i have a auto meter, monster tach, my shift light is set to go at 8000 rpm's it gets to about 7500 and all the sudden it freaks out and jumps up and down it is wired into my msd ignition so its not like it is wired in wrong does anyone have any suggestions.

 

it might be getting a funky cross signal from something else. Also ive seen distrubtors go bad and the tach will go haywire like that...

 

you can try replacing your igniter, thats what usually makes the tacks go crazy towards high rpm.

 

my tach was doing this because of a distributor problem. I think the main bearing had gone dry. Lots of brown dust in the distributor cap. I tried swapping in a different ignitor but that didn't solve the problem for me. I had to get the distributor rebuilt before the bad tach reading was gone. I assume at this point the bearing was seizing, but a bad ignitor or bad wiring could cause your jumpy tach. If you pull the cap off your rotor and see lots of brown dust, means your main bearing is dry and it's the likely source of your woes.


[Modified by Maxi, 9:26 AM 9/15/2002]

 

I had the same problem. I just replaced to distro.

 

Had the same problem in my GS-R. Ignitor was replaced (under warranty.. yay!) and the problem went away.