ok, so i know this is becuase my cars running rich. but i fixed the o2 sensor which we though was the original problem. then i found out my cat was working so i installed a brand new high flow cat. still getting the black reside. what else is wrong?

 

maybe your burning oil...My Friend had a 95 hatch and his bumper was full with black crap because he was burning oil

 

If its still there, then you might still be running rich. Your ECU could be going, I know on my old accord it started doing all sorts of weird stuff when the ECU went nuts. Is it throwing any codes?

 

Have you checked the oil? Sounds like what it is. On my friends car it did that and he has to replace the rings so I would check into the rings and head gasket.

 

Black is fuel. Your car is spitting unburnt fuel out the tailpipe. Thats whats causing the buildup...could also be carbon deposits...clean everything out see if that helps.

 

Hope you plan on changing rings yourself if that's the case. No one in my area will touch the rings. I don't know why, but they all suggest just buying a used motor for 500 and installing it, which is what I am doing. Labor for rings is like 700 anyways, why not pay they labor torwards an engine replacement? :/ Just my two cents.

 

when i used the seafoam on my car i noticed my tailpipe was black because it was spitting out all the crap seafoam had cleaned up

 

i found that running an aftermarket exhaust will always produce carbon dust on the rearof the caras the silencers do not catch it all.