So I have a Mini Cooper 2012 Base Model. My car will only start if I step on the gas. There is black smoke and some gas coming out form the exhaust. I ran a code scanner and all it shows is the ambient air sensor, but would that affect the engine? I thought it was only for like AC. My coolant sensor looks fine but I’ll double check. Thank you for the help

  • "There is black smoke and some gas coming out form the exhaust." Do you mean gasoline? If so, are you sure it isn't liquid water or water vapour (which are normal when the exhaust system is cold) ? Dec 27 '20 at 9:26
  • Was the check engine light on? What exactly was the code #? What exactly was the code translation? "Ambient air sensor" is NOT the entire message. You aren't telling us everything. How many miles/KM on the vehicle? How long has the check engine light been on? How long has this no start problem existed?
    – zipzit
    Dec 27 '20 at 9:35

A faulty ambient air sensor may very well cause the problem you are having at startup. Clear the code before troubleshooting further.

The ambient air sensor has nothing to do with a/c. It monitors outdoor temperature so that the computer remaps the air-fuel mixture in the cylinders accordingly. The idea is that cold air is more dense and contains more oxygen than warm air. If your sensor inaccurately reads the outside temperature as colder than it really is, the computer will deliver too much fuel to the cylinders. Black smoke will come out of the tailpipe.


Re: Ambient air sensor = Mass Air Fuel Sensor? , if so that will throw off all your Air/Fuel ratio causing lean/rich condition.

Also something to consider ,is your engine affected by carbon buildup ,where by the valves are carboned up causing misfire? .It affects engines that do have direct injection technology. Black smoke = rich condition (too much fuel) , carbon = low volume of air from valves

Did you floor the accelerator on startup?

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