The ignition and combustion characteristics of a scramjet combustor equipped with a tandem cavity were rigorously explored and evaluated in this study. The experimental setup, a direct-connect scramjet combustor constructed at Pusan National University, is a blowdown type facility employing a vitiated air heater (VAH). It adeptly simulates conditions at altitudes of 20–25 km and flight Mach numbers between 4.0 and 5.0. Our experiments were strategically conducted under off-design conditions to elucidate the distinct combustion dynamics facilitated by the cavity. Notably, auto-ignition was absent, necessitating the use of a micro-pulse detonation engine (μPDE). An increase in the equivalence ratio, triggered by elevated injection pressures of hydrogen gaseous fuel (GH2), revealed diverse combustion phenomena. These included the cavity shear layer flame and the jet wake flame, distinctly captured in Schlieren imaging. Additionally, the study investigated wall static pressure profiles along the isolator and throughout the scramjet combustor. Results indicate that as the fuel injection pressure and equivalence ratio increased, a consistent pattern in the formation of the combustion zone was observed, irrespective of the ignition position. However, variations were noted in the downstream wall pressure distribution within the combustor and at points of significant pressure drop.