i decided to post it here because this is where all the tbi guys are. i have a 1990 lo3 and i just got the msd digital 6 plus. hooked it all up with the wireing harness and it runs and everything, but my factory tach doesnt work. this is not cool at all. does anyone know what wires i need to splice to get it going again? keep in mind i am using the wireing harness so i havent had to splice any wires so far. just took the 2 connectors off the ignition module, plugged those into the harness, then plugged only ONE connector off the harness back into the module (doesnt make a whole lot of sence to me)

 

The yellow wire on the coil pluggin is the tach wire...is that hooked up anywhere?