AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 29)

Page 29 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
Crank Sensor
Crank Sensor Basics
The crank sensor is used to calculate engine speed, ignition timing and injection phasing
angles. It senses a toothed wheel (reluctor wheel, reluctor ring, etc.) and converts this pattern
into a voltage/frequency signal that the EMS uses for basic calculations. Either on its own, or
combined with the cam position sensor, it is the most important input to the system. There are
two basic types of crank sensors, variable reluctance
(VR or “mag”) and hall-effect.
VR Sensor raw voltage signal