how many miles?
i searched civic and integra dead tach. i don’t come across pre 1990 data. read mostly1990-2000. many issues for dead tach unsolved - ur not alone. some replaced cluster, some worked, others not. some replaced igniter, some worked, others not. several problems seemed related to aftermarket distributors - proven by problem occurring after installation
a reasonable technique was to buy an aftermarket tach. connect a blue wire in dash an confirm it works. however, some reported aftermarket tach worked, oem didnt. one reported swapping a friends working cluster, and it didn’t work.
i’ve worked w a lot eclectronic halt and reliability testing and fal analysis. my hunch is to solder an auxiliary ground off the tach wires in the cluster and confirm a “true” ground. i’d also remove the pick up out of the dizzy, inspect those wires. review w jewelers glass. i’ve never looked at it. so if there r solder joints, reflow them. im going this direction bc people reported aftermarket tach work, oem does not, implying oem tach might need a cleaner, stronger signal?
another reported a new ignition coil solved it. maybe this put the power to dizzy back to spec?
look into that water pump for over heating. that old lady may had it replaced by a shop using aftermarket parts. i believe asian made honda oem pumps.
Keepin' it OEM