The objective of this paper is to study an experimental evidence of gasoline ionization by a magnetic field.Results could be understood as an experimental evidence of what has been concluded, but not scientifically explained completely, since almost eight decades from underlying theory on the action of magnetic fields on liquids, confirmed empirically in the last three decades by better performance of mobile sources using efficient fabricated magnetic fuel optimizers; Ethos MAX Power Super Fuel in England and Fuel Optimizer in Argentina, to mention only two efficient magnetic devices, as well as many magnetic fluid conditioners patented in the last three decades in USA, and the results for Carbon monoxide (CO) and hydrocarbons (HC) emissions obtained from gas analyzers of two ADC (Automotive Diagnostic Centres) in the city of Cartagena, Colombia, in 2008.The results are also experimental evidence of the influence of hydraulic changes in flow conditions (section enlargement) before the action of the magnetic field, in the whole process of optimizing the fuel combustion.Moreover, the results show that the magnetic field action on the fuel is more efficient when magnets are within the conduction hose than that when placed externally to it.An experimental set up was used for measuring DC current through standard gasoline RON 87 under five different conditions; no magnets with or without altered flow conditions, with 2400 gauss neodymium magnets within the conduction hose with or without altered flow conditions and with neodymium magnets placed externally on the conduction hose.Successive values of 50nA, 320A, 780A, 2.7mA and 4.8mA were measured, suggesting ions increase, and consequently electrical resistivity decrease.Four apparent electrical resistivities (and apparent electrical conductivities) were calculated and important different grades of magnitude were found.