After the info from yesterdays replies i spent a while tinkering in the garage when i finished work. Drilled through the edis connector to get to pin 2 on the edis, managed to get a wire from there to the rev counter then fired up the engine. It seems to be reading a little low compared to the readout on the megajolt software on the laptop.
So next i tried connecting to the signal wires going to the coilpack, i wired in a couple of diodes and then tried this which seems a little better. Its quite hard to tell if its reading properly though because i cant rev it too much as its only got a manifold on and is ridiculously loud even at tickover
Just waiting for a 60mm stainless bend coming then i can get my silencer on and try revving it a bit more to find out for sure. At least its actually reading something now though, so its a step in the right direction. I was only using donor instruments for speedo accuracy at iva and ease of fitment, turns out the time ive spent mucking about with a new fuel sender and now the rev counter it would have been just as easy to go with all new clocks
