Hall/Optic circuit or coil negative input

[bigdawg]

I am up to step 50 on my MSII build and I am using the MSD 6AL input circuit for my ignition on my turbocharged mustang, well according to the assembly instructions, it says to use the Hall/Optical input circuit, which I wired in the resisitors, and left out C30, I did not solder in D1 and I also left out D2 as stated by the note. I also installed U3 and I left the C12 location empty. So now I am ready to set up my MSD and it is ready to go...correct?

OK, now do I need to install the section where it says For triggering off the coil negative terminal/points ,

Is there a reason that this needs to be done, or do we install both and then move on to step 51 of the variable reluctor (VR)???

Basically my question is do we install both ignition inputs or just pick one based on your choice of ingnition inputs such as mine, which is the MSD 6AL?

I ask because I seen this message for step 51
51. As we noted in step 50, there are two input circuits for the tach signal. One takes the square wave input from a hall sensor, optical sensor, or points."In most cases, you should install both circuits, and make the selection between them with jumpers." However, if you do not want to install the variable reluctor (VR) circuit as well as the Hall circuit, skip ahead to step #52.

It says to install both circuits, but I can guarantee I will never go without my MSD 6AL, so is there any point in me installing both igintion inputs?

So another question is if I only install the Hall/Optical input circuit then I install the VR circuit to proceed?

[bigdawg]

I got the answer form Jerry at DIYautotune.com so I got it figured out, but I am copying and pasting the emal here and it will be held in case anyone else might need the advice on a search feature. Thanks again Jerry.


The MSD 6 doesn’t actually get involved at all on the ignition input side of things into the MS—just on the output.



Input: You want to do the Hall/Opto input circuit and then do the TFI Input mod. You can install the VR components if you want to but they aren’t needed, and when you jumper then board for Hall/Opto input they won’t be used. I’d personally still install them to make the box more flexible in case it’s ever used on another car down the road or sold…

http://www.megasquirt.info/ms2/TFI.htm Just the input mod… not the TFI output since you’re using the MSD box… see below-





Output: You want to do the MSD Output mod http://www.megasquirt.info/ms2/msd6a.htm





Then the output from the MS (pin36) drives the points input on the MSD6 box and it will fire the coil…









Thanks,



Jerry Hoffmann

DIYAutoTune.com

[Redrocket]

So, for an MSII with MSD 6A and TFI you:

do the TFI input mod, D1 is jumpered and D2 has a 1k resistor instead of the diode
don't do the IGBT pullup mod that it states in step 65 for the ouput?

my jumper settings are as follows

tachselect toOPTOIN
IGBTIN toJS10
IGN to IGBTOUT
OPTOOUT to TSEL
XGI to XG2

sometimes this stuff can be VERY confusing!