new member, looking to swap

[fastwagn]

hi guys, i purchased a 1991 legacy turbo sedan after several years of hunting. i bought a 2.2 solid deck turbo block for my forester build and it conveniently came with a car wrapped around it. after sinking money into the auto (missing teeth on the ring gear), i have an ej20g and 5sp. to go in. i just read the post on the 5sp swap (VERY thorough) but need a source on an ecm for the EJ20 and possibly a donor harness (or is the harness even necessary?) thanks in advance for the help guys.

ryan

[555BCTurbo]

Just run the EJ20G off of the EJ22T management...it's so much easier that way

[dropdfocus]

Yes, BXSS is doing that with his car and I think Livestrong is doing the very same too.

BTW, welcome to the Legacy Central forum!!!

[fastwagn]

no problems with iac or coil on plug, thought i saw that in other threads,. any issues with using the auto ecm with a 5sp? later subarus will "run-on" when you let off the throttle.

[dropdfocus]

Wow, the newbie is far from Subaru stupid. That's a great relief! Glad to have another thinker on the BBS.

[555BCTurbo]

no problems with iac or coil on plug, thought i saw that in other threads,. any issues with using the auto ecm with a 5sp? later subarus will "run-on" when you let off the throttle.

IAC is no problem...and you just run wasted spark (with 1996 Outback Automatic Plug wires) instead of coil-on-plug. The manual and auto ECUs are the same...the only thing you have to do is clip the "ecu identity" wire when going from auto to manual.

[fastwagn]

thanks for the info. hate to run the old style coil pack setup but probably cheaper in the short run. will the ej20g ecm plug into the harness or will i have to hackand splice or merge if i find one later?

hopefully i'm not too dumb since i've gotten paid to do this for 6 years

[PhyrraM]

To use the Ej22t ECU you install the original Ej22t intake manifold harness on to your Ej20g, fabricate a coil bracket, extend the IAC wires and then just plug everything in.

There are many testimonials on this board about how well this works after the initial ECU learn procedure. I don't doubt them. Even if there are a few spots that need adjusting an AFC (even the older ones) will do the trick.

Once everything is running and you decide you still want/need more, then an upgrade back to coil-on-plug and the addition of a Power FC (or Ej20g ecu) is only 2 wires away.

[555BCTurbo]

Once everything is running and you decide you still want/need more, then an upgrade back to coil-on-plug and the addition of a Power FC (or Ej20g ecu) is only 2 wires away.

I don't think it's that easy...

You also have to do some harness re-pinning

[PhyrraM]

True, my 'two wires' refers to adding two complete ignition circuits.

For me this composed of the following...

1. Stripping a regular Legacy harness of the complete ignition circuit consisting of two wires from the ecu to the ignitor, the ignitor connector, the ignitor itself, two wires from the ignitor to the SMJ Connector, and two wires from the SMJ Connector to the engine bay>intake manifold harness connector. All of these wires were removed from thier connectors preserving the pins, i.e. no cutting.

2. Placing all the above into my Legacy SS. I chose to remove the dash and fender, unwrap the harness, add all of that in factory style and rewrap the harness. There is really no need to integrate that completely, in fact I don't think I would do it again.

3. Fabricate a mounting bracket for the second ignitor.

4. Make your Engine Bay>Intake manifold connectors match. Yes, this is a bit of re-pinning.

The only other difference of note is that the WRX Ej20g uses two radiator fan outputs. The Legacy/Liberty Ej20g uses that second output for the I/C pump. The USDM Ej22t doesn't have a pin there. The end result is it's a non-issue.

Also if/when you switch to Ej20g based ECUs you need to switch to a "plastic" AFM from just about any '92-'98 Subaru. A regular Legacy or Impreza one will do just fine.

[fastwagn]

excellent replies guys. thanks again. i am really intrigued at this post (and others) that refer to using dual ignitors rather than sourcing the japanese unit for the coil on plug, elaegant solution for sure. i need to save this and several other threads. for now, since this will be relegated to being a not so boring daily driver i will most likely cheap out and use the existing ecm. i'll have my hands full enough swapping in the ej20 and it's 5sp. now for some curveballs...
i have used engiuty extensively to tune all manner of more modern subarus. i am under the impression that the older ecms (v4 wrx) and older do not have flashwrite cpabilty, how much luck are you guys having with the afc? the learning function of the newer subaru stuff has made these spotty at best in my experience (i know people that had to clear memory or do cpacitive discharges every few weeks to get the afc back into range) on the other end of the spectrum my friend's s14 runs like factory with an older afc. thanks again guys. it's refreshing to meet crative, intelligent, and most of all helpful forum folks.

[PhyrraM]

Older ECMs use Eproms. The EJ20g series of ECUs have been cracked and there are many different guys (Europe and Aussie/New Zealand) offering chips. I assume the same for the Ej20K series also. The Ej22t ECU uses eproms for that matter. Nobody has cracked it yet, but some have worked on it. Unfortunatly it's above my head to try.

I have no experiance with 'piggybacks'. I was going to try a S-AFC and ITC, decided to just go with a Power FC. The EJ20g PFC is now discontinued, but it can still be found if your diligent.

That's my plan exactly. I plan to get it running on the factory Ej22t ECU and ignition. I will then convert to coil on plug and the PFC later. I added the wires to the harness, but untill I actually plug in the second ignitor, none of the circuits are completed. This makes the whole setup transparent until I swap the ecu (PFC) and the Ej20g intake manifold harness into the car.

Now I just need to stop this inssesant house hunting and get the car back together.