1980 razz

i know its been disscused before but here i go..when i start the vette up the tac jumps a little bit..thats all it has ever done since i got it..where do i start to fix this problem..how hard is this project from 1 to 10..any help apriecaited..thanx all

74Vetteski

I could be as simple as replacing the plastic gear mounted on the side of the trany where the tach cable is mounted to trany. The gear is made of plstic and can have a tooth or more worned down. This happened to me. Simple repair. If it is your cable that is screwed up, its a tougher job, likewise if it's your tach gauge. Best bet is to start with an $8 plastic gear mounted to the side of your trany.
Peter

Frankenvette

On my 80 it was just bad connection on the tach board behind the tach. I cleaned all the connections with 220 grit sandpaper and electrical cleaner. One person just posted that it was a bad tach filter. They removed the tach filter and the tach works. Also check your connection from tach to the distributor for a good clean connection. Start from the most simple fix working towards the more difficult. Usually it turns out to be the more simple fix. I would suggest checking electrical connections first. Remember how old your wiring is.

Regards,

Jim

Wrecked82

I was the one with the bad tach filter. I first thought it was a bad board, which I replaced to the tune of $75. Did not fix it. Thought I might need a new tach, as the 82 is electronic, not gear driven (what is the 80?). Then I just decided to disconnect the connector after the filter and run a jump from there to the test connector at the tach. Voila! Tach suddenly works. So I have just cut out the tach filter and soldered and shrink wrapped the ends. Had to reset the tach needle, as it read low. This is real easy. Pull off needle, turn on ignition, not starting car, re-attach needle at zero. No effects to date from no filter. No radio noise, no needle jumping, no anything. So, I would try jumping aroung the tach filter first (with a wire, not you jumping! :rolleyes: )

1980 razz

where excactly is the tach filter located? is this posible to check without taking apart my dash?i checked the connection to the dist and it seems fine?

bence13_33

Check your tach filter. It is bolted to your intake manifold. If it is not bolted down it can make your tach do strange things. I would check that first and then go from there.