My speedometer in my 91 Z28 isnt working-- is it possible that i blew a fuse or something? i checked the connection at the tranny and its good- any ideas??

 

No. The VSS is a permenant magnet generator, so it basically makes it's own power (loooosly speaking).

Exactly what did you do to check the connection? Just made sure it was plugged in, or did you test/trace the wires to the ECM?

And just because the wires connect doesn't mean the unit itself isn't creating a signal.

Veryify on a scantool that the ECM is getting a signal. If it's getting a signal, but your speedometer is still not working, look for a break between the speed output at the ECM to the speedometer.

 

I thought the cable might be something else, so i physically connected the prongs together to "complete the circuit" i think i messed it up or something, because before it worked fine..

 

Ew. I'm not sure that hurt it, but that's a really dumb thing to do. Generally electronics need to see some type of load. The technical term for something directly connected across like that without a load is a "short".

But in this case (an AC motor creating this speed signal) that may or may not hurt it. If you're indeed missing your drive gear like your other post seems to indicate, that might be your problem. If you did hurt something in the ECM, then consider it a $30 lesson in crossing wires. Should be about that much to pick up this very common ECM from a yard or auction of some sort.

 

where can I get that drive gear and what is the process of putting it in etc.. do i need it out of the auto tranny? how does it go in?

 

Last time I got a drive gear from a Chevy dealer it cost me about 4 or 5 bucks. You'll have to take the tailshaft off to get to the output shaft. That usually requires disconnecting the torque arm and catalytic converter mounts which may or may not need removal of other things to make room. The driveshaft has to come out, too. Then you squeeze or remove the metal retainer clip and slide the gear off the shaft. Same process to install, and make damn sure that the gear is on in the right place and will NOT go anywhere, because it's fairly common for it not to be installed quite all the way and it'll slide up or down the shaft and either disengage from the driven gear, or get chewed all to hell.

I don't believe the auto and manual gears are interchangable, but it HAS been a while since I've messed with the electric VSS's, so don't take that as gospel.

 

Jza-- thanks for your help- i'll have to call around the local chevy dealers and see if they stock the part- drive gear for 91Z28 T-5-- got it THANKS!!:hail:

 

Did you check the ECM fuse ? The ECM processes your VSS signal. If the ECM doesn't work, then your speedo doesnt work

 

Car wouldn't even run, then..

 

True... I was thinking of my carburated setup! lol