I now have about 300 miles on my MS3. After a week of ownership, I finally got a chance to wash and wax it. I also cleaned the chrome exhaust tip which was covered on the inside and end with black soot. It came off very easy, but after a short 5 minute trip there was soot again near the bottom of the tip. I notice when I start it up there is a lot of moisture that comes out of the exhaust and wter vapor, which disappears after the car is warmed up. There is no smoke that I can see. I think it is running rich and causing the soot.

There was a period of time (~50 miles)when the relief valve (waste gate) vacuum line was broken off, because they had broken it off during the motor mount recall. Maybe the computer compensated for the vacuum leak by richening the mixture.

Maybe I should disconnect the battery overnight to clear the memory of the computer, then rehook it up now that the relief valve is fixed. What do you guys think the problem is or is this normal? Are the exhuast tips on your cars black with soot?

Thanks,
Rich

 

you cant stop the soot from happening.
its because of the more 'free flow' exhaust on your MS3.
ur exhuast is more free flowing, which lets more chemicals thru.

i have a magnaflow cat back on my 2.0 sedan, and its gets black in no time.
oh well. at least it comes off easy.

 

I think disconnecting the battery is worth a try since it's so simple to do, but it's a factory turbo car so it's going to run rich.. always.

I don't know of any mazdas that don't get their exhausts sooty on a regular basis. Mine did when it was bone stock, and it's not really worse now that all of the exhaust is replaced with high flow stuff and the car is turboed.

Your car runs rich because it's safer to be on the rich side of things than on the lean side. Don't worry about the soot, just keep scrubbing

 

I've noticed that the bigger the exhaust the blacker it gets. It's not just mazda but all cars out there

 

I had some concerns, but searching found this old post. I picked up a low mileage 08.5 Speed3 a couple weeks ago and the sooty exhaust had me worried. From what others are saying here its normal. I just wish it was easier to clean off without getting your hands filthy! That stuff really is hard to get off your hands too! It seems like it coats the inside of the exhaust cutout on the valence panel and some of the bumper cover too.

Anyway, I'm loving the car. I've put about 500 miles on it so far and just did a full detailing job on it today... wash, clay bar, 3M performance finish (wax). Ready to take some quality photos of it tomorrow.

 

I get soot on my regular 2.3 hatch non turbo, its mainly on the bottom of the exhaust though and not all around. Just use paper towels or shop towels on the cheap. It's not hard at all. Odd thing though it that on my prior Audi S4 twin turbo with Milltek exhaust, I had much less soot.