Quick question for the 4 channel ignition/injection board
 

I am a little confuse on what to do with ground. it says it usually comes from the ms board (which i have hooked up). Do i need to worry about what it says about using an external ground?


You will also need to provide ground which also usually comes from the MegaSquirt board. You can use an external ground by soldering a jumper between the ground pad and the unidentified pad just to the right; this will connect the drivers ground to the DB15 ground pins.