EMS signals go wrong

[Hotscam]

On our new 12 some measurements go wrong at irregular intervals.
Everything was fine during the first 60 hours.
After this the fuel pressure started floating between 2.0 and 5.0 psi and alarmed very often.
I replaced the Kavlico and cleaned the fuel system as there have been some problems with these as per Dynon notes, but this did not improve things.
Lately the fuel flow reading suddenly triples and starts alarming always simultanenous with oil pressure dropping below alarm levels. Oil pressure allo sometimes crossed out red, which would indicate wiring problems.
Pretty squary situation when you fly in the mountains at 7000 ft.
In the meantime I found there is nothing wrong with all these measurement values and the old Rotax keeps on going very well.
Everything may be normal for an hour and suddenly alarms start popping up.
On the ground all is always fine so very hard for fault finding.

Is feels like an intermittend wiring or grounding problem, but I cannot see anything common between the flow sensor and the oil pressure apart from 12v aux supply.
I cannot see the number of flow pulses increase so easily

What puzzled me during checking the Autocad wiring drawings from VAN's that none of the ground pins of the EMS220 are connected. How are these grounds coming in?

The grounds of the problematic sensors go into the wonder box and are interconnected via the pcb but do jot feed back to the EMS
The only ground to the EMS seems to be the bus ground but that cannot be the the correct way to me.

Anybody experienced this before or any hints how to attack this ?

Our other 12 with identical Skyview and software works perfect for 500 hours

[Bill_H]

Other people have reported similar problems. Consider this additional engine ground wire, which has also been said to solve them. http://www.vansairforce.com/communit...&postcount=240