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

I'm trying to use the Tach signal wire on my 97 GSXR to control a fuel only MS. The weird thing is the ignitor box shows 12v on the tach wire at 0rpm and seems to bring it low to pulse the tach. The thing is, it never seems to drop all the way to 0v and the MS won't pick it up. While cranking the voltmeter shows about 2.5 to 4 volts. Is there any way to get this to work?

Triggering from the coils is a no go, the primary side of the coils run at 200v. Unless theres something I havent heard of that allows this to work.

MS1 3.0 stock code

Weird signal, but I've seen them before. You could build an op amp comparator circuit that sends out 12 volts whenever the signal drops below 6 volts or so. Or take a 5 volt zener diode and put it inline with the tach signal, banded end away from the MS.

The zener diode trick sounds promising. Ill give it a try tonight or tomorrow.

Thanks