Digital Tach issue

[J0nathan225]

So tach is showing an issue with the rpm reading... left mag? This is all while engine noise stays the same and run-up check passes with no issues (rpm and EGTs).

Mags are sub 150hrs old, but it's hard to tell, to me, the condition of wires, but they are all firmly attached. 

I think connection issue to the p1000 tach, p-lead or orgnition switch short issue thoughts?

 

Please ignore the +35 PSI fuel pressure, it's being addressed... it's accurate with some quick -35 math

[carusoam]

What are the various blinking lights indicating?

Expect the electronic tach is simply a counter and display, receiving a signal from a mag firing... find where the sensor is, clean, and chase it back to the tach...

use a phone app to determine the actual engine rpm in case you are unsure what the tach is telling you...

PP thoughts only, not a mechanic...

Best regards,

-a-

[J0nathan225]

Oops should have included that, yellow flashing indicates rpm mis match between left and right mag, red light indicates which mag is having a interrupted signal. Manual mentions "floating points" or mag failure as other possible causes, but with the engine having no signs of an issue that leads me to believe, and HOPE, it's just a bad connection somewhere. 

I looked at the mag side of things, looked fine, I guess today I'll take a look at the back of the p1000 gauge. 

[mooniac15u]

Your placard doesn't seem to match your tachometer markings.

[J0nathan225]

Hmm well the placard to the right matches the p1000 which is the limits for my 3 blade. Dropping off at cole aviation hopefully they can take a look, sadly I don't have the time to make it to @AGL Aviation.  10 mins into the flight I conducted a lean in flight mag check, it passed and the fluctuations stopped until I landed. Odd! 

[Nikolai]

I have similar intermittent issue: occasionally digital Tach shows left magneto fail (red light) and placing key on "L" -results in tach reading 0. Engine is working smooth with no anomalies. After shut down and re-start the engine the problem seems to disappear and everything looking good. Maintenance team cannot replicate the problem, because it happen only once in a while. Any ideas what can be wrong?  Thank you.

This is "BOTH"

and this is "L"

[carusoam]

Welcome aboard Nikolai!

Is that a video or some pics?

If a video... drop into YouTube... and copy link here...

If a pic... find the paper clip icon and follow the instructions...

Best regards,

-a-

[Nikolai]

these are the pictures of tach with ignition key on "BOTH" (one red  light ON), and ignition key on "L" (both red lights ON).  Engine is running...

[carusoam]

What engine is that attached to?

I have seen a few mag pick-ups not work very well.... a very expensive sensor, unique to some nice looking Mooney panels...

The Horizon tach is a common replacement device used on some 310hp Mooneys, and doesn’t have many complaints...

Might want to look up what sensor you have it attached to... then search to see if there are any known issues...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Nikolai]

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