Black soot on rear end
Thread Starter
Melting Slicks
Joined: Sep 2005
Posts: 2,625
Likes: 1
From: Rhode Island
Originally Posted by VetteDrmr
How long are you driving your car on a given trip? With that much water coming out (and this is the season to see it), I'm wondering if you're driving your car long enough to get your hi-flow cats up to temp. If they're cold they won't do their job very well and you could start seeing that carbon sooting.
It would be interesting to see how bad it gets if you go run your car for 15 minutes or so, leave it running, wipe the rear off then go drive again. If the soot goes away then we can start aiming at the startup enrichment/cold cats scenario.
HTH, and have a good one,
Mike
It would be interesting to see how bad it gets if you go run your car for 15 minutes or so, leave it running, wipe the rear off then go drive again. If the soot goes away then we can start aiming at the startup enrichment/cold cats scenario.
HTH, and have a good one,
Mike
Race Director
Joined: Sep 2003
Posts: 13,550
Likes: 6
From: Now in God's Country, the Big Sky, Montana!
Cruise-In 7-8-9-10 Veteran
St. Jude Donor '06-'07-'08-'09-'10-'11-'12
Did you get your problem solved yet? Which mods did you do before this happened? How about you Aloha?
Safety Car
Joined: Jul 2005
Posts: 4,275
Likes: 4
From: Vancouver WA
Originally Posted by RonJ
My 01 does the same.
I get 30mpg on the highway and don't use any oil.
I also don't worry about it ....
RonJ ...
I get 30mpg on the highway and don't use any oil.
I also don't worry about it ....
RonJ ...
My 99' gets a little inside the taillight area. It's just little specs of black. I think it's probably brake dust because I have never seen black smoke, and this is when it was bone stock.
Drifting
Joined: Nov 2003
Posts: 1,506
Likes: 0
From: N East fl
Originally Posted by cbx1047cc
I'm not talking about a little brake dust. I mean 1/8" black spots. It's only on the rear and it's all over the exhaust tips as well. If I let it sit there and idle when I first start it, there will be a mess on the ground, wet and black like you put black paint in a pump bottle and sprayed it. I can see the water droplets coming out and they are black from picking up the carbon inside the pipes. Still think it's brake dust?
I have a 01 coupe that does the same thing. But I think mine only does it when I;ve been at higher RPMS.
Le Mans Master
Joined: Feb 2006
Posts: 5,267
Likes: 40
From: Phoenix AZ
My yellow 00 does the same. Has the Corsa cat back. Black soot crap all over the back when I get on it alot. Just did a dyno run at XMS and the A/F ratio was 12.5 at WOT. Im sure its just that.
Drifting
Joined: Oct 2001
Posts: 1,463
Likes: 0
From: Lancaster CA
Cruise-In III Veteran
Originally Posted by mkiv808
Must be running a little rich from that tune? 
I'm the original owner and my 2003 coupe would get black soot all over the rear fascia...from the day it was driven off the lot.
Last year I added LG Pro LT headers, high flow cats, Borla stingers and had it dyno tuned at A & A Corvette Performance in Oxnard, CA....Charlie Tuner said it ws pig rich. I haven't seen the soot since before the tune. It still sucks a little dust & dirt now, but no soot.
My guess is you are still running rich after the tune.
-dave
