2007 G1000 Ovation w/Dual Tachs, E.I. Tach Gone Wonky!

[Jeff_S]

Hey all. I've got one of the early G1000 Ovations that has the extra E.I. tachometer in the lower left portion of the panel. I've heard that this was required during early certification as the G1000 tach wasn't certified yet and this was the "official" tach.  Don't know if that's true or not. At any rate, lately that E.I. tach has gone wonky on me, showing very radical readings both higher and lower than what the G1000 is showing, although usually within 10 minutes of flight it settles down.  I suspect corrosion, which here in Florida seems to be my #1 culprit whenever I suspect electronic weirdness.  So now my question: are there individual pickups for each tach in the system, or is there one pickup that is then split somewhere to feed both the E.I. and the G1000?  In either case, where would I look for corrosion in the connection to the E.I.?

Appreciate your thoughts...thanks!

Jeff

[buddy]

If your G1000 now shows 2700 RPM as a red line on its tachometer then I don’t think you need the E.I. tachometer any more. I removed mine after a software update years ago.

[Schllc]

Yep, merely requires the software update to eliminate the extra tach. 

[Jeff_S]

Okay, my G1000 tach definitely shows the correct redline so that makes the E.I. redundant, which I suspected anyway.  I may just remove it as well.  Thanks!

[skykrawler]

On 8/29/2025 at 6:50 AM, Jeff_S said:

Okay, my G1000 tach definitely shows the correct redline so that makes the E.I. redundant, which I suspected anyway.  I may just remove it as well.  Thanks!

I know somebody who might buy that for a reasonable price.   A Bravo owner with a tango uniform transducer. PM me.

[Jeff_S]

To follow up on this, I had the avionics shop clean up all the contacts to see if corrosion could be the culprit...it often is here by the Atlantic coast. But in this case, no such luck...the unit appears to be Tango Uniform.  I talked to EI and they said they had a core exchange program where they would charge half-price for a new unit. That makes a new unit $350 ($700 x 1/2).  I'm still deciding what I want to do.  In the meantime I just have it marked INOP.