20G ECU is making me crazy!

fngearhead · Post by **fngearhead** » Wed Mar 26, 2008 10:17 pm

So I blew a headgasket in Oct and decided to swap a 20G into my '91 N/A. The project is in its 5th month because of working too much at my day job. Anyway, everything's installed and I'm down to wiring, which seemed simple because I only had to add about 17 wires for turbo controls and do the cam/crank sensor wire swap. The motor spins over and gets plenty of fuel, but no spark. The codes I got from the ECU 2 days ago were 31, 13, 11...TPS, cam, and crank issues. I verified the location of cam/crank wires and then flipped them back to their original locations and reset the ECU. Then there was only one code, no crank signal. I put my good crank sensor from my old engine in and the ECU seemed happy with that, but then didn't like the cam signal. So swapped that over from the other engine as well. I'm still getting codes relating to cam and crank signal even after swapping these wires back and forth so many times that they practically fall out of the connector. I'm fairly certain they are making contact when they are plugged in. I'm not even positive that I got a turbo ECU with this swap. Wiring is not my specialty, so any words of wisdom would be greatly appreciated. Post back here or even ring my cell, 970-376-3732. I'll be in the garage putting new brakes on my Jeep. I don't think I can screw that up!
Brian

schspeedster · Post by **schspeedster** » Thu Mar 27, 2008 7:04 am

I was getting those same 3 codes on my '93 stock N/A, that ran fine except for intermittent no-start. Could they indicate some other problem like a bad ECU?

Codes persisted even after battery disconnect, then right after checking codes the CEL would blink constantly. BTW I took the car to a Subaru specialist they replaced the ECU, runs OK.

fngearhead · Post by **fngearhead** » Thu Mar 27, 2008 3:51 pm

I tried running it on my N/A ECU with the cam and crank wires in the proper locations for that one. It had codes for improper MAF and canister purge solenoid. The MAF code made sense because old MAF and new MAF are from different makers. It was happy with cam and crank, but still wouldn't run. So I flip the cam and crank wires and hook things back to the 20G ECU, now the one remaining code is no crank signal. I'm going to experiment with the orientation of these 3 wires today after work. Although I have already mixed the order up several times with no results. I'm either buying another turbo ECU or putting this whole mess on tow truck.
Oh yea, thought I'd do Jeep brakes because that would be easy!? Damn caliper siezed on the way home! FUN!!!

Post by **Legacy777** » Thu Mar 27, 2008 7:24 pm

You're having problems because the I/O is not the same for the overseas Legacy/Liberty.

Check out the I/O and you'll see what I mean.

http://www.main.experiencetherave.com/s ... FSM_Scans/

Look for the following file. The link is too long to post
1992_Subaru_Legacy-Liberty_Turbo_(non-USDM)_ECU I-O.zip

fngearhead · Post by **fngearhead** » Thu Mar 27, 2008 11:18 pm

Not sure I follow. Electrical amateur here. I/O ? I'm hooked up just like that diagram shows.

Adam West · Post by **Adam West** » Fri Mar 28, 2008 1:08 am

I/O = input/output...the connection...

Post by **Legacy777** » Fri Mar 28, 2008 1:57 am

So you're hooked up like that, vs. what the US turbo legacy ECU is supposed to be?

fngearhead · Post by **fngearhead** » Fri Mar 28, 2008 4:14 am

Yup, I'm hooked up like all the 20G diagrams I've seen so far. I'm using the 4 channel output to the 20G ingnitor and then running it into 2 channels to use my existing wasted spark setup. My problem is no spark which makes sense because the only code I'm getting now is 11, no signal from crank. There doesn't appear to be any difference in the cam and crank orientation on US vs JDM turbo ECUs. I even switched out the 12 pin connector for the one from the JDM harness as I was wearing it out by opening the back of it so many times.

fngearhead · Post by **fngearhead** » Fri Mar 28, 2008 4:33 am

If it makes any difference in the discussion, the swap is 1989 JDM EJ20G into my US 1991 L 5MT sedan.

vrg3 · Post by **vrg3** » Fri Mar 28, 2008 5:32 am

You can't just connect ignition channels together. You can't use an EJ20G ECU with waste spark unless you build a fairly complex doohickey to handle it.

Adam West · Post by **Adam West** » Fri Mar 28, 2008 5:50 am

Wow, how cool would that be if that worked tho?

fngearhead · Post by **fngearhead** » Fri Mar 28, 2008 8:09 pm

So, ya reckon I should just find a US turbo computer and go back with my old 2 channel ignitor? Are the 22 and 22T ignitors different?

vrg3 · Post by **vrg3** » Fri Mar 28, 2008 8:15 pm

They are not functionally different.

fngearhead · Post by **fngearhead** » Sat Mar 29, 2008 3:15 am

How complex is this doohickey you speak of? What's involved in building it? If I have everything except the ignitor hooked up like the 20G diagram shows, any ideas why my 20G ECU can't see a crank signal? I've even swapped the cam and crank sensors from my old N/A engine to the 20G because I know they both worked. The one remaining code is 11. I've ordered a 22T ECU and should have it next week. I guess it will be the simplest way to get the thing running.

PhyrraM · Post by **PhyrraM** » Sat Mar 29, 2008 3:21 am

Your not the only one, I haven't got any further than you.

This thread may answer some of your questions. http://bbs.legacycentral.org/viewtopic.php?t=35093

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20G ECU is making me crazy!

20G ECU is making me crazy!