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EJ Swap Wiring Questions


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#1 ystrdyisgone

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Posted 23 June 2014 - 06:43 PM

Hello folks, I figured I would start a question thread rather than just posting a new one every time something comes up.

 

I've got everything mechanically ready to go :clap: now I'm onto the fun part, electrical.

 

So far I've tapped into the power wires running to the ignition, I've got inline fuses for both switched and constant power. I've also fully disassembled my harness. To be more specific: I've got my ecu with a foot and a half of each wire coming off of it. I got rid of my SMJ, and am planning on running new wire to the engine bay.

 

In the engine bay I've got as much wire as possible coming off the MAF, Ignitor, Knock/Cam/Crank/02 sensor plugs. I also left the engine harness(under the intake) intact.

 

So here are my main questions, does anyone have a list of pinouts for the three grey connectors in the engine bay? I know I could take the intake off and disassemble that harness to pinpoint each wire, but I already installed new intake manifold gaskets, and hooked everything back up to the manifold. I've been searching the web and the legacy manual that I downloaded but haven't had any luck.

 

My other question is related to the fuel pump relay. I see that many people just splice the EJ one alongside the existing EA one. Can it not just replace the existing relay?

 

Thanks ahead of time for any responses!



#2 ystrdyisgone

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Posted 23 June 2014 - 08:27 PM

Well I found this link, which is very helpful. http://www.shoptalkf...p?f=19&t=136053 So nevermind for now!

 

Still a bit confused on the FP relay situation..



#3 ystrdyisgone

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Posted 23 June 2014 - 11:32 PM

I have all the wires from the two larger grey connectors labeled, but not the smallest. Are those all grounds? Can I just tie them into one ground? Or do some have to go to the ECU?



#4 Gloyale

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Posted 24 June 2014 - 11:39 AM

Start over with an unhacked harness.  It is SOOO much easier to strip out excess than it is to put the whole harness back toghether.  Unless you have a BUNCH of extra wiring you will end up with off colors changing end to end at each splice. 

 

Seriously......go to the pick N' pull and start over.  If you want to get rid of the SMJ, do it after striping down everything else and then cut and solder each of the 10 or so wires that are needed and connect them one at a time to eliminate the SMJ.

 

 

 

You've got a nightmare ahead right now.  You also will be losing the sheilded wiring for TPS.  You will also have B#$(% of a time getting 12v from the IG relay to all the various items under hood.....since those don't come from the ECU....they come from the Ig. switched power........yellow wires.

 

One tip...the small connector is not all grounds.

 

You can make the EJ ECU control the EA FP wiring in some applications.  Not in Carbed cars.....and not in MPFI cars unless you ALSO provide new 12v to the EA relay........it's easier to leave the EJ harnesss with the Ig. relay and FP relays wired as they are and just splice the one 12v output to pump.



#5 ystrdyisgone

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Posted 24 June 2014 - 04:17 PM

Thanks for the response Gloyale, I'm aware of the nightmare at hand. That's why I came to you guys! I definitely appreciate your honesty, and I am open to getting a new harness. But I don't have any PNPs near me, and it's very rare to find a subaru older than 98 at my local junkyard. I'm discussing getting a new one through PM with another member currently.

 

But can I really not make this one work!? :unsure:

 

I do have tons of extra wiring, I was planning on matching the colors as closely as possible. I think I have enough to get them all the same.

 

Here are some pics to make it more clear where the "harness" is at:

 

 

 

 

My plan was to keep the shielded wires as they appear to be long enough. If I splice them properly and apply heat shrink will it still retain it's shielding qualities?

 

Concerning getting the switched power to the engine bay, I couldn't just run a large wire from where I tapped in under the ignition, all the way to the engine bay? Or, use the wires under the steering column for the ecu and relays, and tap in somewhere in the engine bay for switched power for those components?

 

As you can tell I only have an elementary knowledge of electrical wiring, but it's seems I have a chance here? Maybe?



#6 Gloyale

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Posted 25 June 2014 - 12:11 PM

Well.....it certainly could be made to work.

 

And yes you can just run wires to the circuits that need 12v.  But there are several, so you'll need to make a split to each item.

 

Do you have the Ignitor? MAF connector?  And Oxygen sensor connector....Those 3 are the only ones that do not go through the main 3 engine connectors.

 

I will try to scan the wiring diagrahm and pinout chart from the FSM.



#7 ystrdyisgone

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Posted 25 June 2014 - 11:38 PM

Well that's somewhat encouraging, I think? Ha

 

This split to each item, is this something that already existed in the intact harness or does it have to be done in that case as well? I'm just trying to understand the difference between what my chop job entails vs just using a thinned harness.

 

I've got the ignitor, MAF, and the O2 along with crank, cam, and knock sensors, those are the wires towards the right of picture number one.

 

I've got the ECU pinouts, and I just found this: http://www.scribd.co...cal-Schematics. Doesn't have the grey connectors listed but I'm thinkin I can decipher my way through this mess with that as a guide.



#8 Gloyale

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Posted 26 June 2014 - 12:37 PM

Wring in a thinnned harness all those 12v wires from the IG relay stay intact........except one that goes to the ALT that ussually gets cut and has to be reconnected.  All yellow wires direct from IG switch and yellow/red wires out of relay to harness IIRC.



#9 ystrdyisgone

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Posted 26 June 2014 - 04:16 PM

Sweet, well I've got most of the wires intact, and the points that they split/come together. So it's just a matter of getting them spliced back together.

 

Still reading up on the alt, I've read people just use the existing EA wiring, may just do that.

 

I've got the harness mostly assembled. I'm left with a few stray wires though.

 

This plug comes off of one of the grey engine plugs. From the wiring diagram it seems this goes to the A/T control unit? Just has a shielded wire so I wanted to make sure before I cut it.

 

These four wires are left loose from the ECU, there are others, but I believe these are the only ones left that I actually need.

 

Left is TACH, I'm guessing I tap into the tach wire coming from my inst cluster for that one. LG/Yellow is neutral switch, leave that open or ground it? Blue/Red is ignition switch, probably dumb of me, but I don't know exactly where that goes, tap into my ignition somewhere? And the other wire is a mystery, yellow/green, from what I've seen in the diagrams it's not supposed to be there, but I also have a mystery wire of the same color coming out of one of the engine plugs:

 

Coincidence?



#10 Scooner

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Posted 26 June 2014 - 06:48 PM

You can tap that tach wire right there onto one of the wires coming off of the stock coil. I'm not right in front of it but i'm thinking its the yellow wire?

Hey, sorry you were having so much difficulty before man i felt awful giving you advice on how i did it because it seemed easier for me. I just figured it would be easier for you as well to run new wires and splice the two ends together (ecu and engine plugs) thats my bad. As far as the other sensors, tps, maf, etc are you going to run new wires for those?

Please for the sweet love of baby jesus, make sure all pf your grounds are going to a good central ground. I used the grounding lug right in front of the battery on the front clip for mine.

#11 Scooner

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Posted 26 June 2014 - 07:04 PM

That neutral is used for nothing in your application, i believe that was originally used to let the ecu know that an automatic car was in neutral.

#12 Scooner

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Posted 26 June 2014 - 08:44 PM

I think that blue with red trace was used for AC in the legacy so you can omit that. What plug and number is that wire?

#13 Scooner

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Posted 26 June 2014 - 09:05 PM

I'm hitting your thread up hard tonight!

Yes, you can splice those shielded wires back together and still have shielding, if you really want to make sure you can take a piece of aluminum foil and wrap it around and then tape it all. All the shielding does is deflect electrical noise from interrupting the wires inside.

#14 Scooner

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Posted 26 June 2014 - 09:31 PM

The temperature gauge wire that goes into the cabin ((at least in my 92' loyale) originate in the engine bay off of the big round plug. The wire is yellow with a green trace, i cut mine about an inch off the plug then spliced in a wire that went to one side of a 270 ohm resistor, the other end of the resistor gets a wire that goes to a ground. It enables the temp the EJ sensor is providing work with thw EA gauge, basically makes the gauge read normal.

I have 24 other resistors if you want a couple haha. I bought them off of amazon and they sent me 25.

Edited by Scooner, 26 June 2014 - 09:44 PM.


#15 Gloyale

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Posted 26 June 2014 - 11:20 PM

That neutral is used for nothing in your application, i believe that was originally used to let the ecu know that an automatic car was in neutral.

 

it will die at stops if you don't have a neutral switch hooked up.  Should be grounded in Neutral....open at all other positions.

 

Fat Blue/red is the starter signal wire....this should be hooked to the starter signal so it gets power with key in start.

 


Please for the sweet love of baby jesus, make sure all pf your grounds are going to a good central ground. I used the grounding lug right in front of the battery on the front clip for mine.

 

You should not need to add any grounds except for the Ig. relay.  All the other grounds happen at the intake manifolld through harness.



#16 Gloyale

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Posted 26 June 2014 - 11:22 PM

I
Yes, you can splice those shielded wires back together and still have shielding, if you really want to make sure you can take a piece of aluminum foil and wrap it around and then tape it all. All the shielding does is deflect electrical noise from interrupting the wires inside.

 

You need to actually connect the sheilding toghether in order for it to have effect.  At the far end the sheilding itself is grounded......without that.....you are just wrapping it in foil to no actual effect.



#17 Scooner

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Posted 26 June 2014 - 11:48 PM

Oh that's funny my neutral switch wire isn't hooked up to anything and my car doesn't die at stops?! Maybe my EJ is possesed?

Tie the shielding together for it to be effective and grounded? Another thing ive never done is ground the shielding and again. HAVE NEVER HAD A PROBLEM.

#18 Scooner

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Posted 26 June 2014 - 11:55 PM

However, Gloyale, you are right about that fat blue with the red trace that does need to be attached to the starter wire, so it get's voltage while starting. I must've misread read my wiring diagram. I tied mine into the wire that comes off the back of the EA starter itself. That little plug that slides on the back of the starter.

#19 Gloyale

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Posted 27 June 2014 - 10:36 AM

Oh that's funny my neutral switch wire isn't hooked up to anything and my car doesn't die at stops?! Maybe my EJ is possesed?

Tie the shielding together for it to be effective and grounded? Another thing ive never done is ground the shielding and again. HAVE NEVER HAD A PROBLEM.

 

Just because you haven't noticed an issue doesn't mean that the wiring is properly sheileded.

 

You can use garden hose for gas line and NOT NOTICE A PROBLEM..............until it's a problem.  I digress.

 

As for neutral switch....If you're ECU is from an Auto car the Nuetral switch doesn't have as drastic of an effect......since automatics stop "in gear" all the time so the ECU trys to keep the idle up.

 

With a Manual ECU...the ECU will cut all fuel when it sees "in gear", throttle at zero, and rolling 1+ mph......If you slip it in neutral without it knowing....it will cut all fuel and you get stalling......It's been experienced by many here......search.



#20 ystrdyisgone

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Posted 27 June 2014 - 04:06 PM

Scooner, what is the "stock coil" you are referring to concerning the tach wire?

 

Gloyale, how would I go about having a wire grounded when I'm in neutral, and open when in gear? Both the ECUs I have are from M/Ts.

 

Also any ideas about that first picture? With the YLW/blk wire and the shielded wire coming off of it?



#21 ystrdyisgone

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Posted 27 June 2014 - 05:25 PM

Okay here's the deal with that stray connector. It takes my signal from the TPS from the white and black wires(shielded), and taps into them to feed into that plug. The plug also has the brown wire feeding in from TPS, and then the plug outputs shielded Black and White, and YLW/blk. And I have no idea where it was supposed to go, only thing that I can think of is the A/T Control Unit. Here's some more pics.

 

And yes Gloyale, I am beginning to see the nightmare I have made for myself... But with the help of my fellow USMBers I have hope that I will make it through!

 

Edit: Oh yeah, pics:

 

HGBIvxel.jpg

 


Edited by ystrdyisgone, 27 June 2014 - 05:33 PM.


#22 Scooner

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Posted 27 June 2014 - 05:44 PM

I was referring to the coil that sits underneath the fusible links. There is a yellow wire on one terminal and a black on the other. If you splice the tach wire into the yellow one your tach in the car will read.


Glo, Glo, Glo...Both of my EJ swaps were from 5 speed Legacies both being year 1990. Meaning I never hooked it up. Ever.. That neutral switch means nothing to this ECU in a manual, how the hell would this ECU know whether the car is traveling 1 mph anyways? Are you sure you're not confusing this OBD I ECU with an OBDII?

This OBD I ECU is not as complicated as it is being made out to be. Geeezus.

#23 ystrdyisgone

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Posted 27 June 2014 - 05:54 PM

Oh sweet, I know exactly where that wire is.

 

Any way you can check out your car and see if you've got that same connector feeding off your TPS? And if so, where the hell does it go?!



#24 Scooner

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Posted 27 June 2014 - 06:03 PM

I wish i could my man, but i went agains't the unbreakable laws of EA to EJ swapping and ran my own 6 conductor wire from the ecu to the TPS for that. So i can honestly say nothing about that plug brother haha. ;)

#25 Scooner

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Posted 27 June 2014 - 06:32 PM

Im out herr looking at my engine and while i can't help you with the extra tps plug, i can tell you that at the tps plug that goes into the tps there are only 4 wires, a brown, black, red, and white.

While i'm here i mine as well tell you that off of one of the square plugs coming from the engine harness there is a white with green trace wire, that is the temp gauge wire, (the one i mentioned about using the 270 ohm resistor) and another wire, a green with white trace. That one is the fuel pressure wire. If your donor was like mine there was no pressure gauge, just a light. Do what you want with that wire.

I forgot to ask but i assumed you have a electrical meter so you can find where wires go right?




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