The site-diluted Ising model has been investigated using an improved microcanonical algorithm from Creutz Cellular Automaton. For a microcanonical algorithm, the basic problem is to estimate the correct temperatures using average values of the kinetic energy in the simulations of site-diluted Ising model. In this study, the average kinetic energy has been re-described with an expression dependent on dilution x = 1 - p. The values of the temperature have been calculated using the new expression and the critical temperatures have been estimated from the peaks of specific heat for each value of dilution x. The obtained phase transition line (kT(C)(p)/J, p) is in good agreement with functional prediction for the site-diluted Ising model. The simulations were carried out on a square lattice with periodic boundary conditions. (C) 2012 Elsevier B.V. All rights reserved.