This report documents the investigation of fuel injector fault detection methods for a seven liter diesel engine. This effort was conducted for the Tank Automotive Research Development Engineering Center (TARDEC) Condition Based Maintenance (CBM) team. The task of this investigation was to develop algorithms capable of real-time detection of injector misfire events. The purpose of this task was to enable TARDEC's Engine Control Management (ECM) research and development efforts to evaluate the technical feasibility of integrating automated on-board condition monitoring algorithms with future ECM monitoring and control operations. During this investigation, it has been shown that multiple techniques can correctly detect and identify injector cylinder misfiring. Each individual technique has its own advantages, and this investigation focused on signal processing methods that would be suitable for embedding in an engine controller or processor. The following list includes six injector fault analysis approaches that were evaluated for this effort: (1) Injector signal analysis; (2) Cylinder head vibration analysis; (3) Crankshaft speed analysis in time domain; (4) Crankshaft speed analysis in order domain; (5) FFT classifier selection technique; (6) Time domain classification technique. This paper only highlights the crankshaft speed order domain technique. In conclusion, an order domain inspection of data collected by the crankshaft's existing encoder system provides valuable information that can be used for injector fault diagnostics. By monitoring the amplitude of the crankshaft's low order content relative to the suggested fault detection window, injector health can be classified. If a faulty injector signal is diagnosed, the phase of the one-half order can be compared to the clustering in Figure 7 to determine the cylinder that is most likely distressed. The order domain approach showed the great potential for on-board vehicle implementation. The approach demonstrated the capability of detecting individual injector misfires on the seven liter diesel engine over the (30 lbs-ft @ 700 RPM) to (560 lbs-ft @ 2100 RPM) operating range when tested on an engine dynamometer. Furthermore, this approach demonstrated the ability to correctly identify the specific cylinder location of the faulted injector. This approaches requires a TDC/1 PPR or 360 PPR encoder signal for synchronization or the camshaft speed encoder signal, along with the basic hardware and software for algorithm implementation. Among other factors, the extent to which fuel line clogs or worn injector actuators are relevant faults may dictate the reliability of this approach in a fielded environment.