EJ20G into '91 Turbo Legacy SS - Complete Swap Writup (PICS)

[Natoe]

update? can you write up how you ended up adapting the ignition? the ej22t in my impreza is getting slow and acting like it wants to blow up...
thanks!

[BoostAddict]

...Lol.
The swap is 90% done. I haven't had the time to finish it yet, because I've got to study for my exams. I'm getting my degree at the end of April, so I'll have more time then

All that still needs to be resolved is adapting the JDM MAF. I've got two of them at my house right now, just not the time to drive over to my mechanic's shop to wire them up.

Other than that, the wiring wasn't that bad. Along with the PDF's of the EJ22T and the EJ20G wiring, we were able to draw up a diagram of how to hook it all up in a few days. I'll be posting the wiring instructions as soon as I start the car up (end of April).


Cheers!
P.

[EJ20TMAN]

My real JDM legacy GT/RS AFM is 5 pin, so is the early WRX ones, im going to say that is a non turbo impreza AFM

[BoostAddict]

EJ20TMAN, are you saying that the JDM 6-pin MAF that I have is not the right one and it won't work? I thought that any JECS MAF would work. Someone please clarify this...

P.

[Natoe]

update please! i am curious what exactly you did for wiring up the coil on plug ignition?

the part number on that MAF looks like its for an SVX (?) did this end up working?

[Do It Sidewayz]

i ended up using the JECS MAF sensor off a 95 Legacy Wagon. Works just fine.

I had the car running without a problem and no check engine lights.

I used 2 legacy turbo Ignitors to fire the Coil Packs.

[Natoe]

awesome thanks! i have the correct MAF then, just need another ignitor.

[BoostAddict]

The car's now running strong on all 4 cylinders. What we ended up doing was scrapping the SVX Ignitor / EJ20G Ignition Coils idea and we just hooked a set of 2002 WRX Ignition Coils (without an ignitor), as per this post on NASIOC:
http://forums.nasioc.com/forums/showthr ... ?t=1192028

The SVX Ignitor was causing only 3 EJ20G Ignition Coils to get signal and as soon as we unplugged it, we were able to get all 4 signals. We then hooked up all of the new WRX Ignition Coils in the right firing sequence and the car started running fine. It now idles smoothly and revs up without hesitation.

We've got one last thing to resolve before the car's back on the road. One of the sensors seems to be hooked up incorrectly, because the car sputters at ~3000-3500rpm. It revs up to that point quickly, but at over 3000rpm it hits something that sounds like a bit of backfiring and it won't rev any higher. If anyone has any suggestions on which sensors to check, it would be appreciated. We'll start with completely re-wiring the JECS MAF, but what other sensors could be causing the ~3500rpm cut-out?


I hope to have an update with the car on the road soon!
P.

[BoostAddict]

We've verified the following today:

- The car is running on all 4 cylinders
- Spark is on all 4 cylinders at the right time (using the USDM WRX Ignition Coil conversion with 4 brand-new WRX Ignition Coils)
- Injectors are working correctly on all 4 cylinders (we replaced the current EJ20G injectors with a new set just to make sure)
- The JECS MAF is sending the right signal (no CEL code when the MAF is connected, but the MAF code shows up when we disconnect it)
- The TPS is sending the right signal (no TPS CEL code)
- We even checked for a plugged cat by disconnecting the downpipe and letting the exhaust gasses straight out.

The engine is running worse with the MAF connected. If we disconnect the MAF, it idles smoother and doesn't stall. If we connect the MAF, the engine has a harder time getting up to revs and sometimes stalls.

If anyone has any suggestions what could be causing this EJ20G to cut-out and backfire at ~3000-3500rpm, please give us ideas... 'Cause we're running out of them and we'd really like this '91 Legacy Turbo with EJ20G Engine + ECU back on the road


Thanks in advance,
P.

[BoostAddict]

We originally thought that a bad MAF was the problem, but we tried 2 different JECS (green) MAF's, tested both of them on a stock '96 Impreza 1.8 and they worked correctly on that car.

Could someone confirm that the EJ20G ECU will accept the Vehicle Speed Sensor signal from a '91 USDM Legacy Turbo cluster? Or do we need to modify the Legacy cluster in some way to send out the correct VSS signal to the EJ20G ECU?

What kind of a VSS signal should we see when the car is standing still? From what I've seen so far, it's getting O when the car is not in motion.

If anyone has any suggestions on what else could be causing this 3000-3500rpm engine cut-out (that feels like a limiter), they would be appreciated.


Thanks,
P.

[BoostAddict]

UPDATE:

Today we've hooked up the EJ22T ECU and ran the wasted-spark setup on the EJ20G, just like on the original EJ22T. We used the original EJ22T MAF, EJ22T Coil-Pack and the original EJ22T ignitor. Engine fires up, doesn;t really want to idle with the MAF conected and shows the same symptoms as before:
- engine starts cutting-out at ~3000rpm. It backfires and revs go down.
- tachometer starts "jumping" at higher revs. It's even more noticeable now with the

Our conclusion:
- cam & crank sensors are probably faulty. We cast our votes for the crank sensor. I'll get both of these sensors new from the stealership tomorrow and we'll see if that solves our problem.

Does that sound reasonable? Did anyone encounter problems like this because of a faulty cam or crank sensor?

Cheers!
P.

[legacymax]

I had trouble with my ej20G ecu conversion(part of it was a faulty ecu pin) and ended up putting the t-leg ECU back in and spliting the spark signal to the cylinders and keeping the USDM WRX coils and not running an external ignitor. The car electricly is running fine now. I thought it was my Cam and crank sensors but they ended up being fine. But it is worth trying a used set. I would not buy them from the dealership because it is going to empty your pocket.
-Max

[BoostAddict]

legacymax, that's an interesting idea. Could you post which ignitor signals from the ECU you spliced and ran to which cylinder?


Thanks,
P.

[legacymax]

legacymax, that's an interesting idea. Could you post which ignitor signals from the ECU you spliced and ran to which cylinder?


Thanks,
PC

I don't have my car close to me right now( I wanted to push the car off a cliff so I had a friend finish it) and it was a while ago since I worked on it but if you look at the t-leg pinout sheet, it should tell you what pin goes to what two cylinders. Hopefully that helps a little. That also made it easier to go back to EJ20G ECU if I get the guts to try that again.
-Max

[BoostAddict]

Lol... What problems were you having, that prevented you from running the EJ20G ECU and made you decide to leave the original EJ22T ECU and make it run with the EJ20G?

We were able to hook up the EJ20G ECU using the stock EJ22T wiring harness to the EJ20G engine. The only problem is that it won't rev over ~3000rpm. It backfires and hits something that feels like a fuel-cut... We're suspecting faulty Cam/Crank sensors, so we'll check these tonight. Did you run into trouble like that in your swap by any chance?


P.

[legacymax]

Never had a chance to get to that point. I got it to run on 1 and 4 cylinders but it would not fire 2 or 3. I ended up having one(possibly two) bad ecu pins but since I went back to ej22t ECU, I never cared to find out if it was two. My friend tyler swap out the ecu pin and it runs now but the headgaskets didn't seat properly so that is my problem now. Now I just want to get the thing driving and do a good couple month long shakedown on the thing.
-Max

[BoostAddict]

PROBLEM FIXED!!!!!!!!!

I've just replaced the stock EJ22T Cam/Crank sensors with the USDM Impreza 1.8 N/A ones and now the engine revs past 3500RPM up to redline. It pulls hard and doesn't backfire!

If anyone ever encounters the same problems as I did in my EJ20G conversion, do the following:
1) USDM Ignition Coil conversion
2) Fresh set of working Crank/Cam sensors

...We have one more problem to resolve though. Teh car won't idle with the MAF connected. We're using the green JECS one from the USDM Impreza 1.8L N/A. When we disconnect the MAF, it runs no problem, but with the MAF connected it stalls on idle. We're tried 2 working JECS MAF's so it's not the sensor. We've checked the continuity on the MAF/ECU wiring as well.

If anyone has any ideas on how to proceed and to fix this idling problem, please give us a shout!


Thanks!
P.

[ericem]

Hey boost. Are those g-power plugs only for the turbo motor? I tried them in my 2.2 NA and I get only 300-400km a tank with a light pedal and I get a little bit of hesitation. I got them from subaru missisauga for 1.50 each so I don't really care if they were wrong. I think im going to try the V-powers I bought.

[BoostAddict]

Another leap forward.

The car now revs up to redline smoothly and idles at ~1000rpm. We've hooked up the JDM STi 3-wire MAF and that solved the idling problem! It's weird how everyone was telling me to use the 5-wire Green JECS Impreza 1.8L N/A MAF with the EJ20G Engine + ECU, while the 3-wire JDM STi MAF seems to be the right one with my setup. I guess the ECU that I have must be a JDM Impreza WRX ver.2 one and the right MAF for it is the 3-wire now.

The only thing is that the car now runs way too rich at idle. I guess we'll have to tune it now.

Other than that, everything works 100%.


P.

[SubaruNation]

pics are dead

[Subiel94]

Where wld you you even get that wastegate control solenoid valve and a pressure exchange solenoid valve? For a 94 Subaru legacy turbo 2.2

[Legacy777]

You can post a WTB thread in the parts shed or try and find them at a junk yard. I'm not sure you would be able to buy them new from Subaru.