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-   -   Cause of my horrible exhaust note and ses light? (https://mustangboards.com/modular-4-6l-tech/25401-cause-my-horrible-exhaust-note-ses-light.html)

LOOT 07-24-2007 08:41 PM

Cause of my horrible exhaust note and ses light?
 
lol...
I think I may have figured out why my exhaust has been sounding like crap. Ever since I put my Mac o/r h pipe on I have been forever trying to find out why I keep getting this horrible "BAP BAP BAP BAP BAP!!!!..." sound when I would get on the throttle or at certain rpms. I thought it was a leak at the manifold but the more I listened it sounded like it was coming from the rear. I took the car on about a 500 mile trip and it kept sounding worse and worse then the cel came on. Autozone read it as a PO133 front o2 drivers side sensor. I just climbed under it and pulled it out and noticed my drivers side muffler. Do you think this was possibly causing my cel to come on because of a back pressure issue? Why did the muffler blow out like this? I noticed the other day when you would tap on it you'd hear a rattling sound like there's rust inside. Do you think maybe the baffles inside rusted out or something and were rattling in there enough to make it blow out? Oh well I love the MAC sound so I guess it's time to order a new catback.
http://img384.imageshack.us/img384/6079/p1010095wh1.jpg

http://img384.imageshack.us/img384/7025/p1010092wr5.jpg

cobra1923 07-25-2007 05:37 AM

holy cow, the hole itself shouldn't cause an issue...but if the baffles inside (I think MACS have a honeycomb substance in the muffler) have rusted and crumbled, there could be some blockage that would cause an issue. Once way to find out, you're going to be replacing the catback from the looks of things, I'll bet the CEL goes out with the new exaust.

the more I look at the pictures, the more it looks like you ran over something or kicked something up to do that. Those look like cracks vs the normal rotting. I'm sure it sounded terrible.

LOOT 07-25-2007 01:54 PM


Originally Posted by cobra1923 (Post 279478)
the more I look at the pictures, the more it looks like you ran over something or kicked something up to do that. Those look like cracks vs the normal rotting. I'm sure it sounded terrible.

Well a new catback is on the way. I dont recall hitting anything but who knows. I drove for hundreds of miles the other day at 80 mph so I guess maybe that blew it out. lol.. Yeah it does sound terrible. When you hit about 2000 rpms the thing rattles like crazy. I think the whole insides of these are gone. I know the other day I tapped on them and you could hear rust rattling around in there. I stuck my finger in the hole and shined a light in there and didn't feel anything like baffles so I guess they're all gone. It's basically just a hollow can. The catback was on there when I bought the car and was pretty rusty then so I guess it had been on there a few years plus I make a lot of short trips in the car and I hear that's really bad for exhausts. No wonder my car sounded so bad. Now with the hole there it's REALLY bad. heh... Well brenspeed has me one on the way so it will all be good in a few days. :Woot:

venom 07-25-2007 02:25 PM

I had flowmasters which I like to call rustmasters. Not thier fault but non stainless steel mufflers rust from the inside out thats why I will only buy SS. Remember there is condensation inside the exhaust at start up.

LOOT 07-25-2007 02:41 PM

Yeah I wish I could afford some ss right now but I'm pretty much broke. Really though in all honesty you save money buying stainless systems if you plan on keeping the car more than a couple of years. I think MAC is probably not made as well as flowmaster but I love the sound and they don't cost as much. I just paid a little over 300 for my MAC catback and the flow catback is around 400. Like you said though venom they are gonna rust anyway unless you go stainless. I just think flows have a little more to rust away than the macs. I guess that's why the macs are louder. :D

LOOT 07-29-2007 07:03 AM

just a quick note to everyone (that cares...lol..) that I got my new mac catback on yesterday and it sounds AWESOME!! I now feel like an idiot for all the posts I made thinking I had a manifold leak. That nasty sound I was hearing was the fact that ALL the inside baffles of both of the mufflers were completely GONE! I couldn't believe when I took a look in the old ones. They were just hollow cans. hehe... No wonder it sounded like crap. Car runs 100% better too.

v6'stang 07-29-2007 08:06 AM

awesome, congrats on gettin'er fixed up!! did the CEL go out??

LOOT 07-29-2007 08:57 AM


Originally Posted by v6'stang (Post 280254)
awesome, congrats on gettin'er fixed up!! did the CEL go out??

Thanks! Well it went out for a while but just came back on again last night. It's not running rough yet but I think that passenger front o2 sensor may be bad after all. I have a bosch replacement but I wanted to be sure it was really bad before replacing it. I read that a vacuum leak could possibly trigger that code too so I'm gonna go out now and check all the hoses and stuff.

v6'stang 07-29-2007 04:22 PM

yea i've heard the same bout the vaccuum leaks. sux that didn't fix ur problem, but at least the shitty sound is gone!


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