Gasoline engine development has to respond to requirements for fuel efficient and clean combustion. In meeting such targets, the automotive industry has responded with the introduction and continuous improvement of turbocharged gasoline direct injection (TC GDI) combustion systems. Specific challenges to such engines include irregular ignition and combustion events which are rarely met in conventional engines. The paper describes ignition phenomena and mechanisms relevant for the development of such TC GDI engines. Focus then is given to combustion measurement techniques applied for the identification of these spontaneous and riskfull combustion events. As analysis of such ignition events must be done in real, high load multicylinder engine operation, suitable sensors together with measurement and analysis procedures are described. The paper concludes with analysis examples derived from various engine testing situations.