I am in the process of installing a D15A3 head (from '87 Si) in place of a D15A2 (carbureted engine) head. Induction is dual side-draft Weber carbs so there is no ECU involved so the cam position sensor and other signals from the new distributor are not used. The distributors for each are different, as are the cams, so the original distributor from the D15A2 head will not work on this D15A3. I am attempting to use the D15A3 distributor in place of the original D15A2 distributor. Both distributors have 3 wires between them and the coil/ground, black/yellow, blue and green, These 3 wires from the new, D15A3 distributor were connected to the 3 wires which used to be connected to the running D15A2 distributor. My problem is that I can not get a spark with the new D15A3 distributor. What could be the problem?