Abstract　 　　
　We present a systematic study of the pure deflagration model of Type Ia supernovae using three-dimensional, high-resolution, full-star hydrodynamical simulations, nucleosynthetic yields calculated using Lagrangian tracer particles, and light curves calculated using radiation transport. We then evaluate these simulations with various distributions of initial ignition points by comparing their predicted light curves with an ensemble of observed SNe Ia using the SALT2 data-driven model. We find that the rate of nuclear burning depends on the number of ignition points at early times, the density of ignition points at intermediate times, and the radius of the confining sphere at late times. The simulations with few ignition points release more nuclear energy, have larger kinetic energies, and produce more $^{56}$Ni than those with many ignition points, and differ in the distribution of $^{56}$Ni, Si, and C/O in the ejecta. For these reasons, the simulations with few ignition points exhibit higher peak B-band absolute magnitudes and light curves that rise and decline more quickly, which resembles the properties of under-luminous SNe Iax.