i have an 88 GTA with an all digital dash i just bought the car and as i was driving it home the speedometer read 0, any ideas what causes that and how i can fix it?

 

Thats how fast your car really is!!!

(J/K)

What you wanna do is check to see which wire goes from the sender to the speedo. Than make sure to check the contact from your dash to the wire. (There should be two connectors that go into the back of the dash).
Than if everything checksout good check the sender.

It should be one of the two. Either the wiring is bad, or the sender took a dump.

Good luck.

 

Just a thought, check your ECM, or the VSS signal from it (if your car is set up that way). I had a similar problem after installing a Hypertech chip. I had other problems with the chip in, so I removed it. With the chip installed, I had no VSS siignal to my speedo, since it is electronic, it gets its signal from the ECM. After I removed the chip, speedo operates normally.

 

If the above replys turn up inconclusive... It could be cold soldier joints on the back of your gauage cluster... To check/fix this pull the gauage cluster and have an electronics shop reflow the soldier joints for you. If you are good at soldiering you could also do it yourself. If you do decide to attempt it, you will need a soldier iron, rosin core soldier, soldier iron tip cleaner, and some fluxed soldier wick (just in case). This problem is caused by the temperature of the car rising and falling through the seasons, as this happens, joints will crack and you will loose functionality of your speedo, oil pressure, fuel guage etc... To fix the problem, you will need to reflow the cold soldier joints. It may be a good idea to reflow all of the joints while you are in there though