190E '88 2.3 8v. I have lately begun to smell gas when the engine is on, especially in cold mornings. To be a little more exact, the smell seems like unburnt "crude" gasoline that indicates a rich mixture. I can smell this odor with the windows open but I never never smell this with the engine off, only with engine running. The smell is not too bad, but I can notice it and ask my relatives and friends if they can smell it. Most of the time they say no but a few have complained that my car smells when runs.

Besides a rich mixture, what could be other causes? Oxygen sensor bad??? a leak in the fuel delivery system? Any ideas on unburnt gas smell while car is running will be appreciated.

Oxygen sensor bad is a possibility, also check/clean/regap or replace your sparkplugs.
Start with the sparkplugs.

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

The engine runs rich on cold mornings, and it takes a few minutes for the catalyst and O2 sensor to get hot enough to go into closed loop operation at which point HC emissions should be very low.

I wouldn't worry about the situation. If there's something wrong, you will find out on your next emission test.

When was the last test and how did it do?

Duke

Old plugs, or the cold start relay. Is this a daily driver and do you use a good brand and grade of gas? Go to http://www.autobahnpower.com/products.asp?recnumber=92 and buy the fuel system cleaner advertized. It worked mircles on my 79 450SLC and my 99 C280. The 450 which I just bought had only been driven 5K miles in the last 19 years, I put a can of 44G in an almost empty tank filled it with 93 octane and ran it almost empty, fuel economy improved from 16mpg on the highway to 20mpg and from 10mpg in the city to 18mpg. One tip after you have driven the car let is sit for at least 12hours as this products "stick" to carbon buildup and melt is away. Also driver 50 %ighway and 50% city and run the tank down as empty as you feel comfortable with.