We present transport measurements under pressure on the (TMTSF) 2FSO 3 salt from P=1 bar to 8kbar using a helium gas pressure cell, in order to clarify the pressure-temperature phase diagram of this compound. The interest in this TMTSF salt comes from the existence of non-centrosymmetric tetrahedral anion with a permanent dipole moment related to the presence of the fluorine atom. Two types of disorder can be involved in the metal to insulator transitions at low temperature: one due to the orientation of the tetrahedra and the second to the position of the fluorine atom inside the anion. For all studied pressures a semiconducting phase occurs at T ≈ 90K via a very sharp transition. At lower temperatures, the activation energy decreases as the pressure is increased. At last, the resistivity saturates at P=8kbar from T=80K down to 10K where the metallic state is restored. This new study shows that phase diagrams derived with the use of the clamped pressure techniques should be revised.