In diesel engines the combustion pressure waveform represents an ideal tool for detecting combustion anomalies. The cylinder pressure signal contains a lot of information about the condition of the engine and the combustion efficiency. It can also be used as identification of mechanical wears in the cylinders. There are growing demands for condition monitoring of diesel engines, and therefore the reconstruction of the cylinder pressure using a non-disruptive, externally mounted acceleration transducers measurements will be an aid in this work. Unfortunately the pressure is not easily measurable outside a laboratory environment, simple methodologies are therefore requested. This paper describes the theory and applications of "Time Domain Technique" [1] and the non-linear filtering technique known as Complex Cepstrum to reconstruction of the cylinder pressure