MegaSquirt is a general-purpose aftermarket electronic fuel injection (EFI) controller designed to be used with a wide range of spark-ignition internal combustion engines (i.e., non-diesel engines.) MegaSquirt was designed by Bruce Bowling and Al Grippo in 2001. History The Megasquirt's predecessor was the EFI332 project, led by Bruce Bowling and Al Grippo. EFI332 development started around 1999 and culminated in the release of about 200 kits in 2000. The system used a 32-bit MC68332 microcontroller from Motorola. A very steep coding, electronic design, and tuning curve prevented the system from gaining wider acceptance. The designers then decided to simplify the EFI332 design, and focus on managing the fuel injectors (the EFI332 was also designed to control the spark plug ignition system if so desired). This was the basis for the first MegaSquirt (MS-I). The MegaSquirt was launched on September 15, 2001. Current Products For a more detailed cross-reference of the features available within the MegaSquirt range of products, see MegaSquirt product cross reference Hardware The assembled controller takes input from several sensors in order to manage the fuel injectors, including a throttle position sensor (TPS), exhaust gas oxygen sensor (EGO or O2 sensor), MAP sensor, Crankshaft Position Sensor, optional Camshaft Position Sensor, Intake Air Temperature sensor (IAT), and a Coolant Temperature Sensor (CLT). The default calibration is configured to match common General Motors type, although the controller can easily be recalibrated to use nearly any sensor on nearly any engine. As the product line of Engine Management Systems has evolved through multiple hardware and firmware revisions, at least when referring to the Legacy/DIY oriented MegaSquirt Systems (kit type ECUs) it is difficult to be specific about the capabilities of any particular MegaSquirt without knowing three things: microcontroller, printed circuit board and firmware versions. As for the commercial/refined MS3Pro and MSPNP lines, this is far simpler as these systems were engineered to 'just work' and not aimed at the DIYer. Microcontroller The version 1.0 MegaSquirt used an 8-bit Motorola MC68HC908 microcontroller, and all versions of the main board support this processor. The later MegaSquirt-II processor upgrade daughter card includes a 16-bit MC9S12, and is a step up from the original MC68HC908 processor MegaSquirt. The current Megasquirt-III uses a 16bit MC9S12XEP100 processor running at 50 MHz which includes a 100 MHz RISC core. Printed Circuit Board The first group buy of printed circuit boards for the original MegaSquirt-I was in 2001. These