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G3X Tach zeroes out on one mag

msaltzman14

Active Member
Hey All-

Has anyone had this problem?

I have a brand new G3x touch system. I have one p-mag and one normal mag. On run-up, when I turn it to the p-mag, the tach goes to zero (although engine is just as strong audibly), on the normal mag it shows the tach correctly, just about 60 less than I started at.

When i go back to both the tach works normally again.

Any ideas?
 
Some systems are only hooked to one or the other. Sounds like yours is only hooked to the magneto, which must be picking up the pulse from the P-Lead. Some use a magnetic pickup screwed into the housing which will show RPM even when the the magneto is grounded. If using the P-Lead, the signal is grounded (not there) when the mag is grounded.

See if your P-Mag has a wire running from pin 6 (tach) into the cabin.

My Dynon SV is hooked to both but on different inputs due to the different signals (mag vs P-Mag). Whichever it picks up first is the one it will use. If one goes offline (e.g. during mag chk), it switches to the other.
 
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