I have an 84 z28 and my speedo and the tach do not work. The tach is always at 1500 and the speedo is at zero. All other gauges are fine. Please help if you can. Thanks.

 

speedo is the cable got broken somewhere. more than likey in the transmission. unscrew it and check it out,.

 

On my '90 the Speedo and Tach are electrical, not mechanical.
If you have a cable running from tranny to back of Speedo your problem is likely in cable or one of the ends has come loose. If your electrical like me, there is a bad connection between gauge or gauge cluster and harness wiring connector. Carefully inspect both ends of the mating connection. There is likely a bent or oxidized connection or the connector is not seated properly. That's my $.02!

 

up to 90 they used a cable for the speedo. cable is either broken/unattached or there is an issue with the drive gears in the trans or speedo itself.

do any of the other gauges work? it could be the gauge itself or the wire is off/broken from the distributor

 

well i will not be out to the garage to test any of your suggestions till this weekend but i do know that all of the other gauges do work except the speedo and the tach. i will check it out and let you know whats up. thanks for the help

 

well i ended getting out to the garage and i followed a cable that went from the tranny to the speedo. It was unhooked at the speedo. I tried to hook it up without pulling the dash and gauges apart but couldent see to well up there. Does the cable just screw on?

 

it just pushes in like 1 of ur sensors.

 

it screws into the back of the speedo, or at least mine does. it will require pulling out the gauges and console to screw back in

 

doesnt screw. u have to might have to turn it a lil bit to align the squared part, but it just snaps in. u dont HAVE to remove the gauges but it does make it easier.

 

I ended up with problems involvng a few things this week so my schedule is packed. I will be working on the car later this week hopefully. I will look into all of the suggestions and tips everyone gave me and let you know on them. Thanks everyone for helpin out.