well i just got my twin loop muffler instaled and i looked at the old piping and its HORIBLE BLACK CRAP all over it.... all on the bumper as well...

now i dont know if its coming out of the motor... or if its residue that could be stuck in the resonator and catback piping just coming out of the pipes still...
cause the motor was blown when i got the car so it probably has pleanty of crap blown thru the pipes...

i just dont want this black crap to pack up my new twinloop muffler... i dont know if its a motor problem, or if i should just replace the mid piping.....
i dont think replacing the mid pipe would cost to much from local muffler shop.... tho i dont know if they will touch my exaust because of the deleted cat.... again NOT DONE BY ME... i just dont know if they will touch it or not... id have to go and ask them.
or maybe the black crap is just coming from the motor since the cat isnt thier to absorb that crap/polution... so maybe ill have to replace that as well....
this is what the black crap looks like when i banged the muffler out a bit, plus it was all over the pipes before the muffler as well...





tho the black ON the outside of the muffler is paint...
but my motor doesnt burn any oil or smoke any and good compresion...

WHAT DO YOU THINK COULD BE THE ISSUE?
no cat..
oil residue all in the pipes/resonator..
or worse motor problem...

i dont have a CEL light on at least..

 

It's called carbon build up, it's from the motor running rich

 

you think it could be from a past problem? or current problem....

last milage i got was 34.5MPG
i think it if would be running that rich it should kill my milage shouldnt it? ive been geting constant milage outta this 94civic...

but i guess the O2 sensor could be junked up from the blown motor cause thats one thing i did reuse....
maybe i should try bolting up the other manifold that came with the motor and HOPE the O2 sensor is good..... i just have to cut off some stupid flexpipe off it and paint it up and new gaskets... but i guess it could be a problem...

knowing my luck that build up could have my resonator packed up just as bad.... i just REALY dont want it to pack up my new muffler and start to sound that crapy again!

thanks for your help..

 

Mine has been running rich (damn O2 sensor!!!) and i have the same issue but it's nothing to worry about, just make sure you make some high rpm runs on the highway or something to get that all blasted out nice and good. It's actually recommended by BMW with their cars to make some high engine speed runs to blast the carbon out. so go enjoy the new exhaust note to it's fullest potential.