I am going to try to type this out the best I can, I am a pretty smart guy but I can not type to save my life. I was wondering what the ECU is looking for to turn on the Secondary Injectors(Secondary Flag?) on the TII S4. Such as RPM, MAP, TP, etc, and once the ECU see the correct parameters what basically happens? Does it just "turn on" the secondary injectors or does it change timing, or the pulse to the Primaries?

I currently have an issue with the secondary's not sending fuel when they should I think it is a TPS wiring issue but I want to understand what is suppose to be going on.

 

I believe they kick on at 3800rpm I think its only rpm dependent but I'm sure somebody with more experience can chime in. https://www.rx7club.com/2nd-generati...ectors-970641/ heres a thread I found on the topic.

 

On the NA car it's only dependent on RPM (90% confidence). On the turbo, I'm not sure...why ask? Just curious...

 

on the stock ecu, they turn on at 3800 rpms with load. and basicly it halfs the primarys duty cycle, then the secondary picks up what was taken off the primary. then they both continued to increase in duty cycle together.

typically an issue with the secondary hesitations can be due to poor grounds. or if someone has messed with the engine before, the metal "ring grounds" for the ECU harness not being bolted down properly to the top of the rotor housing, can cause the secondarys to not come on at all, or do other bizzare things.