i've done everything possible, even taken it to an auto electrician, to get a tacho signal out of the ECU and no go. have hunted through wiring diagrams off the net to the point of madness to find the right wire (the one you talk about is the correct wire and yes it does not put out a signal - the sparky confirmed this for me).
engine runs fine, has been for around 3yrs, but no tacho signal coming out of ECU.
the timing loop wire at the back of the engine was one possibility i tried, but as stated it did not put out an accurate reading - i revved the engine to what i thought was 4-5,000rpm, but it only got to around the 1000rpm mark.
hence why i am asking what oldschoolers use when they wire in a tacho into a car with no tacho, not how do i get a signal out of the ECU.