I've been having this issue for a while now, say a month.. generally on a hit start, sometimes on a cold one too, the exhaust will be louder than normal.. just loud. like it has a leak in the midpipe or something. I've read about the CPS sensors causing this, but it hasn't thrown any codes what so ever, and it's running as smooth/powerful as ever. Next guess, since the loud exhaust is accompanied by a complicated rattle, that it's the cats. but once again, no codes, and it doesn't always do it.
I got it on a lift and looked around underneath, the cats are quiet as can be when you bang on them, hot or cold, and the only thing amiss appeared to be that the exhaust was tapping on a little cross brace in front of the mufflers.. that could account for the rattle.. or at least part of it.. but what do you guys think?
The longer it goes on, the more I think it's gotta be the cats. how can i find out for sure?
Just b/c there are no codes that does not mean that the CPS is not going bad. However, when I had my SS exhaust installed, after about 2 weeks the exhaust "settled" and the exhaust dropped a little and was sitting on a bracket and it sounded like sh!t. Brought it back to the Indy, they tightened it back up and gone. So, its possible a bracket broke or maybe early sign that your CPS is going bad.
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2003 M5
2006 E55
2002 E46 M3 / Carbon Black / SMG (track car - heavily modded)
2008 Escalade
Last edited by Michael_s; 3rd November 2007 at 19:12.
If a CPS goes bad, there's no early sign about it. They are binary - they either work or they don't, although sometimes they fail intermittenly for awhile.
They will light up your Check Engine light quickly. Loss of power plus plus Check Engine light plus weird loud noise. First time it happened to me I thought the exhaust system had fallen off; I actually stopped and looked under the car.
I've had 3 go bad, but the replacements have all been fine.
Happened to me today... I've been tossing some cps codes recently, but haven't gotten to the swap yet. Today all of a sudden the car sounds like a muffler fell off. Down on power... felt like it was hitting on 7 cylinders. Really pathetic. Even the vanos was making a funny noise. Drove like this for about five miles, but no SES light. Haven't bothered to check for new codes.. pretty obvious what the problem is!
I am having a very similar problem. Upon start up when I press the gas the car sounds like it has an exhasut leak at the Cats....with a ratle aded on....no services lights at all. After a couple minutes of driving it goes back to normal....I have full warranty still....any advice on what I should do, or say when I take it in,,,,,, also after driving it hard, when I pull into my garage I smell alot of sulphor on the outside of the car.....I only run Sunoco 94 here in TO......can it be the cats?
I'm really thinking more and more that most of my problem is just the exhaust hitting that little crossmember right in the middle of the car.. i need to get it in for that and then we'll see how it runs.. that rattle is noisy as hell sometimes.
Happened to me too about a month ago. SOunded like I suddently have a leak on my exhaust system as the exhaust sounded really deep. Then my SES engine light came on.
I determined it to be a CPS going bad. A week later the problem went away on its own. Now the beast is running well again and I havent really changed anything.
So it appears to me that I do have CPS going bad. I will order CPUS soon and get them replaced. I infact have a post on this issue about a month ago.
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Dan
Supersprint Headers, Tubi Rumore Plus exhaust, Dinan CAI, Defi Heads Up Display, Strong Strut front anti-sway bar, Powerchip 93 S/W, Euro Arm rest, Fikse Profil 5S Rims; Goodyear Eagle F1 GS-D3, Polk Audio Tweeters, Boston Acoustic Speakers, Integrated 60gig Video Ipod, HiDef DICE Radio iPod interface, Icelink, Rouge Engineering Short shifter, StopTech Big Brake Kit, TC Design rear sway bar brackets, HID 8000k fog lamps, 8000K low beams, Euro clear corner HID headlamps, Mark IV Nav, Lamin X films, Predator ICE LED AE, Valentine 1, M20 Blinder Anti Laser, TEC cup holder, All LED interior lights, LED footwell lights, LED trunk lights, Ultimate Cup Holders, Hella TC-400 Tire Pressure Monitor System, etc.
I'm really thinking more and more that most of my problem is just the exhaust hitting that little crossmember right in the middle of the car.. i need to get it in for that and then we'll see how it runs.. that rattle is noisy as hell sometimes.
If you have an aftermarket exhaust (especially a tubi) that is the problem...
__________________ 2002 Carbon Black/ Caramel lightly modded - SOLD to board member
Biding my time...
I've got a strange exhaust problem.
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