Electron spectra were measured at GANIL with different heavy ions (C–Mo) and various charge states q (q=6–39) at fixed projectile velocity v (v=19 atomic units, 9.2MeV/u). A projectile dependent broadening of ion induced KVV Auger electron peaks from carbon targets was observed. From this broadening, one can deduce a mean “electronic temperature” of the heavy ion induced track at the corresponding Auger decay time (10fs). We compare the measured temperature values to the predictions of an inelastic-thermal spike model, which takes into account the electron–phonon coupling. The model underestimates the experimental values, but reproduces the increase with ion charge.