Black soot in exhaust. Normal?
 

Hello people,
I am currently in the market for a BRZ. I have been looking around and noticed some cars have black soot in the exhaust and that the oil smells like gasoline. To me, it seems that the car is running rich and that either there is a leaking fuel injector or the piston rings are worn. I just wanted to know if this is normal in boxer engines or if the piston rings are simply worn because the previous owner didn't take care of their car.
Any insight is appreciated :)

Thanks,
oma

is it stock, or does it have headers and a tune?

It runs rich at startup while the cats are warming up. So I would say smell it after the warm up sequence is complete

Every car I've ever owned has required me to clean the tips weekly or else they would be black. Not wet, just dry black powder. I suspect it has a lot to do with my driving habits though. Since switching to E85 in my FRS I have gone about 9000 miles and the tips are crystal clear. I am intentionally not cleaning them to see how long they stay clean.

Normal af.

stock

That I agree on, but its not just a little bit of powder like my other cars, I slide my finger inside and It is PURE black. There's a good amount of it

Good point. Would it be because of the ethanol content in the fuel maybe? Would it be because of maybe the previous owner put low grade fuel inside the tank?

That's the way my stock 2013 FR-S is. Why? Because of a lot of cold starts and short trips.


:iono:


humfrz

Ethanol burns cleaner so it doesn't leave deposits as much. The black you are talking about, is it wet or just dry powder? If it's wet I would assume it's oil and I would stay away, if it's dry I would say it's just from running a little rich. But probably just someone who doesn't bother cleaning the tips and drives the car in open loop a lot.

So would you say it is because of oil dilution? I don't even want to take the risk on this car anymore. I don't think there's anyway for me to check if its an injector, worn engine or having tons of short trips.
I think its important to mention that the car is also sitting in a show room at the dealership, so I doubt it goes through many short trips.

its powder. What do you mean by "open loop a lot"

as previously stated, its probably from when your cats are cold

Short hop driving soots them up. Or a bad tune.