hey guys...i have a 1991 Z28 with a TPI and auto trans...at the connectors that go into the ecm what wire is for the speed sensor pulse?? im trying to wire up a kill switch for the speedo...but all i can seem to find is articles for tbi vehicles...can any1 help me out??

 

I have a wiring diagram for my electronic dash in my 88 TA. It shows that the wire from the speedo to the speed sensor (don't know if it runs into the pcm as the same color or not) but it is light-green and black.
Let me know if that helps or not.

 

I believe you are going to have to kill the speed sender all together, which is the purple and yellow wires going into the ecm, the tbi one they go into the buffer box and you can cut the ecm feed off without killing the speedometer, with tpi you're going to have to lose the speedometer also.