Metallic Noise
 

My 8 started making a metallic noise when I start to accelerate. It sounds like it is coming from the cat or downpipe. It is really annoying. I am thinking about upgrading the exhaust and I am hoping that will fix the problem. But, I'm only doing cat back so I am sceptical. So, i am looking for any ideas on how to fix it, or if anyone has had that problem.

Any input would be appreciated.

Any more description on the sound? Is it a tapping sound, vibrating, grinding? Unless you have some metal in your muffler or if your muffler is loose and vibrating, I dont think the catback is going to change anything.

Heat shield is a good bet. Wait till is cool under there and then climb under and start banging on stuff until you find it,
but the heat shield is still a good bet if you would classify this as a rattle?

What kind of sound
 

It is like a vicious rattle near the cat. It starts and stops sporadically. I think I could have hit a speed bump and damage the heat shield. I will take a look. If the damage is bad, how much would it cost to replace one?

too much stock cats are real expensive better off getting a midpipe

Would I fail em emissions if I did that? The rotary engine isn't know to be the easiest to pass emissions.

Here in Cali we smog our cars every 2years. So go it the midpipe and when smog time comes pop the old cat back on.

If its the heat shield rattling, you can prob fix it. If there is nothing rattling but more of a marbles in a can sound, you could have a clogged cat. If it's clogged, its covered under federal law for 8 yrs. Got mine replaced :)

I will look into that. So, it looks like it is either the heat shield or the cat. I am gonna work on it this weekend. Thanks for all of the input

This weekend? It's going to be cold and rainy my friend :) Like stated above, tap around underneath to try and hear whats vibrating. Where in MA are you? If your close and want some help I'm willing to help.

I live in Tewksbury. It is right near lowell. That isn't that far from Somerville. What days are you free. I get home from school by three everyday.

Today or tomorrow would be the best days since it is supose to rain later this week and throughout the weekend. If you are available today, I could possibly be up there by 6pm the latest. If you could have it jacked up by the time I get there, we can get rollin. Then we can grab some food after. Let me know

Yeah that sounds good. I am going to need to borrow my friends jack. Hopefully he is home. I do have to one that came with the car though. If this sounds good, I send you my address via a message.

i have the same noise - i can't figure out what it is - even after i replaced my cat, still makes the noise. It sounds like you are sucking metal shards up a vacuum cleaner tube, only does it under acceleration, the harder you accelerate (esp from a stop) the worse it gets. Its infuriating - i have started searching the MIAC issue, but i don't think its it. I have a couple other issues now that are cropping up, id love it if it turned out that mu 86k mile '8 needed a new engine before the 100k warranty is up. knowing my luck it wont be, and then at 100,001 miles it will freaking blow on me.

originally i thought it was the heat shield, never checked it out, let me know if you figure that out to be your issue.

Also, when i close my trunk, it will make the noise, only one time though, until i run the car again. WTF?

Resolved
 

JMC23200 and I looked at the car today. The problem is that a few of the tac welds on the heat shield are broken, which allows it to vibrate at high rpms. It is an easy fix which involves getting it rewelded.

Thank you all for the help, and I can't wait to be able to hear the smoothness of the engine for the first time.
:D:

^thnx same prob i have

Yeah, the sound was kinda thrown off while in the car. It kind of sounded like it was comming from the engine bay. Once you stand outside the car and rev, you can clearly hear it around the cat. Any local exhaust shop or mechanic should be able to tac weld it back on to fix the rattle or take it off and tac weld a new heatshield on for you. Shouldn't cost more then $60. Or you can drop the cat yourself and give welding a try :)

dougsears - is this the sound you had?

http://www.youtube.com/watch?v=hzOYZ...=youtube_gdata

because if it is, then i'd be relieved that's all my noise is.

No, that is not the noise he had. Very similar except it wasnt as loud or as frequent. His only happened while revving high. Jack up the car and slide underneath. Take a screw driver and start tapping the cat all over from front to back and side to side. If you hear rattling, then look at the tac welds and see if they are broken were you hear the rattling. It's very easy to spot especially if its that bad. If your not sure what to look for, slide under your car and take a bunch of pics and Im sure we can spot it for you.

Edit: The tac welds are about 1/2 - 3/4 the way to the top of th cat. The heatshield raps up over the cat.

schiraldi, I just read your other post in a different thread that says you changed your cat and now there is no CEL. It is very possible your cats internals broke giving you the marbles in a can sound and now there are still some peices in the exhaust. You can always take of the exhaust from the cat back and give it a good shake to see if you can hear itor get anything out. Or you could buy the new exhaust and be done with it :)

jmc - i thought the same thing that it might be residual crap from the cat, AND i thought that when i had it checked i told em to do that, but nope - i wish i had my own lift :( anyway, your solution is exactly what i was thinking, i wanna go with a good aftermarket anyway, but i don't have the cash right now, or i don't want to spend it, rather. thanks for your answer -

how positive are you that its the exhaust, because thats what i was thinking / hoping it was.

by the way - know of anyone selling an aftermarket exhaust? cheap? any suggestions in general? i love the sound of the borla and the greddy se or sp2, but i cant afford paying too much, and i'd prefer not to worry about burning my shrouds. - what to do, what to do.... or should i jsut buy an oem catback cheap off of someone, or just dump the shit out of my current oem?

AP FTMFW!!!!!!!!!!



I have a stock R3 exhaust I could sell ya. You would have to take off your shrouds though to fit it

^^^ hmmm - i may be interested. price?

oh and jmc - i think i jsut put two and two together - the CEL going off around the time i replaced my cat may be a coincidence - i ahve recently discovered that my ssv is bad - causing a knock etc, and i looked this up and came across the following:

"Exhaust & Emissions Hesitation and/or a lack of power can be caused by the secondary shutter valve (SSV) in the intake manifold becoming stuck open due to carbon build up. This may occur with no Check Engine light illumination but eventually the light will illuminate. There is a cleaning procedure and a revised SSV to fix the problem."

my engine code was the follwoing:

"P2259
secondary air injection system control |B| circuit low."


i think, while the cat was obviously bad, it wasn't the cause of the CEL - does this change your diagnosis at all?

I'll have to get back to you on price. I have yet to pursue selling it so I have to look up the worth. But, I will be selling lower than the value. If you are interested, I can get you a price tomorrow