Well lets start here:
Wiring instructions for 3800 Series 2 SC engine swaps into a Fiero using OBD-2 PCMs - Pennock's Fiero Forum:
https://www.fiero.nl/forum/Forum2/HTML/093879.htmlThen move on to here:
3800 swap harnesses - Pennock's Fiero Forum:
https://www.fiero.nl/forum/Forum2/HTML/087655.htmlAnd finally here:
Quoted from a post by 86GT3.4DOHC
"Step1: Remove ALL of the tape, loom, and attachments
Step2: Disassemble the back of the junction/fuse block and remove the plugs, toss the block aside. Now there should be some blue plastic strips on the sides of the plugs, you will want to slide those out, as they secure the wires into the plugs. Then pull all the wires out, pay no attention to where they go. Do not cut anything yet. You will notice that many of the individual plugs have 2 wires going into them, you do not want to cut those yet unless you have to. What you will run into if you do is you will be wiring the harness, and come to this cut wire and ask yourself "was this supposed to plug into the ECM or the block?" because you never know what might have been cut improperly in the past. You will have to cut some of the pairs to untangle them though.'
Step3: Remove all the crap that plugged into the block that does not go anywhere now. Don't cut stuff, you might need long lengths of whatever color wire in the future, so save it.
Step4: Remove all the wires from the PCM connectors. Now I did not label these in any way, its pretty easy to get them back in right. You will want to start by removing the plastic covers from the back of the plugs so you can see where the wires go in. then you will need to cut or remove the washer from the front of the through bolt, it holds the halves together. Then, slip the clips in the back of the metal that hold the plastic front on and remove it. You will then need to poke in the cracks on the sides of each nose cover (the blue and clear pieces) and pop them off, DO NOT loose or damage them, they actualy hold the wires in place. Then start pulling wires out, you will need a knife to slightly pull the little plastic fingers back while pushing the metal plug away from the center and down. Pull all the wires out.
Step5: Go to the store and buy 3 rolls of electrical tape and 200 small wire ties (I bought 100 and ran out) as well as some tags, I had some from building the house with little strings and tag faces for construction wire labeling. You could use tape if you had to. You will also need about 5' of heat shrink tubing about 3/32nd ID, a soldering iron or gun, and solder, a little solder assistant with two alligator clips on a mount to hold the wires helps, also some masking tape and a sharpie.
Step6: remove each sensor/etc plug from the giant mess one at a time. Coil its wire and wire tie it into a bundle, label it using the PCM pinouts, matching the wire colors to the use. Many wire colors are repeated, so be careful in the future. You will run into some 2 to 1 plugs from the junction block, you will need to cut these now, you might want to label some of them, but all pinks are 12v, and that's what most of them are so you should be okay.
Step7: Sort through the plugs you don't know what they are. Most of them just fall out of the harness, I think I had one light green wire go from the tranny gear selector switch to that weird 2x3 grey square block. After exhausting options, I just cut it and worked it into the harness in case it was important later. Most of the others you will find go to cut off wires that someone sliced in engine removal, Im assuming we wont be needing any of those. Set those plugs aside, but dont loose them in case we need them later. You will have at least one 2x3 grey plug, a round plug all but identical to the tranny's connector, a black rectangle I think 8 or 10 pin plug. All those aren't used.
Step8: Once you have all the important plugs and unused plugs removed you will find several wires that don't go to plugs, but instead ran from the PCM to the junction block, those are mostly sensor outputs or PCM feeds, coil them all together and set them aside. You will also have a couple of odd balls like the alternator wire, I suggest bundling and labeling it too, as well as the rest. If you keep everything bundled it will be much neater and easier to work with. Labeling everything helps because even if you know what something is now, day after tomorrow you don't want to have to look it back up after staring at miles of wires for hours on end.
Step9: Now I guess unless I forgot something this is where we start building the harness. I picked the easy stuff first, the rear injectors. Start by plugging them in, then cut the first wire tie, then run it to the next injector, wire tie the wires together to hold shape, then cut the second injectors tie and run both to the next and tie, then cut the last injectors wires loose, and run them to the front of the engine tying every 6 or 12". The firewall passthrough is very near the front engine lift point, so I tied all wires to this. Then add another section of plugs, EGR, Evap, MAP etc and repeat. Always tie to the closest wires, and tie a lot. tie as you run allong other tied wires, you will end up with 5 or 6 layers of tied wires tied to other tied wires, this is okay, keeps everything tight and neat. When you are done you can remove the harness from the engine and it will hold its shape if you tied enough. Then start at one end and wrap it tightly with tape, only cutting the ties as you come to them.
Step10: I recommend running the 3 tranny connectors, and 02 on the left of the engine, then run all the others around the front of the engine, seemed to fit best this way. I wrapped the alternator wire right into the harness, and the main ground harness. I ran those two down over the AC compressor and ran them with the main battery wires to the battery area. I would not splice them in as redundancy is very good.
Step11: once you have a nice neat harness leading to a giant ball of mess where the PCM would be, you are in good shape. I would test fit the engine and make sure you're shortest wires are going to reach the PCM where you want it. Then take it all back off the engine, and take it inside.
Step12: From here I made 4 distinct paths coming off the harness
1:wires not yet sorted
2:wires that don't go to the ECM
3:wires to clear plug
4:wires to blue plug
I use twist ties to hold them as far up the harness as I could to keep them clean. you dont have to make them at first, just remember to sort as you come to them
Step 13: Begin sorting. Pick your shortest wires and do them first, you will need a continuity tester and a jumper wire with alligator clips. Clip to the first wire and look up its color in the PCM output. When you find what its supposed to be, test continuity to this plug. Remember many wire colors are repeated. Once you figure it out see what connector and pin it goes to
Step 14: prepping the PCM connectors for use. The black holey pieces need to be inserted from the front of the PCM connectors, inside the shell. Then take your white pieces and put the rubber gaskets back in, make sure you put the right one in the right connector, as you can use them for error checking later, obviously you shouldn't put a wire in a hole that wasn't used before. Do not put the clear or blue caps on yet, the wires wont go in with them on. Also dont clip the white piece into the metal shell, you cant force the wires in like that, leave a couple of inches space. As you are inserting the wires make sure you do not cross other inserted wires, you don't want a tangle in the connector. The backs of the metal shells are numbered so it should be easy.
Repeat step 13, sorting out wires that don't go to the PCM as you go. I recommend not tying the engine and tranny harnesses together at first, as that will make determining which pin it goes in much easier, then once you do all the engine ones, put the tranny side on.
Step15: after you have ALL of the wires in place and the 2 connectors separated clear back the the harness split. Go through one by one cutting out the longest, slip on some heat shrink tubing, solder the ends back together and heat shrink. I did not cut down every single wire, just the really long ones."
That's it. That will be $50 please.
I will PM you my paypal account info.
[This message has been edited by Bubbajuju (edited 09-13-2008).]
