t2ku is totally correct. 88-89 is totally different wiring than 90-91 and even totally different looking.

I think a crx will work on a sedan. depending on the year sedan I might have one lying around the garage. I parted out a 88 civic with a tach and also a 89 sedan with a tach.

let me know the year and I might have one.

Now the only issue might be dealing with the dizzy. It might not have the tach feedback wiring.

If your speedo is not working also check down at the tranny to make sure the cable is connected. A quick test is hook the cable from the tranny up to a drill motor and see if the speedo works. If the speedo does not work it is the cable.