Golf mk2 rev counter not working (MS3X, Vagtronics adapter)

[clust]

I have MS3 3.57 + MS3X installed on my Golf mk2. In general everything else is working fine except rev counter. On my first setup I tried to connect MS3X tach output PIN26 to rev counter wire on stock cluster (red/black wire on VW CE1) and set RPM output to Normal on Tunerstudio. With that setup rev counter doesn't work at all. Then I connected Vagtronics rpm adapter (http://www.ebay.com/itm/Vw-golf-Mk2-AGU ... 2088588070) which should work at least with stock Motronic ECU and stock mk2 cluster. RPM counter works now but the problem is that it reads about 3000 rpm at idle (truly about 850 rpm). Do I have to put some transistor or resistor between tach signal wire to get correct rev counter reading?