The presence and distribution of liquid fuel within an engine cylinder at cold start may adversely affect the hydrocarbon emissions from port-injected, spark ignition engines. Therefore, high speed videos of the liquid fuel entry into the cylinder of an optical engine were recorded in order to assess the effect of various engine operating parameters on the amount of liquid fuel inducted into the cylinder, the sizes of liquid drops present and the distribution of the fuel within the cylinder.A 2.5L, V-6, port-injected, spark ignition engine was modified so that optical access is available throughout the entire volume of one of the cylinders. A fused silica cylinder is sandwiched between the separated block and head of the engine and a “Bowditch-type” piston extension is mounted to the production piston. The Bowditch piston has a fused silica crown so that visualization is possible through the top of the piston as well as through the transparent cylinder. Fuel is injected into the primary intake port and the secondary intake port contains a butterfly valve so that the amount of swirl in the cylinder can be modulated.High speed (up to 9,000 frames/sec) videos of the fuel entering the cylinder under motored conditions were recorded as a function of engine speed, manifold pressure, injection timing, swirl, cycle number, and fuel type. Significant variations in the amount of liquid entering the cylinder, the size of the liquid drops and the distribution of the fuel within the cylinder were observed.