Why So Rich Fuel

[balln69]

Why am i running such a rich fuel mixture, i have a shit ton of carbon build up or soot or whut ever on my exhaust, and if im sitting still and rev it enough, their is soot all on the ground behind the muffler... jus a new 02 sensor? or something else???

Plz
Peace

[RedRacerCivic]

Originally Posted by balln69

Why am i running such a rich fuel mixture, i have a shit ton of carbon build up or soot or whut ever on my exhaust, and if im sitting still and rev it enough, their is soot all on the ground behind the muffler... jus a new 02 sensor? or something else???

Plz
Peace

Well, it "could" be your O2 sensor giving out, but it can be a number of other things, weak spark, high fuel pressure, leaky injector, too much advanced/retarted timing, loss of compression.

I tell you what, my car right now also runs rich due to a almost dead #2 cylinder(low compression), my car also spews carbon out my exhaust.

If I were you, check your fuel pressure, make sure its good, check your timing, check fuel injectors( if possible) replace the spark plugs and get a new O2 sensor. If it still does it, get a compression test(just pray you are not having the same problem I am with my car)

[johnb16a2]

I agree with all of that but check your air filter as well.

[JimCRX]

How many miles are on motor first off? Do you have an aftermarket exhaust & is the cat. converter hollowed out by chance? If the cat. converter is hollowed out then I'd go with that, depending how many miles are on it...it's questionable. It's not uncommon for higher milage cars to burn rich. If you exhaust is aftermarket and bigger than the stock that could also be a problem. My CRX runs rich, I spit out the black carbon balls when I start it up.

[balln69]

Yeah, umm my kar has 231,xxx miles... lol i have an aftermarket cat-back and i still have the stock cat, i have a short ram air intake also