So Am having a slight issue with my winter upgrades.
The engine is a 1.8 zetec blacktop running on a ford ESC ecu wired up with a Premier loom which says to use a green/red wire of the ecu to connect to the light green of the tacho/premier loom. It is all connected up but the tacho isn't moving at all. I have heard that diodes might be needed to resolve this but I can't find a definitive answer, anyone else had to resolve this issue and could give me some advice?

Jason

The esc tacho output is a 12v square wave, the durite tacho is looking for the back emf spike from a coil operation, the 12v square wave is not the right waveform to trigger this.

The linked diagram gives a schematic to emulate this output using the esc tacho output, only the coil part of the relay is needed, the internal diode/resistor and contacts need to be removed.



Another approach is to use diodes as per the following diagram, this will definitely work but needs to be added into your loom.


tachometer diodes


Dave

Hi Dave, your reply is awesome !!! Many many thanks, your reply has also been responded as by someone else so it sounds perfect.
Thanks again

Jason