Manifold Pressure/Vacuum Sensor: Description and Operation

PURPOSE
Sensor provides a signal to EZ control unit, relating to engine load, to assist in ignition timing calculations.

LOCATION
Integral part of EZ control unit.

OPERATION
When starting engine, manifold pressure sensor is checked for short-circuit or open circuit. Firing angle corresponding to full-load curve (1800mbar) is output if pressure is below 750 mbar (short circuit) or above 1250 mbar (open circuit). Since pressure line from intake manifold might be disconnected or kinked, even if electrics of pressure sensor are fully operational, a pressure of less than 770 mbar must be present at pressure sensor as soon as 0° throttle switch has closed and after 2 seconds have elapsed. The firing angle corresponding to full load will again be output if this is not the case.