The research work focus on the occurrence of incylinder peak pressure variation and fuel spray characteristics on piston seizure. The study has been carried out for direct injection diesel engine of heavy duty off-highway application. The well optimized and normal combustion results into the peak cylinder pressure variation within 3.5 bar to 4 bar, whereas the abnormal combustion signposts the peak cylinder pressure almost double of normal combustion. The research work has been carried out to study the effect of different peak cylinder pressure variation and its effect on the start of piston seizure. The three different range of peak cylinder pressure variation have been selected for the study. The selected range of peak cylinder pressure depicts normal to abnormal combustion characteristics. The effect on piston motion dynamics and start of piston seizure has been carried out successfully. This also reflects how the intensity of peak cylinder pressure variation affects the time factor for the occurrence of piston seizure. The second part of the research analysis revels how the abnormal fuel spray characteristics results into the piston wear and seizure. The fuel spray and combustion cavity interaction has a significant role in engine performance, emission and reliability of the power train system. The advance fuel injection timing and improper fuel spray-cavity interaction leads to the fuel flooding. The study successfully demonstrated the relation between fuel flooding and piston erosion. The research work also revealed the significance of fuel flooding on lubricating oil film wash out phenomenon and its contribution in piston wear and start of seizure. Thus the present research work helps to bridge the gap between understanding the effect of peak cylinder pressure variation and fuel flooding on piston seizure occurrence.