Diesel exhaust is a complex mixture of combustion products of diesel fuel, and the exact composition of the mixture depends on the nature of the engine, operating conditions, lubricating oil, additives, emission control system, combustion parameters and fuel composition. In a diesel engine, NOx (NO & NO2) and PM (Particulate Matter) are the most critical constituents for the emission legislation. In order to control the PM emission of diesel engine and comply with increasingly stringent exhaust legislation, more information is required on the components and genesis of PM. In general, PM from diesel engines is classified into two fractions: Insoluble Organic Fraction (ISOF) and Soluble Organic Fraction (SOF). In this experimental study, a series of 13 mode ESC cycle were run on a light duty diesel engine after optimization of combustion parameters (Injection Pressure, Injection Timing, Multiple Injections, EGR rate, etc) in successive tests and PM component was analyzed. An unconventional and innovative method to check the contribution of each mode by taking PM individually in all 13 modes was employed. Unlike the usual ESC 13 mode sample method, PM in the exhaust was separately sampled in this research under every test mode. The overall objective of this is to utilize current understandings presented from methods of experimentation to develop a new way for the reduction of 13 mode ESC cyclic PM by per mode analysis. This was done to further reduce the PM by optimization after analysis and meet the emission norms. The effects of injection timing, rail pressure, multiple injections and EGR rate on PM composition of diesel engine are investigated in this study. The percentages of ISOF and SOF contents in PM are markedly changed with changes in combustion parameters. Results provide insight into the effects of combustion parameters on combustion and emissions in this engine and identify areas of potential future emissions reduction.