7. The Atomic EFI’s power module is secured to the firewall with four mounting screws. The module can be mounted underhood (away from direct exhaust heat) or in the passenger compartment. The ECU wiring and handheld are shown plugged into the module at this time. In addition to the power module, the Atomic EFI requires a square wave ignition signal to trigger, such as an MSD ready-to-run distributor or a CD-style ignition like the MSD 6-series.