My tach stopped working, is this it?

[Jinnai]

My tachometer stopped working a couple days ago, as I was driving along it was jumping between 0 and whatever it was doing at the time and eventually settled at 0. I poked around in the engine bay and found this cable loose:
https://i.imgur.com/zLPAajV.jpg
Is that the tach cable? If so, how do I get it to be attached again?

[Havoc_Wolfy]

that is your speedometer cable. it connects down into your speed sensor on the top rear of your transmission. there should be a little locking clip under that rubber boot. carefully work the boot up to take the pin out (careful to not lose it) insert the cable into the top of the sensor and give it a few twists back and forth to make sure that the keyed part slips in where it needs to go. then take the clip and slip it around the tip of the cable through the horizontal slot in the sensor. you may have to work at it to make sure it actually snaps in. once you think you have it, gently tug the cable to make sure it is locked in. then carefully slip the rubber boot back down over the clip and you should be all set.

As for your tach issue, i believe that its electronically calculated via the distributor. since the car runs, the distributor is correctly reading the rpms. what i would do is go ahead and take a look at your gauge cluster and the wire harness it is connected to. i had some speedo issues and discovered the harness to be bad. for the longest time i was able to just smack the cluster to get a connection again.

let me know what you find

[ShiRen]

Check the connections on the dizzy and ignition coil