So as not to thread jack another thread.
In post #14 of this thread
It talks about current driven tach in the 240Z and voltage driven tach in the 260Z and up. Does current mean the amps increase as the revs increase and likewise voltage means voltage increases with revs?
I have a tach issue where my tach works fine from idle to about 3000 revs and then pretty much stays close to 3000 for all higher revs. I have a ZX electronic dizzy and the balast resistor has been removed (I didn't personally do this, but an old school Z guy that I trust did it for me). All was well for about 3 years (probably no more than 4000 miles). Then one day about 5 years ago the tach just slowly crept all the way up on its own unrelated to actual engine revs. I pulled over, shut the car off, started it back up and it's been in the idle to 3000 okay mode since. The car runs just great, just not the tach. It's not a big deal, it just bugs me. I've cleaned all the connections with no change in symptom. Looking for any suggestions... Thanks