AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 265)

Page 265 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
injectors. This sets the injectors to run only on the primary injectors until the base injector duty
cycle exceeds the Injector Duty Max option. Once that has occurred, the fuel in excess of
Injector Duty Max is routed to the staged injectors. The time set in the Injector Min option
keeps the system from quickly switching back and forth between the two if the duty were to stay
right at the Injector Duty Max threshold. The staged injectors will stay ON until the base
injector duty cycle decreases below Injector Duty Max.
The second method for mapping fuel to the staged injectors uses the Fuel Difference map
and the Injector Duty Max threshold in unison. The Fuel Difference map allows you to
specify what percentage of fuel should be delivered via the staged injectors. The number
entered into this map is the percentage of total fuel that will be delivered to the staged
injectors. This can be set based on load and engine speed and gives the best control. To set
this up you need to put the appropriate values into the Fuel Difference map and turn the Fuel
Difference Map option to ON.
Additionally, there is a switch input available, called Diff Switch Input where the staged
injection can be disabled from the cockpit. If this is used, it needs to be assigned to a switch
input. If only the software operating criteria is used, set the Diff Switch Input to Switch is
Always On. This says the switch is always ON so only the software criteria is used. It is
important to remember that the Injector Duty Max limit will still be used so set that value to a
reasonable number.
You can view and/or log the actual base injection times with the Fuel Inj Pulse Pri and Fuel Inj
Pulse Sec channels. You can view and/or log the actual injector duty cycles with the Fuel Inj
Duty Pri and Fuel Inj Duty Sec channels. To view the current battery Injector offsets, use the