ransomnotes Posted June 21, 2009 Share Posted June 21, 2009 (edited) I have reached a point where I'm stumped with the wiring of the 83 harness into my 78 z. I think I'm missing something really small like one or two connections I haven't figured out yet (EFI Relay?). I've gone over diagram after diagram after schematic etc. etc. before and during this whole swap process. Most of it has been very confusing because the majority of the write ups have been for a different harness than the 83, and also have been more for 240's and 260's. I did find one write up and a schematic dealing with the 83 harness that helped a lot, but there are still some quite confusing parts. I'm getting ready to move across town and would really love to have this running within the next few days so that I don't have to tow it. Any help would be GREATLY appreciated. All the schematics I've read talk about using the 83 fuel pump relay (didn't do), but the fuel pump is coming on like it's supposed to, but still no start. Here's where I'm at at this point. Coil I'm using the existing 78 - wire to coil for the tach. Not sure where to ground the other end of the resistor shown here. I have it grounded at the dizzy right now. Up next is where the yellow wire and black/white go to ignition switch. Grey covered black wires going to ground. Ignition Switch - Black/White and Yellow wires connected. Here are the green and brown wires supposed to be hooked up to 12v. They are plugged into the spot where the 78 harness plug was. Figured this is supposed to go here since it is going to 12v. Same part of harness as above. Relay says EGI and not sure what the white connector is. Main EFI Relay that was unplugged when removing 78 harness. Edited June 22, 2009 by ransomnotes question answered Quote Link to comment Share on other sites More sharing options...
ransomnotes Posted June 22, 2009 Author Share Posted June 22, 2009 (edited) Ok, I answered my own question here. It WAS the green EFI Relay that needed to be hooked up to switched power. I ran another wire from the ignition switch to the black/white wire under the brown on the EFI relay. It started right up!!! My wife looked over at me as soon as it fired up and we both had HUGE smiles on our faces. There is still some tuning to go like setting the proper timing, TPS adjustment, figure out why my temp gauge is not working now, clean up my wiring job, etc. Well, I'm super stoked now, and I guess this thread could be helpful to some people using an 83 harness in a 78. Edited June 22, 2009 by ransomnotes add something Quote Link to comment Share on other sites More sharing options...
Beau M Posted June 22, 2009 Share Posted June 22, 2009 Awesome job. I will be doing this exact swap in the near future, so I will be hitting you up for pointers most likely. Quote Link to comment Share on other sites More sharing options...
ransomnotes Posted June 22, 2009 Author Share Posted June 22, 2009 Thanks, I'd be happy to help. Like I said, I read all of the swap guides out there, but the majority of them didn't apply so much to a 78 or 83, and confused me even more. I tried to decipher some areas in the 78 and 83 FSM's wiring diagrams, and it did help a bit, but I have a hard time reading schematics. I also made a binder with all the information I could find, and my own sketched diagrams and checklists. Being on a time schedule I just focused on getting the car running. I will go back and clean things up, and make any other necessary modifications later. The things that helped me the most were this thread containing Zeerari's 82/83 guide, FSM's for both cars, labeling both harnesses, taking before pics of both cars, and these diagrams I found Black/White from coil connector to Black/White at ignition switch. The other connection made here at the ignition switch can be confusing because there are three solid yellow wires in the same plug with the Yellow/White wire (that goes into other harness up to coil). The one you want to connect to the ignition switch is to the right of the Yellow/White. You connect that Yellow wire to Black/Yellow at ignition switch. Remove the plug containing the brown and green wires that require 12v constant from the 83's black fusible links box, and then you can just plug that right into the empty socket mounted on your relay box like this Remove Brown and Green plug and plug into here on relay box for 12v constant There are two Black/White, one Black, and one Brown wire coming from the green EFI Relay. You connect the Black/White wire below the Brown one to switched power. The white plug pictured here was not used. These are just some of the things other guides I found didn't elaborate too much on. This stuff combined with the link provided should help a lot. All you need to custom wire to get it going is the coil, EFI relay, main power, power at ignition switch, and grounds. I'm sure if I didn't have the whole donor car this would have been a lot harder. Quote Link to comment Share on other sites More sharing options...
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