Rotax 912 ULS Tachometer problem

[romaja]

Just built a Rans S-20 Raven and have noticed on start up the RPM occasionally reads zero after start. It usually starts working several minutes later after the RPM is increased. It does not happen every time. I did a continuity test on both wires and they checked good. It doesnt act like a loose connection as once it starts working it continues to work until shut down.It is not erratic or spikes.

The blue/yellow wire from the engine goes to pin 32 on the EMS. The white/yellow goes to ground.
The manual talks about a Pul/rev tach calibration. Not sure if this would help or what to enter?


Thanks in advance.

 

[dynonsupport]

What engine?

 

[romaja]

What engine?

Rotax 912 ULS

 

[Dynon]

The pul/rev setting for the rotax is 1, which is the default. And if it were incorrect, your RPM would be wrong, but not zero. Once it reads, does it continue to read even when at low idle (where it presumably was zero previously?). Is this SkyView or an EMS/FlightDEK product? Do you have any resistors installed.

Because it seems to work a few minutes after start, I wonder if there is something about the engine or connections warming that is affecting things.

 

[romaja]

The pul/rev setting for the rotax is 1, which is the default. And if it were incorrect, your RPM would be wrong, but not zero. Once it reads, does it continue to read even when at low idle (where it presumably was zero previously?). Is this SkyView or an EMS/FlightDEK product? Do you have any resistors installed.

Because it seems to work a few minutes after start, I wonder if there is something about the engine or connections warming that is affecting things.

I checked the pul/rev is set at 1. I flew it today for an hour and RPM guage worked normally. I shut down for 20 minutes and started it back up and RPMs read zero. Shortly after takeoff at 700 AGL the rpm started working again. I spoke with Mike H. and he said hole 32 on the EMS is not providing the required volts of 10 volts and that I should move that pin to #34 or 35. The location of the harness isnt easy to get to behind the panel but if this my only option, I will try this.