Tach troubleshooting

[JulianoMaiaLopes]

I would like some information to solve a problen that I have with FlightDek D180 installation.
My engine is a Rotax 912S, and I decide use the Rotax Tachometer as a back up indicator.
But this indicator doesn't run correctly and FlightDEK D180 (rpm) run correctly.
Rotax tach rise indicated RPM after 3200 RPM
I receive some instructions to adding a 100 ohms resistor to the trigger coil. After I put the resistor, Rotax tach run correctly, but the FlightDek D180 doesn't. FlightDek D180 indicated 0 RPM
I routed wire separately from wire bundle and away from ignition leads. I ground the tach and shielding wire separately.
I would like help if someone know how to solve this problen.
Thanks,
Juliano

 

[dynonsupport]

As an experiment, try disconnecting both the rotax tach and the resistor. In other words, connect the trigger coil exclusively to the Dynon. Does that change anything?

 

[JulianoMaiaLopes]

I did and D180 work correctly. But I haven´t the back up tach as a would like.

Thanks.

 

[dynonsupport]

OK. This may mean that the other tach gauge is affecting the the signal in some way which is damping it in some ways such that the EMS isn't able to see the tach signal when it's hooked up.

As a next step when hooking back - make sure that the 100 ohm resistor is not inline with the EMS connection. I'm wondering if you need it at all. Our EMS pickup doesn't, though we can't speak for whether that other tach gauge does or not. You might be able to just split the tach wire, without any resistor inline.