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Older EJ Alt (Gen 1) to Newer EJ Alt (Gen 2+) "Swap"


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9 replies to this topic

#1 eulogious

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Posted 30 December 2011 - 06:32 AM

So my alternator decided to take a dump on me today in my 1990 Legacy LS Wagon. It just stopped charging my battery and gets SUPER hot really fast, like after less than a min of my car running, it's already almost too hot to touch :-\ My DMM also says that while idling I am only getting 11.83v, where a few weeks ago I was getting 13.8v. All my lights we also noticeably dimmer when I got in to drive it. Once I get home today, I will do a couple more tests to make sure that there is not a short somewhere and that all my grounds are good and all my connections are fine. It was too rainy outside when I was trying to do this earlier.

So from the sounds of it, it must now go. And from the looks of it, it might the original alternator, and if that's the case it now has just shy of 165K on it. Not to shabby if you ask me!

Now comes the question of what alt to get, since a new "stock" one for my car cost $135 (seems over priced) from the dealer, and I don't want a reman unit from a chain store since they seem to fail all the time. After talking with a couple of board members off the board and doing some searching on the board, I started calling around to see what I could come up with. I called a "local" alternator rebuild shop, and they wanted $89 for an "in house" (aka not china) rebuild after core exchange. A little pricy, but not too bad for a quality rebuild.

Then GD mentioned the "$70 1997 recall alternator", but with one catch, you need to rewire the three prong plug to a 2 prong plug. Even with the catch, this sounds more promising and cheaper! Supposedly you just call up your local dealer and ask for a 1997 legacy/outback reman alternator, and it should only be about $70 after core exchange, and then rewire the plug. Sounds simple, right? WRONG! Well, it is simple once you find a dealer that won't price ************ you! I had to call 4 different dealers to be able to find one for a good price. 4 stupid dealers! And one of them was going to charge me $201 for the alt (before core exchange)! WTF?

Finally after calling Lithia of Oregon City (thanks GD for recommending them!), I was able to find the correct part for the right price. BUT, they are down in Oregon, and I am in Oly Washington, and I need my car soon. So shipping was not an option, and I was not driving down to Oregon City for a stupid alt. Too much time, and I don't want to pay more for something I should be able to pick up locally.

With part number in hand (Part number: 23700AA34ARA for the reman alt) I called Mike Scraff Subaru in Auburn, WA, since they were mentioned quite a few times on the board. Gave them the part number, and what do ya know, it's $78 after core exchange! WOOHOO! This part does exist at a good price! I then decided to call my local dealer back and see if I could get the "correct" price for this part so I didn't have to drive up to Auburn just for better pricing. Got the parts guy on the phone, gave him the part number, and the price AFTER core exchange... $135! WTF? Seriously? So I told the guy that I could drive up to Auburn and pick this same part up for $78. His response, "Sorry Man". So needless to say I am heading up to Auburn on Saturday to get my reman alt.

Anybody in Olympia Washington that needs parts, DO NOT order them from Hansen Subaru! They WILL and DO charge more for their parts than other dealers. Call up Mike Scarff Subaru in Auburn, real nice guys, and good pricing, so it's worth the drive for sure!

Now that I found my alt, I need to wire up the newer alt to my older EJ. After some searching on here, I found some good info:

http://ultimatesubar...ad.php?t=111657

http://www.ultimates...ead.php?t=97148

http://ultimatesubar...ad.php?t=108154

http://ultimatesubar...ad.php?t=122076

And this one kinda applies, although it's for a Ej swap:

http://www.ultimates...ad.php?t=124891

But no pics or diagrams for EJ to EJ conversion, just EA to EJ, although I suspect that they are close to the same setup. So I am changing that now.

So here's the qoute that sums up what needs to happen the best I think:

"Large white wire: this is where (as you’ve probably guessed) all the current is. This can be connected directly to the positive battery terminal (a large fusible link is a very good idea), but it might be easiest just to connect directly to the large white wire that went to your old Alt.

Yellow wire: This wire is for the voltage regulator. It needs 12v+ when the ignition is on. Very little draw here, so it can come from virtually anywhere. There is an existing wire in the EA harness that will work well for this.

Black with White: This is for the charge light on the dash. It will get grounded if the yellow is getting 12v+ but the alt is not charging. Completely optional."


And here's some FSM diagrams for a 92 (which should be very similar to my 90) and a 97:

92:
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97:
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From the looks of it, all I need to do is wire in the yellow wire to the ignition on circuit (key on), then splice in a plug for the new alt, and I should be good to go. I am correct in this assumption?

So now my next question is... Where in the engine bay would be the best place to tap into ignition power? I don't want to run another wire into the cab, but I can if need be. I would rather tap into a power source in the engine compartment. I will have to research this a little bit more...

The biggest reason I want to do this is because of cost. $78 is alot cheaper than $135 for my stock replacement. It also has the side benefit of allowing me to swap in a higher output WRX alt for a better price as well. I can get more power for cheaper when buying a WRX alt compared to my stock alt. So this conversion will also save me money when I go to a higher output alt.

I should also mention that I will probably be running some 4awg form the batt to the new alt as well, just for kicks and grins. I got the wire laying around, so I might as well use it. So when that's done, I will have done the "Big 3" that is always talked about when upgrading alts.

As of now I have not even removed my dead alt, so once I do that, and re-route the yellow wire and tap it into something, I will take pics and notes of what I do.

More to come soon!

Edited by eulogious, 30 December 2011 - 06:52 AM.


#2 GeneralDisorder

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Posted 30 December 2011 - 01:48 PM

I think - based on that diagram and some threads you linked to.... that the yellow wire is an ignition switched hot lead already - so it's actually supplying power to the alt's VR not being supplied by it. You can verify with a meter - unplug it and check for 12v at the yellow wire terminal in the plug with the key on. It should be hot already. Which means you can simply cut that wire and insulate it. The power to it also supplies other things for the MPFI so just leave it hot. Then connect white to white, black w/white to black w/white and you should be down the road.

GD

#3 eulogious

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Posted 31 December 2011 - 07:03 AM

I think - based on that diagram and some threads you linked to.... that the yellow wire is an ignition switched hot lead already - so it's actually supplying power to the alt's VR not being supplied by it. You can verify with a meter - unplug it and check for 12v at the yellow wire terminal in the plug with the key on. It should be hot already. Which means you can simply cut that wire and insulate it. The power to it also supplies other things for the MPFI so just leave it hot. Then connect white to white, black w/white to black w/white and you should be down the road.

GD


From the looks of it, you are right. I took the liberty of highlighting the wires from some more FSM scans so it's easier to see, and sure enough it should already be hot. In fact it seems to power the fuel pump relay and some other vital things with the motor.

Here's some more scans:

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So it looks like this swap just got a bunch easier :grin: All I need to do is cut the end, insulate it, and match up some wires, and I should be good to go, just like you said GD.

Today when I get off work this morning I am headed up to Auburn to pick up the alt, and then I will slap it in and see what happens. Thanks for the help so far!

Edited by eulogious, 31 December 2011 - 07:11 AM.


#4 GeneralDisorder

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Posted 31 December 2011 - 12:48 PM

Funny thing I just noticed today - the Maxima alts that we put in the EA's use the same plug as the 95 to 99 EJ alt. So if you can find an alternator plug for either it will work for your swap :).

BTW - I'm totally doing this swap on my SS. It makes WAY more sense than buying the round-plug alts at twice the price.

GD

#5 eulogious

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Posted 01 January 2012 - 10:55 PM

Funny thing I just noticed today - the Maxima alts that we put in the EA's use the same plug as the 95 to 99 EJ alt. So if you can find an alternator plug for either it will work for your swap :).

BTW - I'm totally doing this swap on my SS. It makes WAY more sense than buying the round-plug alts at twice the price.

GD


Yup, it's the same plug! I grab one off of an '97 outback, and it totally fits into the maxima alt. I also noticed that the impreza plug is the same as well, which makes sense.

And it totally works in my car now as well! I got it wired in and working yesterday, I just didn't have time to post on the board.

Pics!

New Alt bolted in but not wired up yet:
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New alt and plug wired up:
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All wrapped up:
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And with it running and working:
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I haven't run my 4awg wire from the alt to the batt yet, I will do that tomorrow. Didn't feel like doing that today.

I also needed the new plug, as the old wires won't quite reach. They are just a tad bit to short. So they must have changed the location of the plug slightly as well. Not a big deal since wiring up the new plug is the best way to go about it anyways. The wires being short made me do it the correct way the first time, so that's not a bad thing at all!

And what a difference a new alt makes! I was wondering my headlights were sucking so bad the last few weeks/months, and it's because my alt wasn't putting out the right voltage! With the new alt, my lights are nice and bright again. What a difference. And I didn't even get a bigger one, still just 70amps, but having it be new makes a world of difference! It was time for the old alt to go away, that's for sure!

And if you haven't ever spent the money on good electrical tape, I would highly recommend it! I bought the 3m Super 88 electrical tape, and it's freaking awesome! Well worth the $7 I paid for it. The best tape I have ever used. So if you have just been using the cheap stuff, I would recommend not using it anymore and using some good quality stuff, it does make a difference!

I will post up more pics tomorrow when I get it all wrapped up for good!

#6 eulogious

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Posted 02 January 2012 - 11:06 PM

Alrighty, I got my additional 4awg wire installed, and I decided to blend in the new wire as much as I could...

Pics!

Posted Image

There it is all wired up. I put some split loom around the new 4awg wire, and ran it along side the existing wire, and I think I blends in really nice. It stands out now because it's all shiny and new, but after a few drives up to seattle, it should blend in real nice.

The only real issue I ran into was trying to attach my new wire to the alt. The end I am using was a little bit too big. But this didn't take more than 30 seconds to figure out.

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So I took off the existing nut that was there, and replaced it with a shorter one. Here's the difference between the 2 nuts. It's not much, but enough to let the nut grab a few threads!

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Here's my positive battery terminal:

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I love this thing! It took a little bit of forcing to get 2 4awg wires into it, but they are in there good! Compression fittings are the bomb when it comes to this stuff!

Here's the alternator connection all wrapped up:

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And one more shot of the new wire run:

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Before I ran the new wire, I had a .5v+ drop from the alt to the batt, but now with the new wire, I get a .01+v drop between the alt and the batt. Much better!

All in all, this was a super easy swap, and I would highly recommend doing it when you first gen leggy alt goes out. It's a no brainer to save $50!

#7 eulogious

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Posted 02 January 2012 - 11:21 PM

I guess I should address the 3rd (yellow) wire since I failed to mention it before...

To confirm, the yellow wire already has 12+v to it with the key on. No key on, no power to the yellow wire. I verified this with my DMM, even though the diagrams tell us this already. So all you have to do is cut it, insulate it, and hide it. This is exactly what I did.

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There's the wire before I hid it.

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And here's where I hid it. I just stuffed it into the factory split loom and used some of my awesome electrical tape to seal it up again. This way its safe and out of the way.

It's also a great wire to have handy, since it's powered off of the ignition. Once I add some off road lights to my car, this wire will come in handy. One less wire I have to run into the cab, or splice into!

#8 T'subaru

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Posted 03 January 2012 - 08:33 AM

Interesting thread :)
My jdm '95 wrx loom isnt compatible with my ej20g alternator.

On a side note..and a little late too....Im also tired of partially rebuilt alternators thru retail outlets. The largest automotive electric house in Washington is Romaine Electric, there off hwy 167 in Kent. Ill be sending them an xt6 alt soon to be rebuilt "as new".

#9 Gloyale

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Posted 03 January 2012 - 11:41 AM

Great job.

I hope you put a Fusible link in the 4AWG wire to the Batt. Without one, if the alt has an internal short, or that wire gets grounded any other way, there should be a safety.

The factory charge wire goes through a Fusible link.

#10 eulogious

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Posted 03 January 2012 - 02:28 PM

Interesting thread :)
My jdm '95 wrx loom isnt compatible with my ej20g alternator.

On a side note..and a little late too....Im also tired of partially rebuilt alternators thru retail outlets. The largest automotive electric house in Washington is Romaine Electric, there off hwy 167 in Kent. Ill be sending them an xt6 alt soon to be rebuilt "as new".


I thought about calling them in my adventures of looking, but didn't. Good to know that they will rebuild stuff as well. Good to know about the jdm wrx not fitting into the ej20 alt. Good info to have :)

Great job.

I hope you put a Fusible link in the 4AWG wire to the Batt. Without one, if the alt has an internal short, or that wire gets grounded any other way, there should be a safety.

The factory charge wire goes through a Fusible link.


Thanks!

Now, like I have always said regarding this subject... Yes it is a good idea to fuse it, and it doesn't hurt a thing, but it is not required for safety. If the run is around 18" or less, then it is not required, and a fuse will do nothing really to save me. This is the rule with high output stereo "drag" competitions where the guys run HUNDREDS of amps, all without a single fuse going from the alt to the batt. And these guys have HUGE upgraded alts and racks upon racks of batteries, but still no fuse from the alt to the batt. Of course this is debatable, and I always say its a good idea to fuse, but it's not needed.

My wire I ran might be a little bit more than 18", but I am not concerned about it. I used that same wire in my old loyale for over a year with no issues, so I am not concerned about fire or safety.

The reason the factory cable from the alt has a fusible link on it, is because the wire run is longer than 18", so they fused it. Again, it's not needed for runs around 18", and I don't really care since I ran this same wire without anything bad happening for over a year, so I am not concerned about it in the least in my setup.

But good advice none-the-less! :)




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