to start i replaced the alternator because i would lose voltage when the headlights were on and now that problem is fixed. but now in order for my rover to charge properly and the tach to work i have to rev it to about 3k rpm then the tach works fine and the voltage is also fine, i had to do this before i changed the alternator as well. now my question is what the hell could be causing this? any ideas would be great, and an alternator wiring diagram for an '89 rrc with a 3.9l would be helpful. i just replaced the wiring as it was but i think someone had fiddled around with it before i got it, so that could be part of the problem as well.