Patent ID: 7762234

Claim:
A method for operation of a fuel delivery system in an internal combustion engine having a fuel system including a lower pressure pump, a higher pressure pump fluidly coupled downstream of the lower pressure pump, a solenoid valve coupled between the higher and lower pressure pumps, and a fuel rail fluidly coupled downstream of the high pressure pump comprising: stopping said internal combustion engine with said solenoid valve in a position that allows communication between said lower pressure pump and said higher pressure pump; indicating a fuel system leak based on a fuel rail pressure response; in response to the indication and before a subsequent engine start, the subsequent engine start occurring after stopping the internal combustion engine, adjusting the solenoid valve to a position that prevents communication between said lower pressure pump and said higher pressure pump; and differentiating whether the fuel system leak includes an internal or external leak based on fuel pressure response occurring after the solenoid valve is adjusted.