Hey everyone. I just bought a 91 Z28 350 TPI auto and the speedometer isn't working at all. I assumed it would be an easy fix, either the VSS, the wiring or the gauge. Then I started looking around here and kept reading about the VSS input going to a buffer box (which ive never heard of) then to the gauge. If someone could explain to me what/where this buffer box is and also how to begin fixing this, I would really appreciate it. Oh, and no, I have not gotten a chance to test the gauge or check the wiring diagram in a manual yet. Thanks for the help
~Colin

 

The buffer box is only on the TBI cars. I just got my speedo working after converting to TPI. The buffer box's functions are built into the TPI computer, so your car shouldn't have one unless its a converted RS / Z28 clone or something silly like that.
Is the odometer working?

 

I must have misread someone's post and thought it said TPI when it really said TBI. I guess thats what I get for trying to figure things out after midnight. It is a Z28 and no the odometer is not working. Thanks
~Colin