Tach & Steering issue
 

I recently aquired a 1988 RX7 and I have a few issues I hope someone can help me with. There was a fuse missing and after replacing it, the power steering got more responsive, but the car now beeps when it is in motion and stops beeping as soon as the car stops moving. The tachometer doesn't work, with or without the fuse. In the schematic wiring diagram, both the tach and power steering control unit get their signal from the ignition coil so I'm thinking that the two are related. I have searched for a disconnected or broken wire to no avail. Has anyone else had this problem? If so, what was the solution?

Definitely related. The 4 pin connector at the trailing coil is the first thing to check. Make absolutely sure it is not broken, loose or gummed up. The yellow/blue wire is the tach signal. If the connector is good, then you may need to replace the trailing coil.