An update - today replaced the FD with a used one,new O2 sensor .
The car started right up and was running well... but after warmed up I noticed that the EHA is leaking but not from the "o"rings and the rpms went gradually down.I turned it off.
Now I am waiting on another EHA and Jetronic fuel pressure test kit.
I still can not find the culprit why the tach is not working.I put an extra ground but no results.Any suggestions?