Ok 89 RS dont know if that maters at all but just went to the good ole junk yard and got a few parts for the baby!! but the problem that i am having is that the tach that i got is doing the same thing as the old one i know that it is working because the oil presure gauge on the tach is working but what the tach does is when i start up the car the tach is either pushed all the way down to the right ot if i move it with my finger about half way the needle the jups right over to the other side! so since i know that the gauge is functioning with the oil presure and the other tach did the same thing i really did not have to buy one from the yard but i thought a replacement might do the trick but aperently not so help me out you all what is the next step from here to get that bad boy working?! what should i check next i dont know where the car reads the RPM's at so if you can tell me all the posibilities that would be GREAT!!

Thanks!

 

I have almost the same problem, only mine always reads about 2000 to 2500 rpm too high. I tried replacing the tach too and it did not help. The tach signal comes from the distributor (The brown wire, I think)

 

yeah mine sometimes if it is fliped all the way to 70x100 and like i let off the gas or some combo of the gas and clutch it will start to fall back a bit but then sure enough if i start to go them BAM! it goes back all the way to red line and stays there so i really dont know!