Griff Taco drive

[steve-V8s]

Any idea what signal the standard tacho is expecting to see ? As standard I think it runs off the -ve side of the coil so probably sees fairly short duration fairly high voltage spikes. I would guess al least 2-300v peaks. The Emerald does a nice clean square wave which the tacho doesn’t like at all. Need to make up a bit of circuit to turn the 12v into something else but as I don’t have the original coil arrangement I can’t have a scope on it to see what the signal is. I know some people simply use a relay coil somehow.



Any clues anybody ?

[AntonyJ]

Emerald sell a tacho driver unit to connect the gauge to the ECU.

[steve-V8s]

if you have one of these driver units please could you tell me if it is passive or active. In other words does it have a +ve supply wire or does it just use the Emerald drive, ground and an output ?

[AntonyJ]

Four wires on it, +ve feed,-ve ground,input from Emerald and output to the tacho.
Nice neat little unit.