MSefi.com read only forum (Jan.15,2018)

Hello all,

I got a pretty good deal on a F.A.S.T. throttle body with all the sensors and injectors, so now I'm trying to put together a MS system to control it. I haven't ordered anything yet, I'm just trying to build a parts list right now.

It will be going on a GM Performance Fast Burn 385 motor in a 68 Chevy pickup. I have an HEI right now and plan to run ignition control but I'm not necessarily stuck on the HEI as a means to do that. I plan to get the MS-2 V3.0 so i can use the IAC built into the throttle body, and control ignition.

My question is this:
My throttle body has a MAP sensor built into it, so I want to use that for the input to the MS. That's no problem after reading the assembly directions. But, I am very interested in the barometric correction feature advertised with the MapDaddy add-on. I thought that since I already have an external MAP sensor that I may be able to somehow use the MAP provided with the MS-2 kit as my barometric correction source and save myself a few bucks since I don't need the 4-bar for any other reason? Or is the barometric correction only necessary with FI, not NA?

Hope this isn't a dumb question and that its not already spelled out somewhere for me. I've looked high and low but haven't come across the answer I'm looking for yet.

Thanks!

You can use the internal MAP sensor for baro if you lift its output pin and jumper it to JS5.

Matt Cramer wrote:You can use the internal MAP sensor for baro if you lift its output pin and jumper it to JS5.

Thank you Matt, I almost put that wording exactly in my question, but as I'm new to all of this, I didn't want to sound like a tool. Glad to know I'm getting a pretty good grasp on it just from reading. I am EXCITED about this project.

Thanks again!

Ok, I have purchased and I am assembling my board, and I have reached the point of installing the MAP sensor(s)(Step #53). I have run into a small problem (or maybe not a problem at all, just a matter of some creative thinking).... It's a MS-II v3.0.

Per the instructions here; http://www.megamanual.com/v22manual/3bar, to use an external MAP (mine is on my throttle body) I need to "connect a sensor output wire from Pin #1 of the MAP holes on the PCB to a free pin on the DB37 (use #25, which can be connected by running the sensor output wire you just installed to X11 on the PCB)."

Well, I will also be running an IAC stepper motor, and according to the wiring diagram here; http://www.megamanual.com/index, my IAC will occupy Pin #25. Also, this diagram indicates that Pins #20-37 will all be occupied since I will also be running ignition timing control. So it seems that I will not be able to connect my external MAP output to any of Pins #20-37.

I see that there are a number of free pins on the "top" side of the connector (#1-19). By the looks of the diagram, pins #1-19 are used for grounding(I don't have my board in front of me to confirm this, #8-11 and #18-19 are for sure). Is it possible to use one of those pins (#1, #3-7, or #12-17) to bring my external MAP sensor output into Pin #1 of the MAP holes on my PCB?

Or is there another, better solution?

Also, for the 5V signal going to my external map, do I understand the instructions correctly; that I just need to splice into the 5V power wire going to my TPS?

Thank You!

Pins 3-6 go to SPR 1-4 on the PCB

I believe I may have answered my own question relative to the output on my external MAP after looking at pictures of PCB's online. However, confirmation on the 5V power for my external MAP would be appreciated....

It looks as if there are at least (4) extra holes in the PCB near the DB37 labeled "SPR1-4" that are connected to Pins #3-6 on the DB37, AND are not used for anything else. I should be able to get my MAP output into the DB37 on one of those pins, and jumpered from the corresponding "SPR" labeled hole to the MAP hole #1, correct?

The "spare holes" will be under my PCB mounted MAP used for baro correction, but I ought to be able to put my jumper on the top side of the board, or even space the PCB mounted MAP away from the board.


EDIT________________________________

trakkies wrote:Pins 3-6 go to SPR 1-4 on the PCB

Looks like you beat me to it, thank you!

I stopped working last night before I realized I was going to run into this issue. Bored at work, I was plotting my next steps for tonight and ran into this. Would have been a simple solution with my board in front of me, but I wanted to make sure I had an answer when I got home tonight.