Testing tachometer

[peastham]

Hi, I have wired my EMS to the lightspeed electronic ignition to tap into it's tachometer output (pin 6). When turning the prop by hand, I can get it to generate a few sparks, but the EMS tach does not budge.

Does the EMS expect to see more than a few RPM before showing any value?

Possibly related: the Lightspeed has a "tach ground" output (or is it an input?) but there is no corresponding input on the EMS. I wonder if this needs to be grounded...

Thanks - Paul

 

[dynonsupport]

Paul,
Yes, the EMS has a threshold before it will read any RPM. It needs to see pulses that are pretty close to one another and even before it will read any RPM.