so I just finished swapping in the T-56, got the speed sensor wired to the PCM, but not real sure how to wire it to the speedo. The car was originally a TBI car, so it has the stupid VSS buffer. I know on the 4th gen's, the wires coming from the VSS are yellow and purple with yellow being the signal and purple being the ground, and after looking at the 3rd gen diagrams I am assuming it is the same way. If so, I'm going to splice the VSS output from the PCM into the yellow 3rd gen VSS wire which will input directly into the VSS buffer and everything should work normally. This sound right to anyone else?

 

I just did this myself tonight, there is a green/white wire coming out of the PCM that goes to the speedo. What I did was pull the buffer box and toss it, then ran a wire from the green/white to the green/black in the cluster harness. If you have the purple and yellow wires going to the PCM the green/white is the output wire. The purple is ground and the yellow is signal which go to pins 31 and 32 on the red PCM connector. The green/white is on pin 8 on the black connector on the PCM. Might be wise to hook up the reverse shift solenoid also which is pin 6 on the blue PCM connector and have the skip shift programmed out of the PCM so it won't throw a code if you already haven't.

On the 92 Camaro, it shows to be a tan wire on the buffer box, but it showed this on my 91 Trans Am cluster as well, but it was green/black