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Discussion Starter · #1 ·
Been trying to dog this one down. I've read several threads on rattles and exhaust noise and none of them appear to be what I'm dealing with.

07 N/A. I added a clear image hi-flow cat first year I had it (factory replacement was back ordered.) Had the factory replacement done. All was good during the time the hi-flow was on and afterward when the factory cat was back on.

Last spring I put the hi-flow back on because it had a very slight improvement in performance (at least it felt like it did!) and it gave the exhaust note a little more snarl. Life was good again. A while later it started to throw a code related to cat efficiency. Cleared it and it stayed away for quite a while. Came back. Decided to install the o2 sensor bung extender and at the time felt a slight leak between the cat and the header so fixed that at the time (as it could have been the actual cause for the code.)

A few days after that last "tweak" I notice a pinging noise coming from under the car right after starting it up. (I had driven it a couple of times without hearing this.) When I got home I rolled around under it, yanking and pushing on the muffler and pipes. Was not able to hear or detect any contact. Didn't hear it the next several times I drove it, so I thought it was "resolved".

Heard it again last Wednesday. I thought it to be only under acceleration and possibly caused by drivetrain torsion. But I also hear it occasionally during fairly heavy engine braking. It's a distinctive pinging - almost like banging the exhaust pipe with a wire coat hanger.

Anybody else experience this? I wanted to roll underneath it again this weekend but have family coming in for Easter - not sure how much time I'll get to do so.
 

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if its cold and makes the loud ping from the exhaust once it heats up it goes away sounds to me the converter the biscuit inside is starting to break free from the casting . I have heard this a few hundred times. you can lift your car when it is cold hit the converter hard with a rubber mallet or your hand see if it rattles from inside . I know you said its brand new no matter the problem you describes is what I am telling you , ive seen this is an educated guess 18 year experience tech here . check the cat first please post back let us know what it was
 

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Discussion Starter · #4 ·
corey - thanks for the insight. The cat WAS brand new. Only started hearing this after I dropped the exhaust completely (couldn't get a good lever on the downstream O2 sensor so I took the whole thing, cat back - out.) It's not necessarily restricted to "cold" temps, but seems to be less prominent after things have heated up.

I'll try to get under the car in the next few days and "bang" around a bit. I'll let you know what (if anything) I find.
 

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I was going to suggest the same as Corey.

Yogi
 

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Discussion Starter · #6 ·
Got a chance to roll around under the car. I think I'm on my way to a tremendous discovery. That is to say, I'm about to discover I'm a bigger dumb-a$$ that I thought.

I confirmed what I suspected before - it is not an interference between the exhaust system and any part of the body, hangers, etc. A mallet pop on the side of the cat confirmed it's not internal to the cat or near it.

Jerking the tail pipe around resulted in some metallic sounds that seemed to come from the left of the muffler. A bump on that side of the muffler revealed nothing. A few more yanks revealed the noise was from the front - possibly at the "flex" joint just behind the cat?

Nope. But bumping with the rubber mallet reveals it's near the double bend just after the cat. Again, nothing on the outside contacting the exhaust.

Tomorrow I'll drop the exhaust. I suspect I'll turn in on end an a washer is going to fall out . . .
 

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Got a chance to roll around under the car. I think I'm on my way to a tremendous discovery. That is to say, I'm about to discover I'm a bigger dumb-a$$ that I thought.

I confirmed what I suspected before - it is not an interference between the exhaust system and any part of the body, hangers, etc. A mallet pop on the side of the cat confirmed it's not internal to the cat or near it.

Jerking the tail pipe around resulted in some metallic sounds that seemed to come from the left of the muffler. A bump on that side of the muffler revealed nothing. A few more yanks revealed the noise was from the front - possibly at the "flex" joint just behind the cat?

Nope. But bumping with the rubber mallet reveals it's near the double bend just after the cat. Again, nothing on the outside contacting the exhaust.

Tomorrow I'll drop the exhaust. I suspect I'll turn in on end an a washer is going to fall out . . .
Is this the start to the next Fifty Shades of Grey book??? :glol:
 

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Discussion Starter · #8 ·
Fitty shades of "soot" when I dump the exhaust on it's end.
 

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Discussion Starter · #9 ·
Yep. Not only was the noise driving me nuts, it turned out to be one of me nuts.



The ever important reminder to stay patient and pay attention when you're short a piece when you put things together - just as important as when you have have extra pieces.
 

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Discussion Starter · #10 ·
Still amazed at how easier the exhaust is to push back onto the rubber mounts than it is to get off of them. lol
 

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Yep. Not only was the noise driving me nuts, it turned out to be one of me nuts. The ever important reminder to stay patient and pay attention when you're short a piece when you put things together - just as important as when you have have extra pieces.
Having extra pieces/parts just means you're a better engineer than whoever put it together to begin with. You were able to do it with less stuff. :yesnod:
 
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