I swapped in my 305 TBI and 5 speed from my 92 camaro into my 1987 camaro that originally came with a LG4 carbed engine. I am using the 92 engine harness and computer with the 87 dash harness and guage cluster. The 92 used the VSS sensor in the tailshaft and the electric speedo, while the 87 used the older cable type setup. If I take out the VSS sensor and put in the cable my speedo should work, but my computer will not see the VSS input it needs.

So I need to know what I can do with the stuff I have to let my computer see a VSS signal. I hear this is a very important part that the ECM needs to see for the engine to run correctly. Can anybody help.

 

I can't say if this would work or not but, the older cable driven speedos had the VSS on the back of the cluster/speedo. If you ran the VSS signal from the cluster to the ECM, that might work.
I don't see why it wouldn't since firebirds had an electric speedo and camaros used cable up to '89 and I'd assume there wasn't anything different/special about how they got the VSS signal per same engine combo/year I believe. I don't know.
That's how I'm hoping it will work anyways with my friends '72 truck we're putting a TPI from an '88GTA on.

I'd be rather interested in an answer (from someone with actual knowledge) to this as well. At the very least this is back TTT.

 

First, can somebody explain exactly what the VSS controls? I know about the cruise control, torque converter lockup, and the shift light, but what actual engine function does it serve? My car is a stick and I don't have cruise so I'm curious what the VSS sensor tells the ecm to do to the engine?

Second, could sombody show me a wiring diagram of say a 92 TBI ECM harness and the dash harness diagram that has the guages for a 1987 that came with a LG4?

Thanks