Howdy, im attempting to wire a tach into my 93 ranger. its the 8 plug 2.3 with all the coil pack things on it. now the tach has 4 wires, red, black, green and white. i know the white one is for the light in it, blacks my ground, but not sure what that green one does or where to hook up my red. each set of packs has 3 wires going to them and i tried hooking it in to all 6 wires, at seperate times, and it works while im at idle but as soon as i give it gas the tach just drops. take my foot off the gas and it will jump to the rpm i was at and fall with it and it seems accurate, but why does it do this?
Red is switched power for the tach, and green is signal pickup. You should consult the manufacturer about hooking it up, since it sounds like you don't have any instructions with it. Many tachs need an adapter to run on a distributorless engine.
The DIS module on the intake manifold has like 6 wires coming out of the bottom of the module and the far right wire, which is black with yellow strip or yellow with brown is the signal wire for the tack. You need to splice the green wire from the tach to this wire, and then hook up the red to a postive when key is on, and black to a ground, and then the white is for the light which goes off the headlights.