ABSTRACT: This paper describes the detection of diesel engine cylinder misfire utilizing the engine vibration measurements. The proposed technique depends on time-frequency analysis (TFA) of the measured engine surface vibration. The combustion induced vibration and noise of engine is mathematically modeled and the vibration signals are simulated for fired and misfired engine. Both simulated and measured vibration signals for fired and misfired are analyzed by fast Fourier transform (FFT) in frequency domain to identify the signals′ frequencies. Then, they are analyzed in time-frequency plane. To investigate the engine fire and misfired according to firing order of the engine cylinders, the time-frequency plane is converted to the corresponding crank angle-frequency one. From crank angle-frequency analysis of the engine vibration the engine misfire is detected from the measured vibration signal as well as from the simulated one. The experimental results show that the engine misfire can be detected by time-frequency analysis of measured engine surface vibration.