AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 260)

Page 260 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
Staged Injection
The AEM EMS has up to 10 individually controlled injector drivers (depending on the system).
EMS-4 systems have 4 injector drivers. By default, they are assumed to be driving primary fuel
injectors. Alternately, they can be defined as secondary, or "staged" injectors. These can be
activated on an as-needed basis or by a user defined ratio between the two based on engine
speed and load. The staged injectors are fully sequential with user defined, independent
phasing.
User Definable Options for Staged Injection
Fuel Difference Map
Units: On/Off Description: When ON then the Fuel Difference Map is map is used to determine
the % of fuel that will be routed through the secondary injectors.
Injector Min
Units: uS Description: If the calculated injector pulse (not including the battery offset injection
correction) is below this value, no injection is performed.
Injector Duty Max
Units: % Description: This determines the maximum pulsewidth duty to the primary injectors
when staged injection is being used. Once primary injector duty exceeds this, the EMS
automatically puts all additional fuel to the secondary injectors. Typical value is90%
Staged Flow Ratio
Units: % Description: Multiplier for staged injection. This tells the EMS the flow rate difference
between the secondary injectors versus the primary injectors. If you have the same number &
same size of secondary injectors as your primaries, this value is 100%. If you have secondary
injectors that flow 3 times the primaries, the value is 33%. If you have 4 times secondaries, but
only 2 (on a 4 cyl), the value should be 50%. Remember to account for the total primary flow
rate (flow x number of injectors) and the total secondary flow rate (flow x number of injectors).
This value must always be 100% or less, i.e. the secondaries must flow as much or more than
the primaries.
Staged Flow 2 exp
Units: Multiplier Description: Multiplier used on the Staged Flow Ratio option to allow low flow
secondary injectors. This is only used when the maximum flow rate of the primaryinjectors is
greater than the maximum flow rate of the secondary injectors. Note: Avalue of "0" does
nothing.
Diff Switch Input
Units: Switch Input Description: This assigns an input channel to activate the Fuel Difference
map.