Very black exhaust residue... running rich?

[shizznats]

I noticed lately that there is a LOT of very black residue in my exhaust tip, and i have light smoke which comes out of the exhaust after i shut off my car for a bit. I guess my car is running rich.. what is the common cause of this in a BD? thanks.

[Sarra]

Could be you're burning a little oil, but that's usually a blue smoke.

[decke48]

all subarus run rich. but thinks that can cause it is a leak in the intake, an exhaust leak before the upstream o2 or the upstream o2 its self is going bad. a bad cat.
a smoke machine is nice to own to check for leaks in intakes and exhausts. a scan tool with live data will look at the o2 if the upsteam o2 should cycle lean to rich (under .500mv lean over .500mv rich). a bad cat can be checked by the downsteam o2 the higher the milvolt the less the cat is reducing emisions.

[deadlydave]

It sounds like you're running rich. Decke48's got everything covered that I could think of, and other stuff I would have missed.

[shizznats]

ok just cleaned the MAF sensor in case it was thinking it was getting more air than it really was. it looked really clean when i got it out though so I doubt its that. If the car is running rich, shouldnt i be getting a CEL P0181 or something that tells me there is a too rich or too lean mixture?

[decke48]

well it needs to exceed 1.5 time federal specs before a CEL will come on. i had a leak in my intake and it was running real rich. it was running 37% rich before i even got a CEL.