Gidday, this is my first, so go easy on me!

I'm trying to get an aftermarket tacho to work in my EFI distributorless 1.5. I have found tacho power, earth & instrument backlight tap-inable points on the centre plug on the back of the instrument cluster - there are 3 wires in a row next to each other: black(earth), white(backlight), and blue/black(tacho power).
The circuit diagram in the manual also shows a white wire coming into the tacho. This wire is not present on the centre plug of the instrument cluster!

My problem is: do I have to find a (one & only one of them I hope!) white wire coming straight out of the E.C.U. main plug & tap into that, or as I was juist reading do I need an isolator circuit of some sort? I'm just a bit nervous (sorry-VERY nervous) about this & I want to be sure so I dont destroy the E.C.U. So at the moment I have a tacho that lights up nicely even though it says I'm doing no revs when I actually am! I would appreciate anyone's help on this, & I hope to be able to help someone else in the future on this forum if I can

Hi nev,

Din't know if your still looking for an answer, but have a look here:

http://www.hyperaustralia.com/forums/viewt...f=11&t=2545

Thanks for the help Hendryc on tacho installation, I have since verified the info & installed the silly tacho & all is fine! Turns out I was right - The white wire (& the only white wire thank God!) coming out of the E.C.U. is where you connect the signal wire for tacho drive. I ended up firstly disconnecting the main battery + terminal, then unplugging the E.C.U. for better access to the plug wiring. Not wanting to compromise the reliability of ECU wiring, I carefully stripped back about 5mm of insulation off the white wire WITHOUT CUTTING IT!, & about 15mm off the END of the tacho signal wire. Then I wrapped the tacho wire around the exposed 5mm carefully & laid it parallel with ECU wiring. I then wrapped nice & neatly a 20mm piece of electrical tape evenly around the connection, followed by a cable tie (zip lock?) around the centre of the connection. This non-solder connection method keeps the flexibility of the wiring, without cutting existing wiring, & I pretty much guarantee this method to last FOREVER! unless used underwater. Incidently I use the same connection method with car stereo wiring as well & I have never had a failure!