Quote:
Originally Posted by spork2367
Continuation of the discussion from the for sale thread:
What does the secondary injector module actually do?
As determined by Marc's testing, all ECU's are interchangeable with the correct PROM. Which would lead me to believe that either the circuitry exists in both ECM's, or it's done entirely through the PROM.
One would think, that with the proper programming, a simple wiring change should be able to eliminate the secondary injector module from the car.
On another note, I have one of the DIYautotune megaquirt LT5 ECUs. When ordered, I had to specify 1990, or 1991+. They cited an internal wiring change between the two. Does anyone know if this is due to the secondary injector module? Why does the stock ECU handle both with a programming change, but the megasquirt requires internal differences to the circuitry?
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The LT5 ECM and engine controls are a derivative of the L98 logic. The ECM ONLY controls the secondary injectors by energizing the secondary relays sending power to the secondary injectors. It essentially provides the ground
(-) for energizing the secondary modules. The pulsewidth for the secondary injectors is controlled or “shared” w the primary injector signal from the ECM. Once engaged, the ECM basically cuts the pulsewidth by 50% so two injectors now share the fueling needs of the motor.
So NO, a simple change would not do the same thing. The secondary module substitutes for injector drivers.