I got a 90 Civic about a year ago after it set for the better part of 5 years. Only had 90k original miles and I wanted to use it as a commuter for work. As expected, it has a ton of issues. I’ve replaced almost everything.
tach isn’t working now. I recently replaced plugs, wires, distributor. Any ideas why tach would be out?

 

What is "almost everything"?

The distributor provides the signal for the tach. When did the tach stop working?

 

That’s not bad. Replaced everything and just the tach won’t work? If it commutes fine to work and back. just leave it

 

I would just have replaced the cap, rotor and o-ring on your old distributor and would be fine if your tach was working before with it compared to your "new" one. Swap those parts off your new one to your old and your tach will come back to life possibly lol. Some new distributors can be junk if they are cheap ones.