This paper aims to conduct a study of the problems associated with the wear of the needles and fuel injection nozzles utilized in diesel engines. The wear found on the needles is mainly associated to impurities in the fuel oil and microcavitation occurred due to high pressure in the phase of the air compression for combustion of the combustible fluid. These pressures associated with the temperature and the fluid velocity results in the occurrence of vaporization, which releases shock waves that cause damage to the affected surface. The impurities solid particles from the fuel oil cause problems inside the nozzles as obstruction of the holes and wear on the needle tip and nozzle seat surface. These failures affect in the atomization of the fuel, since the deterioration of the internal passages of the nozzles interferes in the spray formation and in the end passage of the fluid. For the execution of this study it will be used digital microscopic analysis in specimens that suffered damage, in order to investigate the effects of fuel property, and the temperature conditions and pressure in the formation of the wear on the needles and injector nozzle.

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