Erratic jumping tachometer. See video.

[glenadavis]

I have a 2013 RV-12. Recently, at cruise, say 5400 RPM, the tachometer in the Dynon Skyview would momentarily jump to 5640, only for a millisecond, then return to 5400. This would continue to happen approximately every seven or eight seconds. Anyone have an idea what may be causing this? . Thanks.

 

[D-Dubya]

Check for a loose connection first, anywhere from the probe to the instrument input. I don't see a video, so I can't tell if the engine is actually revving up or not.

 

[Quotafiller]

Loose ground is generally the culprit

 

[lr172]

generally speaking, consistent rhythmic problems are not wiring issues. things like bad crimps and poor grd connections tend to have highly irregular intermittency. if it does it every 7 seconds, like a drum beat, i just can't see that as a poor connection.