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Definitive EA to EJ wiring guide

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I am attempting my first swap and everything is going pretty well except the dreaded wiring job.

By utilizing the extensive knowledge here on USMB I hope to create a one stop guide to wiring up an EJ engine into an EA Subaru.

My own experience is with an EA81 Brat.

So far I have read many threads, looked at several FSMs and read quite a few wiring diagrams along with Numbchux's guide many times.


I understand that there are several ways to tackle the wiring on a swap of this nature. What is lacking in the guides and threads is clear pictorial guidelines to hooking up what wires from the EJ to the chassis points in the EA. 


This is where I am stuck currently. I have gone the "easy" way and purchased a stripped down wiring harness from General Disorder. It is packaged very well and has the appropriate wires labeled so it should be easy right?


Well, what fuel pump power wire should be tapped? Where is the fuel pump relay? Should the neutral safety switch be grounded? should it see voltage? if it needs to be tapped into the ecu wires, witch one? These are the questions I hope to answer with this thread.

With everyone's help I hope to make future swaps less of a hassle.

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Fuel Pump:

You only need one wire to run the fuel pump.

From the fuel pump relay I ran the fuel pump power wire to a fuse block


top to bottom:

Fuel Pump Power



Start Signal


I ran the pump wire down the driver's side along the fuel lines



And to the pos side of the pump with the neg side going to ground on the chassis. Pump is a replacement for a EA82 GL







It runs! got my switched power a little backwards, switched but off while cranking. One wire change and it fired right up!

So, the engine will run with only 3-4 wires spliced in.

Edited by Rally_Blue
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With just those 4 wires ran to power the car will run.

To get two of the wires hooked up I needed to gain access to the back of the gauge cluster. 


The Tach signal can be accessed at the original fuel pump relay. It is bolted to the chassis just above the hood latch pull cable.

I tapped into the yellow wire




The VSS signal is tapped into at the reed switch behind the speedo. Yellow wire



Coolant temp signal is found on the white round plug. Yellow green wire.


Edited by Rally_Blue

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what year/model is the EA?


what year size is the EJ?

it is easier than you might think, you have one of the hardest parts out of the way getting a stripped harness.


it will make your EA a completely different car, I love mine.

Good Luck!


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So it fired up!


I now need to figure out where to splice the other wires in to get the gauges all working and do it without having to take apart the dash to do so.


Anyone have wiring diagrams for an 82 brat?

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I hook up almost all my wires to the fuel pump relay unit in the carved cars.


Ig. Switched power @ blue/red wire

Tach @ yellow wire

Fuel pump @ blue

Ground to bolt that holds the bracket.


Constant from either fuse box or battery directly (through fusible link and fuse)


VSS will be in a unused 2 prong connector up in far right corner of dash, black connector. Yellow/red and a black wires. Hook EJ vss to yellow black wire and black wire to ground (supplies ground to the vss switch head) this connector was for the optional cruise control. Earlier than 83 may not have this.



Cel Is a red green wire at pin 2 of the round black connector on back of dash. Earlier than 81 may not have the wire but should have the spot inter dash for it.


Ground the auto/mt wire on the ECU, leave neutral wire ungrounded. This is assuming you still have 4 SPd.

Edited by Gloyale
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