As one example, a method is provided for controlling a relative amount of air and fuel that is provided to a combustion chamber of an internal combustion engine. The method comprises adjusting a relative amount of air and fuel provided to the combustion chamber during an engine start based on a volatility of the fuel identified during a previous engine start. As another example, a vehicle engine system is provided, comprising: an internal combustion engine including at least one combustion chamber; a fuel injector configured to provide fuel to the combustion chamber; a fuel system operatively coupled with the fuel injector including a fuel storage tank; a control system configured to vary an amount of fuel injected into the combustion chamber during an engine start based on a speed response of the engine during a previous engine run-up from rest and a change in an amount of fuel stored in the fuel storage tank before the engine start.