I am trying to wire up the stock tach after i removed the ecu and put in a holley efi system in.
I found a diagram that showed that the tach signal was from the negative side of coil. But the diagram looks like there might be a resistor in there somewhere. If so where is it or can i put one in line?
https://goo.gl/images/bhYm1e
I tried a jumper wire from coil and it made tach jump just a hair on startup and nothing after it started.
Interesting enough i tried another jumper from tach out on msd box and it seems to work. But i didnt try it long afraid of overloading something.
Tach signal is supposed to be dc square wave but i dont know voltage. The msd box puts out a 12v square wave. So im guessing it would be ok?
I found a diagram that showed that the tach signal was from the negative side of coil. But the diagram looks like there might be a resistor in there somewhere. If so where is it or can i put one in line?
https://goo.gl/images/bhYm1e
I tried a jumper wire from coil and it made tach jump just a hair on startup and nothing after it started.
Interesting enough i tried another jumper from tach out on msd box and it seems to work. But i didnt try it long afraid of overloading something.
Tach signal is supposed to be dc square wave but i dont know voltage. The msd box puts out a 12v square wave. So im guessing it would be ok?