I am nearly finished with my T56 swap in my Z28, and my last item to address is to make the reverse lockout function the same as a factory 6-speed car. The ECM harness on my 93 is very different than that of the 94+ cars. On my 93, pin B1 is a green wire that is used for the reverse lockout. The image below is connector B on my 93 ECM. When I pulled the ECM, there was no wire in that location. Does anyone that has a 93 or has worked on a 93 know if that pin is active on the auto ECM, or only on the manual like the 94+?

 

Same ECM; different PROM.
With a manual PROM, it should feed to that pin of the ECM with the VSS indicating zero movement. Test it. Then add that wire.

 

jmd, thanks for the response on the PROM differences. I have another question for you. I looked over the pinouts on all (4) ECM harnesses and the only differences I see are on connector "B". My 93 auto harness is missing the B1 LIGHT GREEN wire for the reverse lockout wire (highlighted in yellow) while it does have the TCC lockout wire, as well as the 2nd, 3rd and 4th gear signal wires (highlighted in pink).

My question is, now that the car no longer uses the 2nd, 3rd and 4th gear signal wires, should I pull them from the harness and the ECM? I may use one of those wires for power for my reverse lockout so that I do not need to run a new wire to the transmission.

 

I'd be inclined to run the correct colour wire if it was my car.