Hey guys and gals, I am having an issue with my tach in my 84 Z28 H.O. car. Every time I start the car the needle spins all the up and just sits there until I shut the car off and go to start it again, then it spins right back up and sits. I have been thinking the tach itself is bad or the resistor is bad. Any suggestions on how to test or find out what it could be? I have had the same issue with 2 distributors, the stock and a vacuum advance distributor I installed when I swapped in my 350.

 

Sounds like a wiring or internal tach issue to me. Double check all of your grounds under the dash and make sure your tach wire coming from the distributor isn't chaffed and grounding itself to metal somewhere.

 

https://www.thirdgen.org/forums/elec...meter-fix.html this works on all third gens.