An experimental investigation of the PJC (Pulsed Jet Combustion) system in a research engine is presented. The modus operandi is based on the introduction into the combustion chamber of a turbulent plume formed by a jet of rich combustion products issued from an orifice of a generator plug. This study is a continuation of previous investigations performed with the use of, sequentially, a constant volume vessel and a single compression machine. The PJC generator was supplied with a rich mixture via a Bosch injector. Methane was used as a fuel. Pressure records of a piezo-electric transducer were processed by a computer data acquisition system. The investigations were performed for lean combustible mixtures (ϕ=0.625, 1.0) over a wide range of spark advance angles. Direct comparison between the PJC system and conventional spark ignition was made for optimal ignition advance angle. The results have demonstrated that the PJC system is advantageous over the scope of operating conditions under study. The combustion process in the PJC system was evidently faster then that of the spark generated flame, yielding higher peak pressures and shorter pressure rise times. The advantages of the PJC system were particularly prominent for extremely lean mixtures, becoming less beneficial as the equivalence ratio approached stoichiometric proportions.