tach wire on 96 volkswagen jetta

im having a lil trouble with my disk drive, but worse case- go to your injectors and test them with a multimeter. usually theres one wire that has a different color, and usually thats the one. If u cant find it this way just test each one. ground ur dmm and stick the red in the injector and start the car. while moving the throttle cable or having someone give the car normal gas your meter (set on ac) should fluctuate back and fourth as the gas comes and goes. normally it shouldnt go higher than 3.5-4.1 at the most. if it does look for another that stays around the 3.5 range. If u cant find another than use what ya got. tap into it solder, tape, and loom it. hope this was some help. by the way, heres the diagram. just got my computer working. peace