ok so i have a 95 civic with a rebuild d16z6 but since i got the car before the rebuild my car smell like gas fumes if it wasnt burning the gas correctly. And im having like 13-16 mpg with full tank i only get 175 mile. My car dosent loose any power drives good and everything but fumes is killing me sometimes it only smells when i turned it on and when im driving it dosent smells but if i get out of the car it smells a little bit but my mpg are too low. im thinking those two things are connected the mpgs and fumes it might be for the same problem. Could it be my canister that is place on my firewall or my pcv valve or my canister that is below my IM thanks

 

Sounds like it is running rich to me. A bad evap canister would not cause you to get 17mpg. Any codes thrown? Could be bad timing as well. Check and see if there is a MASSIVE buildup on carbon in your muffler (and possibly on your bumper as well). If the car were running rich, unburnt hydrocarbons would be flying out your tailpipe, accounting for the gas smell and bad mileage.

OR you could have a leaking fuel line, if the smell is from under the hood.

 

Check for leaks. Do a tune up.

 

tune up is already been made complete tune up i replace my O2 sensor as well theres no leaking lines and yes im running rich i thought it was the canister cuz one of my frinds replace it on his acura cl and the fumes went out but his mpg never change when the canister was bad. and no i dont have any codes or anything

 

Where is the gas smell coming from? Since you are running rich, I am assuming it is your tailpipe. There are many things that can affect the A/F ratio... Was this problem present before replacing the o2 sensor as well?

 

this problem has it since i bopught the car so it hasnt change and yes it comes form the tailpipe

 

Are you sure your CEL is actually working? I.e. the bulb. Im sure an emission problem dealing with gas would throw a light. Especially if you have a leak in the gas system. Pressure would be off etc. DO you hear the release of pressure when you unscrew your gas cap?

 

yes i hear the realesa of pressure when i release the cap and i know for a fact that my cel light works cuz i disconnected my map sensor i dont remember for what reason and my cel light was on when i turn on my car so yeah it is working

 

Throw some seafoam in it lol helps a lot in mpgs. Throttle response. Smoother accelaration. Cleaner idle. Just over all performance. Done it to 3 of my hondas running like champs now

 

yeah but sea foam wont take away my gas fumes from my exhaust and like i said its rebuild with less than 20k miles in it and as far as i know sea foam its to clean all the **** that is in the valves pistons etc and mine supposed to be clean cuz i replace it with new ones

 

You need to figure out why your car is running rich. Could be that the new o2 sensor you put in is bad. Could be bad timing (you should really, really check your timing.) Could be any number of things. Have you cleaned the grounds?

 

well before i install my O2 sensor it was still running rich the timing was done cuz i put it wrong so a shop fix it for me and still the same grounds i believe they are clena cuz my engine bay i always cleaning it i like to have as clean as possible