Can you start a car with the ecu removed?

In general, a car will not start without an ECU (Electronic Control Unit). The ECU is the brain of the engine management system and controls various functions such as fuel injection, ignition timing, and emission control. It also communicates with other systems in the vehicle such as the transmission and the instrument cluster. Without an ECU, the engine will not receive the necessary signals to operate correctly and will most likely not start.