Originally Posted by tbramich
uh oh , dont have the pc. thought i could just swap the stuff over and it would work. ill see if the guy still has the pc, anyone have a link to how to splice it in?
If you get the PC and the harness from the new motor...You can just cut the whole cable that goes to the 89 computer at the firewall ...(about 1/2" diameter about in the middle of the firewall) after you take the battery cables off. Remove the rest of the wiring from the old TBI motor labelling the wires from the sensors and anything that goes to the big block connector by the brake booster. I've got a list somewhere that has the wiring colors and what they should go to from my swap but will have to find it. ALL of your factory gauges will still work with the 94 but I think I had to swap over a couple of sensors from my 88 to the 94 for it to work. I mounted the PC by the brake booster and washer bottle securing it to the support rod.
You can also put the MPI harness on a diet by removing any wires not needed as well. Just follow them out and make sure they don't go to anything your going to need. I got rid of all the fuel pump wires and a few others as I kept the 88 harness wires that went to that.
It sounds very intimidating but don't be afraid of it. I went from this rats nest of wires...
I know this is from my Vortec swap but the MPI 2.5 is almost a stand alone install using the MPI harness. Only wires you really are using from the TBI are going to be the ground, Ign and power wires. Just about all the other wiring will be from the large block connector going to the starter and gauge hookups.