i have found that if i fill the fuel tank completely full,get a gallon in a proper container so you can top it off for the test,park the car on a grade with front end down,let set for the same time as it normally refuses to start,test to see if there are any changes in starting. now as i normally find a leak i have already got the area that contains fuel cleaned off(i use a steam generator). and in most cases with a small fuel leak the engine will fire right up because no air should enter the fuel system.
got to hunt and find any wet areas.
larry perkins lou ky