Throttle Switch (Ignition System)

The throttle switch performs 2 functions. Throttle switch has an idle contact and a full throttle contact. The idle contact (closed at idle speed) retards the ignition timing to a certain idle speed curve. The ignition timing will be advanced by the throttle switch (open) when accelerating from idle speed.

The full throttle contact of the throttle switch moves the ignition timing to conform with a full throttle curve. The intake pipe pressure is taken at the vacuum distributor and forwarded through a pressure line to the pressure sensor in the ignition control unit.

The pressure sensor integrated in the control unit provides the ignition control unit with additional load data in the form of instantaneous intake pipe pressure. The ignition timing is advanced in partial throttle range for low fuel consumption and is retarded in full throttle range because of knocking danger. This regulation can be compared in principle with the vacuum advance unit of a conventional ignition system.