Abstract: An emergency ignition system for motor vehicles comprises a high-voltage coil having an input circuit connectible to the vehicle battery and an output circuit connectible to the vehicle distributor for applying high-voltage pulses. The input circuit includes an oscillator generating periodic pulses, and a switch controlled by the oscillator for periodically interrupting the input circuit to the coil and thereby causing the coil to generate high-voltage pulses to be applied to the vehicle distributor. The input circuit further includes a control circuit connectible to the vehicle battery and comprising a voltage-drop sensor for sensing a predetermined voltage drop at the output of the vehicle battery caused by the load thereon when starting the engine, and for producing an enabling signal in response to the predetermined voltage drop to enable the oscillator to output pulses to the switch for periodically interrupting the input circuit to the coil.