Sugar does not dissolve in gasoline, so it sinks to the bottom of the gas tank and starts clogging the fuel filter, fuel pump, and fuel injectors almost immediately. Depending on the amount of sugar added and how the vehicle is driven, it could take a few minutes to a few hours of driving for the engine to stall or not start at all. However, the long-term damage caused by the sugar, such as thick sludge buildup, may take longer to manifest.