Human: Is there a way to tell if my car is running on gasoline or on diesel fuel? Assistant: 
Yes, there are several ways you can tell if your car is running on gasoline or diesel fuel. The most obvious way would be to look at the gas cap and see which type of fuel it has. Another way is to smell the exhaust fumes. Gasoline engines typically have a sweet smell, while diesel engines usually emit a more pungent odor. You could also check the engine oil dipstick for a distinctive color that indicates whether the vehicle is running on diesel or gasoline.