right when i hit vtec i get a lot of black smoke, im going to replace the O2 sensor and see if that helps...im looking to do a swap soon. (my motor has 278,000 mi) any other suggestions? any info would help. thanks.

 

Once VTEC engages, it's normal to have a little smoke come out of the exhaust. When the crossover takes place, the ECU does dump more fuel to make up for the excess amount of air coming into the cylinder.

 

its coming out pretty thick.....and when idling it spits little drops of black on the pavement sometimes.

 

I think you should save that money going towards the O2 sensor for the swap. 278k is a lot on that motor. Not worth fixing anymore. What made you jump to the O2 sensor as a problem? Is it because you get CEL?

 

no im not getting CEL. I just thought the O2 sensor would help with running too rich.

 

the black smoke is no biggie. thats fuel.
but the drops coming out of your exhaust is probably condensation. just water vapor. do you have stock exhaust?muffler? my old coupe smoke black in vtec w/128,000. its nothing. also, do you have a adjustable fuel pressure regulator?
-Chris

 

i have a custom cat-back with a can-style muffler.....and i do not have an adjustable fuel pressure regulator.

 

Is raw fuel coming out of your exhaust or water?

 

the only thing that comes out of my exhaust is black drops of moisture sometimes when its idling, and it smokes a lot when i get on it hard.

 

its just running to rich, I know your not getting a CEL, but not everything throws a CEL if it's bad, I just got my TPS light to go off after 2 TPS's, I just replaced the whole throttle body, i was dumping hella black smoke when I was in limp mode from it running so rich, but everything is fine now.