Quote Originally Posted by 1project2many View Post
I have not complained about the time I've invested here nor am I complaining about the lack of time for the projects I'd like to do. I am simply stating facts. Since forums don't convey context clues well, and since I don't know you well enough to interpret your post accurately, I will ask up front if this is an invitation to become uninvolved in this project. No harm no foul either way.
I invite your input! I feel collecting information and sharing information is a benefit to all.

Let me try to do a chronological order of my research in an attempt to think thru the options of building an underhood TBI ECM EFI System.
1. Use $8D with resistors in series for PnH injectors. My research revealed the DRP's are not the same TBI / MPFI.
2. $89 seems like a good path forward. The research revealed the '7727 has only one injector driver for PnH? $89 would require development of both a .xdf & .adx.
2a. I have not researched $3E.
3. $A8 & $8B seems like a good path forward, both .xdf & .adx are developed. The 1228708 ECM has two PnH injector drivers.

Based on my research, the Memcal cylinder select voltage will configure the DRP rate of injector fire. The Quad 4 will fire the injectors once every DRP, which is the same DRP rate as a TBI EFI System.

Maybe the 4 cylinder Memcals for both 1227727 and 1228708 have the same Memcal cylinder select voltage?

Some design considerations I think are important to me in an EFI system. Very low cost is highly desirable! The service parts (sensors, ignition system, and computer) installed in an EFI system should be OEM and unmodified. I think from my EFI design considerations, saying the underhood TBI system is really just a Quad 4 EFI system, with a custom programmed PROM Chip appeals to me. Being able to set up a scan tool, like an AutoXray or something similar, for a Quad 4 EFI vehicle application also appeals to me.

From what I've looked at $A8 & 8B have very nice Timing and VE Tables compared to the $42 TBI Timing and VE Tables.

I hope this lets everyone know where I'm coming from.

dave w