It is well known that approximately 23% to 25% of nucleons found throughout space are in the form of Helium 4 atoms. The distribution uniformity indicates that these atoms were formed in the very early universe. In addition, trace amounts of Deuterium, Lithium 3 and Beryllium 7 are also uniformly distributed. These elements are evidence of a process known as primordial nucleosynthesis based on historical work by G. Gamow, H. Bethe and A. Sakharov and more recently by N.D. Schramm [10]. Residual deuterium is a sensitive test for this period and the goal of the work is to determine when residual primordial deuterium originated and re-evaluate limits on cosmological parameters. Specifically, the WMAP [3] and PLANCK [13] missions concluded that baryons could not make up more than 0.046 of current density. The primary variable is the baryon/photon ratio that is a function of expansion temperature and radius. PLANCK concluded that the baryon/photon ratio was 6e-10 and WMAP’s value was slightly lower. The author explored an expansion curve called R1+R3 based on values found in a model of the proton [5][7][Appendix 1]. The expansion curve is similar to the concordance model [4][3]. The temperature decreases from big bang values until He4 forms at 8e8K but He4 fusion energy causes the temperature to spike and this affects the baryon/photon ratio. The temperature spike is accompanied by a radius increase. Both of these affect the baryon/photon ratio. The radius increase allows the baryon/photon ratio to be 6e-10 with a baryon fraction of 0.5 of current density. The other half of current density is dark matter. Temperature and radius histories that include He4 fusion energy appear to be missing from the literature.