AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 24)

Page 24 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
AEM Four Channel Coil Driver P/N 30-2840
Four Channel Coil Driver Connections
Coil Driver Connections
Coil Driver Connect to
ECU Coil 1 Output EMS-4 harness, IGN 1
ECU Coil 2 Output EMS-4 harness, IGN 2
ECU Coil 3 Output EMS-4 harness, IGN 3
ECU Coil 4 Output EMS-4 harness, IGN 4
Ground EMS-4 harness, PWR GND
Coil 1 Negative Terminal Coil 1 Negative Terminal
Coil 2 Negative Terminal Coil 2 Negative Terminal
Coil 3 Negative Terminal Coil 3 Negative Terminal
Coil 4 Negative Terminal Coil 4 Negative Terminal
CDI Installations
The ignition outputs from the EMS-4 are considered a falling edge fire signal where signal high
is dwell time. A coil driver will invert the signal from the EMS-4 pulling the signal low (ground)
and allowing current to flow through the coil primary windings. Some CDI ignition boxes are
only capable of triggering on the “rising edge” or “Points Trigger” signal. These systems will still
require an in-line coil driver to invert the ignition output to fire on the correct edge. The AEM
Twin Fire CDI system P/N 2820 (8 channel) and 2821 (4 channel) can be configured to fire on
either a rising or falling edge. Applications using an AEM Twin Fire will not require an in-line coil
driver. Contact your CDI manufacturer for more information.