When sparking still need tach?

coyoteboy · Post by **coyoteboy** » Fri Jul 21, 2006 3:55 am

Do we still need the tach in signal if we are using (in my case) dual VRs for a toyota dizzy? I mean it seems a little silly to drigger the spark then use the tach signal to fuel - why not just fuel and spark at teh same time freeing up an input?

Post by **jsmcortina** » Fri Jul 21, 2006 4:23 am

When running spark and fuel your VR or whatever inputs ARE the tach input to Megasquirt and the coil is driven. The coil is not used as a tach source (because the Megasquirt is controlling it.)

The diagrams are already laid out in this manner.

James

coyoteboy · Post by **coyoteboy** » Fri Jul 21, 2006 6:14 am

Good good, thats what i was getting at in a round-about way lol. So i can lose my stupid noisy tach signal - good, thanks for that! I've not checked over the diagrams specifically for it - i'll dig them out again and re-read before i connect in my dual LM1815s.

Thanks