Quick question:
Is the 93 vtec prelude's ECU mounted "backwards" according to the VAFC install diagram? I'm about to wire up the vafc, but I want to make sure that I'm looking at the diagram correctly. How can you tell if the ECU is facing the right way for their diagram?

 

it should be, when you're staring at the ecu with the plugs closest to you and the other side of the ecu away from you.
Then when wiring into the harness plugs, it should be oriented the same way.

 

when you are looking at the plug diag you are looking at it from the wire side.

my suggestion is to call APEXi and ask them for the color coordination for your ecu. they will tell you which wires from the vafc go to which wires from the ECU. it will make it a bit easier.

 

I understand that I am looking at it from the wire end of the ECU, but which way is up and which way is down according to the diagram? If nobody knows, then I'll call apexi

 

youll be able to unbolt the "top" of the ecu from what i recall
P13 ecu, havent had one in a while. but the clips you have to push down on to pull the plugs out will be on the top side of the plug

 

count the pins on each harness. then match it up with the diagram in the apexi manual. thats what i did. they are not the same amount of numbers on each side. make sure you count the pin inlets and not just the wires because some are not used.