Carl B. Posted January 9, 2014 Share Posted January 9, 2014 Just curious about the interchangeability of the EJ harness from different years. Im thinking of getting a fresh harness to make my ej swap look a little more professional. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted January 9, 2014 Share Posted January 9, 2014 What do you have currently? There is some interchange, but not a whole lot. Quote Link to comment Share on other sites More sharing options...
Carl B. Posted January 9, 2014 Author Share Posted January 9, 2014 I have EJ251 engine with all wiring and ecu from a wrecked '01 RS. The salvage yards around here have a few Outback Sports with EJ25 but not so many RS. Quote Link to comment Share on other sites More sharing options...
Carl B. Posted January 9, 2014 Author Share Posted January 9, 2014 I assume something from another MAP car would be best. Quote Link to comment Share on other sites More sharing options...
Carl B. Posted January 9, 2014 Author Share Posted January 9, 2014 Okay, the way I understand it is, as long as I match the harness and ecu I should be okay. Also would have to match cam and crank sensors with the ecu. Can anyone verify if Im on the right trackm I might be better off pulling the current harness out and cleaning it up. Quote Link to comment Share on other sites More sharing options...
Scooner Posted January 10, 2014 Share Posted January 10, 2014 Hey Carl B, on both of my EJ swaps I've completed I basically kept the plug ends that plug into the engine main plugs and cut a foot or two off of the main plugs that come off of the ECU. The rest of the wires I made from new wire, the cam sensors, crank sensors etc that use shielded wire I just installed new. You can find an electrical wire distributor near you that sells it by try he foot. For the throttle sensor I used a shielded cable with 4 wires in it and it all works great. The shielding protects the wires from electrical noise. For the standard wires like for the fuel injectors, power wires etc I'd just use regular 18g wire. I've even thought of going to the pull and save here and taking an ECU, and all of the plugs and making a harness/ECU setup to sell. 1 Quote Link to comment Share on other sites More sharing options...
Carl B. Posted January 10, 2014 Author Share Posted January 10, 2014 Scooner, I think I may do that. Quote Link to comment Share on other sites More sharing options...
peacewize Posted May 3, 2014 Share Posted May 3, 2014 Actually if your feeling frisky the plugs aren't too difficult to take apart so you can swap the entire wire and pin into the new plug. Try it on your old one I had to do this when I botched my first harness 1 Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted May 3, 2014 Share Posted May 3, 2014 Hey Carl B, on both of my EJ swaps I've completed I basically kept the plug ends that plug into the engine main plugs and cut a foot or two off of the main plugs that come off of the ECU. The rest of the wires I made from new wire, the cam sensors, crank sensors etc that use shielded wire I just installed new. You can find an electrical wire distributor near you that sells it by try he foot. For the throttle sensor I used a shielded cable with 4 wires in it and it all works great. The shielding protects the wires from electrical noise. For the standard wires like for the fuel injectors, power wires etc I'd just use regular 18g wire. I've even thought of going to the pull and save here and taking an ECU, and all of the plugs and making a harness/ECU setup to sell. Scooner, I had already planned on doing all further harnesses this way and then I found your post. I am glad to know it works for you. Thanks for the tips. Quote Link to comment Share on other sites More sharing options...
Scooner Posted May 3, 2014 Share Posted May 3, 2014 Yeah of course, it makes the otherwise crazy job of wiring easier and better to understand especially if something goes wrong. It's also nice knowing all of the wiring is brand new and you won't be chasing a broken wire or something hidden behind the fender or up under the dash! Good luck! Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted May 3, 2014 Share Posted May 3, 2014 (edited) Yeah of course, it makes the otherwise crazy job of wiring easier and better to understand especially if something goes wrong. It's also nice knowing all of the wiring is brand new and you won't be chasing a broken wire or something hidden behind the fender or up under the dash! Good luck! For me it makes the time spent at the wrecking yard for parts just a few minutes. I used to have to spend half a Saturday whorking the whole dash out of some moldy junker for $20.00 worth of old wiring. Next, spend another 2+ hours stripping out 90 percent of the crap I didn't really want anyway. Edited May 3, 2014 by Crazyeights Quote Link to comment Share on other sites More sharing options...
Gloyale Posted May 4, 2014 Share Posted May 4, 2014 For me it makes the time spent at the wrecking yard for parts just a few minutes. I used to have to spend half a Saturday whorking the whole dash out of some moldy junker for $20.00 worth of old wiring. Next, spend another 2+ hours stripping out 90 percent of the crap I didn't really want anyway. Wow......Yeah........but then you spend 2 days with a soldering iron and if you confuse any wires you won't know where to start again unless you ping each pi end to end to check wires.... There are also lots of 12v Ig. switched wires that don't come from the ECU......they come straight from the fusebox to the things like Transitor, Coil, EGR solenoid, IAC valve, purge, and Injector power. So those are many items were you need to make lots of juntions out to individual items at the intake. Too much risk of messin things up.....Plus the added expense of wire, solder, shrink wrap.......and If you make it yourself, where do you get all the different colors of wire??? Seems like you'd end up with lots of same color wires going everywhere. IDK.....my mind just doesn't have a problem with wiring diagrahms and big bundles.......I find it WAAAAY easier to strip down a harness that's already setup. 1hour to pull the harness.......1 hour to strip it. Maybe 1 more hour to label everything if I'm shipping it out to others to install. (experience makes it quicker) That way you can still use factory wiring diagrahms. Only reason I would consider anything like this is to delete the SMJ from 90-94 Leggy harnesses. my $.02 Quote Link to comment Share on other sites More sharing options...
Carl B. Posted May 4, 2014 Author Share Posted May 4, 2014 I found it way easier to spend a few hours pulling another harness at the junk yard and a few more stripping it down. Also I had become familiar with the process during my first attempt. I would still like to build a harness from scratch. To do a wire tuck and unclutter the engine bay, but subarus don't wire tuck as nicely as other cars. Also all the "mess" going on under the hood of a subaru reminds me of when I used to work on jet engines. Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted May 5, 2014 Share Posted May 5, 2014 Wow......Yeah........but then you spend 2 days with a soldering iron and if you confuse any wires you won't know where to start again unless you ping each pi end to end to check wires.... There are also lots of 12v Ig. switched wires that don't come from the ECU......they come straight from the fusebox to the things like Transitor, Coil, EGR solenoid, IAC valve, purge, and Injector power. So those are many items were you need to make lots of juntions out to individual items at the intake. You are correct it seems. So far every one I have stripped down has worked too. I have yet to try the other method yet, and I do see your points. Quote Link to comment Share on other sites More sharing options...
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