I recently purchased a 1981 Z28 running project. One issue I've found is the speedometer and tach are not working. Is this a common problem? Is it a difficult repair?

Does the tach and speedometer work in conjunction with the original on board computer? My fear is, since the car has a newer crate motor exchange, the computer may have been deleted.

 

uhm ok dont quote me to the fullest because i dont know anything about the 81s computers k

as far as mine works. theres a plugin in the back of the whole cluster unit. check that out. check out your distributer and make sure the wire connected to tac. is connected to tac haha. thats a good start. on the tac.

the speedometer as far as i know as i said dono know 81s but i doubt its a ton different than my 79. it is a the spring steel cable driven speedometer if THAT isnt working take the cluster out spin the drive on it and see if you can at least hit 20mph with that and check to see that the drive gears inside aren't toast. if that is fine. check and see if the spring cable drive has been worn though. you can get replacements at most auto shops. you just run it though with alot of dry lube (graphite powder) and check the length into the transmission gear so your going to have to get under it unscrew the lock to the drive gear check make sure your not binding up the gear much. hope that helped

 

The two are unrelated, cable driven speedo and electric tach. Whoever did the swap may not have connected everything back up again. Also check to see if your car has cruise control. The speedo cable is split in and out of the cruise module, and sometimes the internal connection breaks.