Hi. I had fitted a Astra get Digi dash to my Orion a year back and the rev counter has always been working but on a low reading ie approx 4000 revs shows about 2000

Anyway I bought a universal rev counter pod type and wired it up to green wire hoping this would be accurate but it's the same as the Digi dash one

My question is could I run a new feed for the rev counter ie from alternator etc as I think the green wire currently goes to the edis module for pickup but maybe this isn't a clean enough signal for non efi rev counters