AMP EFI MS3Pro - Secondary Injector Timing Table; Staged Injection

7.2 Fuel Settings 7 ADDITIONAL ITEMS: BEYOND BASIC FUEL AND IGNITION CONTROL
Injector timing is specified as a function of RPM and fuel load. Most engines run best if the injection timing
is completed before the valve opens, to allow the fuel to vaporize. So, if you have a cam card with an “Intake
valve opens” spec, you can use this and the “end of squirt” setting to ensure the fuel injection finishes before the
valve opens. An injector timing value of 360 degrees, when used with timing set to “end of squirt”, would finish the
injection event just at the intake valve is starting to open, as shown in the diagram below.
7.2.2 Secondary injector timing table
This timing table is used if you have enabled a secondary set of injectors, either with the Staged Injection or Dual
Fuel menu. While these injectors may need the same timing as the primaries, secondary injectors that fire in an
upstream direction or in an air horn often need different timing.
7.2.3 Staged injection
Staged injection allows the use of one set of small injectors for low-load and/or low RPM operation of the engine
with the ability to engage a second set of injectors at higher load and RPM when the primary set of injectors
would otherwise reach their maximum operational duty cycle. The MS3Pro’s staged injection function supports
staging equally between the primary injectors and secondary injectors during staged operation as well as staging
completely to the secondary set of injectors. You may either use the standard injector outputs A through H on a
four cylinder, or use injectors I and J in batch fire on engines with more than four cylinders. Sequential injection is
not available for engines with more than eight cylinders.
If you have enough outputs to use timed injection on the secondary injection, the Secondary Injection Timing
Table is enabled (in addition to the standard injection timing table), so the user must remember to tune secondary
injection timing separately from primary injection timing.
AMP EFI MS3Pro manual version 1.202, firmware 1.5.0, 4/21/2017 Page 152