What is this Black Residue From Exhaust

**j nix** · 06-08-2011, 06:59 PM

I started my car before opening the garage door all the way and later when I raised the garage door, I found 2 8" diameter spots of black residue on the door. Can anyone tell me why my exhaust is exhausting black residue, what it is and how to fix it?

**Knight** · 06-08-2011, 07:17 PM

Chances are it's just condensation exiting the tail pipes. You could check all your fluids and make sure you aren't burning/losing any, but I'd bet on the condensation over anything else.

**Smittro** · 06-09-2011, 04:56 AM

Most cars experiance some sooting as a normal biproduct of combustion..

However, if the sooting is ecsessive(sp) it could be a sign of poor combustion due to incorrect AFR's (air fuel ratio's), bad or incorrect tune, vaccume leaks, etc, can contribute to over sooting..

I would say if you're not getting a "service engine soon" light, and it's seems to be running normal, (no unusual fuel consumption, no big clouds of black smoke) then the condition is likely normal..imho

**j nix** · 06-09-2011, 01:48 PM

I have a Diablo Sport tune in it that changed the air fuel ratio, but it drives a lot better with the tune. It runs great actually. I just had it on a dyno for 2 power poles the day before. They got on it pretty good there. But it is running good and no check engine light, so I think I will forget about it until I have a problem. Thanks guys.

**JayTA98** · 06-10-2011, 09:12 AM

Originally Posted by j nix

I have a Diablo Sport tune in it that changed the air fuel ratio, but it drives a lot better with the tune. It runs great actually. I just had it on a dyno for 2 power poles the day before. They got on it pretty good there. But it is running good and no check engine light, so I think I will forget about it until I have a problem. Thanks guys.

I also get some of the black stains but is on my exhaust. The car was tuned by Frost and its been running fine.

**PFM** · 06-10-2011, 10:23 AM

Are you still running stock exaust with cats or? Probally the Diablo Sport Predator Performance Tune you have installed has alot to do with it. I tried a handheld tuner once and it didn't have enough programing options to do an accurate tune. I tried it while the car was on a dyno to see what its stored program would do to the A/F and it couldn't get it close. I suggest getting a better tune via HP Tuners or Frost. I returned my handheld.

**JayTA98** · 06-10-2011, 10:53 AM

Originally Posted by PFM

Are you still running stock exaust with cats or? Probally the Diablo Sport Predator Performance Tune you have installed has alot to do with it. I tried a handheld tuner once and it didn't have enough programing options to do an accurate tune. I tried it while the car was on a dyno to see what its stored program would do to the A/F and it couldn't get it close. I suggest getting a better tune via HP Tuners or Frost. I returned my handheld.

Agree.

**j nix** · 06-11-2011, 04:56 PM

I guess that makes sense. I thought Diablo sport was a good one. You can do live logging and adjust the parameters yourself. I might try that first. I was waiting to get a dyno tune after I get headers.