So I'm just laying things out in my head for my swap I plan to do this coming spring in my loyale. After the ej harness is hacked, what do I do with the old ea harness? Do I just unplug the old ecu and the old harness stays for things such as headlights and other misc things? I mean from my understanding the ej harness only has what's necessary to run the motor so it seems to me it has to stay there but I could take it out and clean things up. 

Yes all EA engine wiring stays intact.  No point in removing it all.  Besides it's bundled into the wiring harness with everything else.  The only things to remove are  the ECU and the EA engine/coil/MAF etc.....

 

The thinned out EJ harness weighs about 5 lbs........So it doesn't really add any weight from a practical driving standpoint.

 

NOTE*  For swaps on Fuel Injected EA cars....it is often nessecary to add jumpers from the old EA engine bay connector (body side) to ground.  The pins that have the Black/red, Black/Yellow, Black/blue wires that originally grounded to the EA intake.....these need ground to supply the VSS and the Nuetral switch with ground.  Otherwise the EA wiring can be ignored.

@Gloyale

^^^ Good stuff right there, Thank You

Edited November 22, 201411 yr by Crazyeights

Awesome, exactly what I needed thank you! I plan on doing a bit of alteration to my headlight plugs for my new headlight setup (I think Gloyale posted on that post a couple days ago too) and I just wanted to make sure that if I do work on it that it won't all just be changed when I do the swap. I've also come to find that my alternator isn't putting out enough power to power everything at idle now (I knew this terrible day would come!) so I'm considering retrofitting an ej alt into it now since I have to alter the wires anyway. Has such a thing been done? What would I have to do wiring wise to get the ej alt to work?