RPM Fluctuations, ARINC Failures

[damonmeyer1968]

1) My Skyview RPM display fluctuates wildly between the normal RPM and some much higher seemingly random RPM readings, rarely under 1000 RPM, but more frequently at higher power settings until it's almost continuous at cruise speeds. This is in a COZY III pusher application, with one mag and one LightSpeed EI. What are possible causes and solutions, and next steps to troubleshoot?
2) My Garmin 430 GPS is hooked up to the Skyview via the ARINC 429 interface. It almost always works when I first power up and start flying around - that is to say, when GPS 1 is selected on the Skyview, I get course guidance on the Skyview's HSI. However, it regularly fails after a few minutes of operation. I get a warning that the ARINC 429 is offline, and the Garmin 430 displays a message about the ARINC 429 failure as well. Then no more guidance. What are possible causes and solutions, and next steps to troubleshoot?

Thanks,
Damon

 

[timfwalsh01]

Damon,

I have a Velocity with GNS-430.  My ARINC module went off line as well.  I flew for about 50 hours and then suddenly, module would not work.

After lots of trouble shooting, it was the Xpnder antenna that knocked the module off line.  I moved the antenna, now no more issues.  Tim

 

[dynonsupport]

) My Skyview RPM display fluctuates wildly between the normal RPM and some much higher seemingly random RPM readings, rarely under 1000 RPM, but more frequently at higher power settings until it's almost continuous at cruise speeds. This is in a COZY III pusher application, with one mag and one LightSpeed EI. What are possible causes and solutions, and next steps to troubleshoot?

Hi Damon,

Sorry about the issues. Could you let us know how you have your mag and LightSpeed EI connected to SkyView? What size resistor do you have in-line on the mag connection?

The first thing to check on the ARINC offline issues is Tim's suggestion about the proximity to the transponder or com antenna.

 

[damonmeyer1968]

I'm using the Dynon leads from mag and LS EI; I believe it's a 30 ohm resistor inline from the mag but will confirm.

I have a few (limited) options in my Cozy to get the ARINC further from the txpdr antenna. how far does it ideally need to be...is 2-3 feet enough?

I will say that I have flown the plane twice (total 1.4 hours) since my recent v10 upgrade, and no longer see the RPM fluctuations. Was there something in that upgrade that fixed something that could be related to RPM reading?