littlejohn Posted September 12, 2007 Report Share Posted September 12, 2007 Hey guys, I'm wondering if anybody else has seen this; I have a very thin film of black soot in the tailpipes of my car. It's very thin, but very black and fine. The car has over 6000 miles on it, and 3500 of the first 4500 miles was a road trip to break it in, driving carefully, varying speeds etc. It has been driven hard probably 20-30 times taking friends for rides and racing the odd time. The oil has never moved and is crystal clear(not milky or opaque). It runs very hard; I've beaten easily an '07 C6 convertible w/auto (5+ lengths by 100 mph) and pulled even with an '03 Z06 that had a tune (430-440 hp). It idles smoothly and revs quickly and smoothly as well. To me, it seems as it may be rich on the top hence the minor soot, but I thought I would put it out to everyone for input. Thanks. Link to comment Share on other sites More sharing options...
MACHMAN Posted September 12, 2007 Report Share Posted September 12, 2007 Hey guys, I'm wondering if anybody else has seen this; I have a very thin film of black soot in the tailpipes of my car. It's very thin, but very black and fine. The car has over 6000 miles on it, and 3500 of the first 4500 miles was a road trip to break it in, driving carefully, varying speeds etc. It has been driven hard probably 20-30 times taking friends for rides and racing the odd time. The oil has never moved and is crystal clear(not milky or opaque). It runs very hard; I've beaten easily an '07 C6 convertible w/auto (5+ lengths by 100 mph) and pulled even with an '03 Z06 that had a tune (430-440 hp). It idles smoothly and revs quickly and smoothly as well. To me, it seems as it may be rich on the top hence the minor soot, but I thought I would put it out to everyone for input. Thanks. Yes, I have just noticed this for the first time on my car, anyone else? Link to comment Share on other sites More sharing options...
mrfarmdog Posted September 12, 2007 Report Share Posted September 12, 2007 Same here. I posted something about it the other day but I thought is was because I was having some idle issues. Since I reset my PCM the idle issues have gone but I still get the black in the tailpipes. Link to comment Share on other sites More sharing options...
Wolfie Posted September 12, 2007 Report Share Posted September 12, 2007 Same here. I posted something about it the other day but I thought is was because I was having some idle issues. Since I reset my PCM the idle issues have gone but I still get the black in the tailpipes. It is soot. All cars run slightly rich from the factory as a safety. Check your AFR and you will see it is high. Link to comment Share on other sites More sharing options...
croz98gt Posted September 12, 2007 Report Share Posted September 12, 2007 Here are some pictures of my factory exhaust with about 1200 miles on the car. The pics show where the axle backs bolt up and if you look close you can see where the soot has sprayed the underneath of the car. I put the EVO Stage II on the car with only 300miles on it and it was dynoed at 500 miles. At that time the A/F was 10.6 which is RICH. JJ Link to comment Share on other sites More sharing options...
BUCKEYE Posted September 12, 2007 Report Share Posted September 12, 2007 I Installed FRPP axle back the first day I got the car , I dont have any exhaust under the car but it is in the lip of the tailpipe and around it pretty bad,It also dosent take long to get the back of the car dirty, I have white stripes and it shows up and sticks to the stripes pretty good ? Link to comment Share on other sites More sharing options...
croz98gt Posted September 12, 2007 Report Share Posted September 12, 2007 I Installed FRPP axle back the first day I got the car , I dont have any exhaust under the car but it is in the lip of the tailpipe and around it pretty bad,It also dosent take long to get the back of the car dirty, I have white stripes and it shows up and sticks to the stripes pretty good ? tell me about it my car is white.....it is everywhere. Link to comment Share on other sites More sharing options...
ingram4868 Posted September 12, 2007 Report Share Posted September 12, 2007 I thought that OBDII was suppose to be smart enough that if the car was running too rich or too lean that it would adjust the injector duration cycle. Link to comment Share on other sites More sharing options...
MStover1 Posted September 12, 2007 Report Share Posted September 12, 2007 Hey guys, I'm wondering if anybody else has seen this; I have a very thin film of black soot in the tailpipes of my car. It's very thin, but very black and fine. The car has over 6000 miles on it, and 3500 of the first 4500 miles was a road trip to break it in, driving carefully, varying speeds etc. It has been driven hard probably 20-30 times taking friends for rides and racing the odd time. The oil has never moved and is crystal clear(not milky or opaque). It runs very hard; I've beaten easily an '07 C6 convertible w/auto (5+ lengths by 100 mph) and pulled even with an '03 Z06 that had a tune (430-440 hp). It idles smoothly and revs quickly and smoothly as well. To me, it seems as it may be rich on the top hence the minor soot, but I thought I would put it out to everyone for input. Thanks. Keep in mind you have 500hp that doesn't get used that much. A lot of people who bought the Saleene had the same problems as they could never clean them out. I'm sure a performance shop could lean it out for you, however if you ever did lay on it hard I don't know if it would be worth it. Unless your taking it to the track :-). Link to comment Share on other sites More sharing options...
littlejohn Posted September 12, 2007 Author Report Share Posted September 12, 2007 As I suspected, it sounds like a rich condition, which then leads me to the next query. At CNL performance's website, they show dyno sheets from testing their CAI. They state and show the stock car to be rich above 3500 rpm(10-11 AFR) to fuel cut off at 6200. If this is the case, why are some tuners saying its lean stock, and why wouldn't a CAI work without a tune? Not that it would be smart to anyways, but you get my drift. Perhaps it would be too lean in the bottom? Link to comment Share on other sites More sharing options...
2FST4U Posted September 13, 2007 Report Share Posted September 13, 2007 They run fat at cold start. Start it and stand behind the car you can smell the HC's. Link to comment Share on other sites More sharing options...
gt50035 Posted September 13, 2007 Report Share Posted September 13, 2007 At last check, my A/F ratio was at 11.5 at idle. I have about 7500 miles on her, no mods, and yes, I get 'some' black soot inside the tailpipes although not what I would call a substantial build up. I figured it was fairly normal from the excess fuel burn off. Link to comment Share on other sites More sharing options...
2FST4U Posted September 13, 2007 Report Share Posted September 13, 2007 At last check, my A/F ratio was at 11.5 at idle. I have about 7500 miles on her, no mods, and yes, I get 'some' black soot inside the tailpipes although not what I would call a substantial build up. I figured it was fairly normal from the excess fuel burn off. Mine's in the elevens too. People wouldn't notice as if much if they didn't have chrome tips. Functions as built. Link to comment Share on other sites More sharing options...
svtbird91 Posted September 13, 2007 Report Share Posted September 13, 2007 At last check, my A/F ratio was at 11.5 at idle. I have about 7500 miles on her, no mods, and yes, I get 'some' black soot inside the tailpipes although not what I would call a substantial build up. I figured it was fairly normal from the excess fuel burn off. You are correct it is perfectly normal in fact having a completly clean exhaust tip might indicate a lean condition. Link to comment Share on other sites More sharing options...
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