Custom build 1990 Mustang stock injection need help

[EagleMark]

The SFI may effect idle or could be turned off, not sure how newer cars work but the LT1 is only SFI in idle very low RPM, then batch fire. Just not enough time to fire each injector at higher RPM with cars of this era.

Are newer cars sequential at more then idle RPM? I was told that idle emmisions was only reason for this at time, had no impact on drivability or performace cause there's just not enough time to turn on/off injector for each cylinder.

[RobertISaar]

The SFI may effect idle or could be turned off, not sure how newer cars work but the LT1 is only SFI in idle very low RPM, then batch fire. Just not enough time to fire each injector at higher RPM with cars of this era.

Are newer cars sequential at more then idle RPM? I was told that idle emmisions was only reason for this at time, had no impact on drivability or performace cause there's just not enough time to turn on/off injector for each cylinder.

don't suppose you can throw 2 injector circuits on a scope and confirm this? seems odd that it would switch out. my 95 MC should be SFI at all times, but i don't have a scope to confirm it.

i made a thread on 60V6 about the differences in single fire MPFI, double fire MPFI and SFI.... it wouldn't bother me one bit if SFI had yet to be invented.

[Six_Shooter]

From many years of SFI discussion it seems that most manufacturers switch between SFI and batch fire at around 3000 RPM.

[EagleMark]

There is a Constant in TunerCat $EE I do not have in TunerPro $EE which would tell us when it happens in an LT1 called :

"Individual Cyl. Fuel Trim Disable %TPS"

[RobertISaar]

individual trims are used for commanding slightly different BPWs for each cylinder, not a SFI->MPFI transition. IIRC, EE has two individual cylinder trims, one for idle and one for non-idle? that constant is probably used for switching between the two.