the car for a 10 minute drive and there was hardly any noise, almost as though my shaking things temporarily fixed the problem. Then later today the rattle came back.

I'm scratchin my head on this one. Is it possible the shields, although they appear tight, are still moving just enough to cause an issue? There are a lot of shielding pieces that come together at that point of the b-pipe.
I've considered it may be an internal problem with the resonator, but it's damn near impossible to pinpoint EXACTLY where the noise is coming from. Any ideas?

 

[DeathLens]

At idle, the exhaust tends to vibrate and possibly cause rattling noises. When you went under there and shook it, was it hitting anything? If you think it's the resonator, take that out and shake it.

 

[AyyCookie]

Motor Mounts.


Sent from my Frame Bangin' using Coilovers.

 

[H-man]

At idle, the exhaust tends to vibrate and possibly cause rattling noises. When you went under there and shook it, was it hitting anything? If you think it's the resonator, take that out and shake it.

Didn't seem to be hitting anything. Unfortunately I can't take the resonator out, it's welded into the middle of the long b-pipe.

 

[H-man]

Motor Mounts.


Sent from my Frame Bangin' using Coilovers.

You're saying the vibration from worn motor mounts would cause a vibration in a specific area of the exhaust system? I haven't noticed any extra vibration throughout the car in general.

 

[DeathLens]

Oh ok. I thought it's separated like aftermarket systems

If it's the motor mounts, then you'll most likely feel the entire car shake/vibrate.

 

[R3dline]

sounds to me like the heat shield around the cat. check it .

 

[H-man]

sounds to me like the heat shield around the cat. check it .

All the heat shields seem to be solid. Albeit they are all held on with 16 year old rusty hardware.

 

[R3dline]

i thought that too, mine was broke loose just enough it rattled, when you would look at it, it all looked fine. jack it up and take another look. try to pry it with a swrewdriver and see if its has come un welded

 

[H-man]

i thought that too, mine was broke loose just enough it rattled, when you would look at it, it all looked fine. jack it up and take another look. try to pry it with a swrewdriver and see if its has come un welded

Yeah I think that's a good idea, I'll get back under there Friday and take another look. If it's not a shield I would think it's gotta be an internal piece broken off inside the resonator. I don't think it's a rusty b-pipe issue because I'm not feeling or hearing any exhaust coming from under the b-pipe shields. My wallet is hoping this is a simple fix.

 

[R3dline]

if its messed up somewhere, just order a new cat back on ebay for the time being, for like 150 shipped -shrug- and if you dont want it loud put the silencer on it.