GRT Avionics

Hello,
I have a GRT modified EIS4000 to work with 24 V system. Unfortunately the display reads only 20-21 V and with teh engine running max. 24 V.

So this is at least 3-4 V to low. My GARMIN 430 reads proper 23 V and with engine running 28 V.

Any sugggestion what can be the problem ?

Thanks ...

Hello,
I have a O360 with one electronic ignitino (LSE PLASMA II+) and one magneto (Slick). Due to the fact that I am preparing for first Permit to Fly and corresponding tests, I am not sure whrther it worked before or not...
So my problem is, that I wired the LSE to Tach input I and the Mag to ...