Hi, first time poster. I just bought a 92 civic cx with 129k miles, good condition, runs good. As far As I know the only after market mod is the fart cannon. I am pretty sure that the engine was tuned by the previous owner.

I have been driving it for a week or so, the mileage seems on par with specs at 35-40 mpg. I noticed the other day that there wasa bunch of black dust on the tail gate. When the engine idles, the exhaust is fine and the engine sounds normal. no smoke or gas comes out of the exhaust, but when I rev the engine, black smoke and gas spew out of it.

With my limited knowledge of engines, I deduce that there is incomplete combustion and the fuel injection need to be adjusted

I am going to put some fuel injector cleaner in next time i fill my tank and then maybe some fuel system cleaner, but not sure what else I should do about this.

If any one could help it sould be greatly appreciated.

 

Fuel system cleaner always helps, and try higher octane gas if you haven't

 

I will do that, thanks

I dont know what octane the previous owner put in, but last fillup , i put in midgrade.

I think I need to change the oil, clutch and brake fluid too, but I dont think that will make do much.

thanks

 

try disconnecting the battery for a minute. If that did not seriously improve the problem then try a bad injector or fuel regulator.

 

Are you sure it's gas coming out of the exaust and not condensation? If it's raw fuel, it's going to kill your cat. converter in short order.

 

well, i think i figured it out. It is the oxygen sensor.

i dont think it has ever been replaced and it is 30k overdue.

I think that makes sense, considering that the problem stops after the car has been running for a while. It is only when it starts up after sitting for a few hours that the fuel spews out.

I have talked to several poeple about this and each of them say it would probably be the oxygen sensor.

My question now is where can I get one cheap? I have looked online and the cheapest is about 150 wing wangs for the bosch sensor, is that the best price there is, or are there alternatives? I love this car and Only want the best for it!

Thanks again for helping a n00b out.

 

Ebay probably or try an autozone ya know they usually got the 4 options and brands to choose from and stuff.

 

ok, thanks Omni

 

I have heard bad things about the bosch, get denso

 

i have the same car and model, my check engine light went on and it was my oxygen sensor. I asked around too and the cheapest i found was $175. i said the hell with my 70 hp d15b8 and got me the d16z1 for 350 installed. good luck finding a cheap one.