Comment Re:Dumb idea (Score 1) 98
It's probably the fact that motors are made to dissipate large amounts of energy. The issue with the EMP gun is that, A.) Most cars are made of metal, which would shunt the moving electrical field, and B.) an electric motor would convert an induced current into a torque differential. So, depending on the polarity, an EMP which manages to get around the metal box is just going to be converted into a small acceleration or deceleration.
Because motors of the size necessary to move a vehicle deal with moving electrical/magnetic fields, the control circuitry must be able to withstand voltages far in excess of the rated voltage of the motor. What happens when a wheel locks and the armature comes to a sudden stop? The magnetic field collapses, with a sudden increase in voltage. Electrical engineers know this, and design accordingly.
The bigger issue is what an EMP would do to engine control components in a typical ICE vehicle, because the wires leading to the ECM are typically not shielded, and the ECM's themselves are only built to deal with 18V.