90/91 EJ22 with a 92 ECU

glennda5id · Post by **glennda5id** » Mon Dec 03, 2007 6:54 pm

I have a 92 Wagon which has a 90 or 91 engine in it. I would assume an EJ22 (Non-turbo). I am having issues with emissions and in general with the O2 sensor. I replaced the O2 sensor but the code still shows up intermittently. I got the scanner tool software working, and when I initially run the car the fuel trim is at 25%. Then it decides that the 02 sensor is bad and then the trim goes to 0%.

I found out it had a 90/91 engine in it when an injector failed and I went to replace it and found out it was from a 90/91 engine. From what I have read, the different injectors in those years would be the main reason why it would not be a good idea to use a 92 and up computer with a 90/91 engine.

I knew the car had had the engine replaced when we bought it and the kid mentioned something about it coming from japan and having better performance. Could someone identify the engine if I posted pictures?

Does anyone think that the 92 ECU would give me these problems? Should I be able to use any 90/91 ECU (e.g. 22611-AA38X)?

Thanks, Glenn

Post by **Legacy777** » Mon Dec 03, 2007 7:36 pm

Yeah, post some pictures, and yes you need to run the ECU designed for the engine, injectors specifically.

Even though the overall flow rate is the same, the type of injectors are different, and can alter how much fuel is delivered.

I ran 92-94 injectors with a 90 ECU, and the car ran rich. After swapping in a 92 ECU, the car ran much better.

See if you can find some numbers on the engine bell housing to help identify the motor.

glennda5id · Post by **glennda5id** » Mon Dec 03, 2007 8:14 pm

When you swap the ECU's is there any calibration that needs to be done?

I will take some pictures tomorrow and get them posted.

glennda5id · Post by **glennda5id** » Tue Dec 04, 2007 11:17 pm

I did not bother to remove the ECU to verify that it was a 92. But I did hook up the scan tool, and it said it was a 92 N/A based on the PROM ID so I'm going to assume I need to get a 91 ECU. I'm going to buy one on Ebay unless someone on the board wants to sell me theirs.

I am attaching a link to pics of the engine to see if anyone can identify anything else about it. The guy who I bought it from claims it was better in same way. I assumed something like a slightly better cam. I hope it will work well with a standard 90/91 ECU.

Thanks

http://picasaweb.google.com/glenn.hutch ... EnginePics

ciper · Post by **ciper** » Wed Dec 05, 2007 1:42 am

Legacy777 wrote:Even though the overall flow rate is the same, the type of injectors are different, and can alter how much fuel is delivered.

I ran 92-94 injectors with a 90 ECU, and the car ran rich. After swapping in a 92 ECU, the car ran much better.

Does the 90 ECU 92 injector combination work properly besides delivering too much fuel? In other words would this be an appropriate modification for the EJ25 block with EJ22 everything else hybrid so that the increased fuel is matching the increased displacement?

Arctic Assassian · Post by **Arctic Assassian** » Wed Dec 05, 2007 2:04 am

that is an interesting theory.

vrg3 · Post by **vrg3** » Wed Dec 05, 2007 7:11 am

glennda5id - What transmission do you have? That may also matter because 90/91 ECUs were different on manuals and automatics. It's not an idle concern because they also had different injectors, different IAC valves, and different MAF sensors.

So we also need to know a little more about the engine. I can't really tell anything from the pictures, except that it's probably pretty much the same as a US engine.

Do you happen to have a part number for the injector you bought to replace the faulty one?

Oh, and do this for me -- unplug the IAC valve's electrical connector and tell me how many pins are in the connector on the valve.

ciper - You don't need any tricks to increase fueling just because you've swapped in an EJ25 block. The MAF sensor is still reading the correct amount of air.

ciper · Post by **ciper** » Wed Dec 05, 2007 7:16 am

vrg3 wrote:ciper - You don't need any tricks to increase fueling just because you've swapped in an EJ25 block. The MAF sensor is still reading the correct amount of air.

I assumed it might be harder to start because it hasn't read from the MAF yet and would be leaner. Or not?

vrg3 · Post by **vrg3** » Wed Dec 05, 2007 7:39 am

Hm, yes, I suppose you're right about that; the ECU uses a fixed value for the injector pulse width when starting based solely on coolant temperature.

Seems like a silly way to get extra starting fuel to me, though, because it would mess with fueling all the rest of the time. If you actually have a hard time starting with such a swap (which seems unlikely to me), the first thought that crosses my mind is a circuit that decreases the coolant temperature reading while cranking. But it seems unlikely that you'd have trouble in practice; the EJ25 is only about 14% bigger than the EJ22, and our ECUs start really rich anyhow.

ciper · Post by **ciper** » Wed Dec 05, 2007 8:27 am

Yeah I guess you are right. I've been out of the scene for so long that I can't remember most things.

Other than starting is there any other time it ignores the MAF? I know that WOT should ignore the oxygen sensor because I'm going to use an old school S-AFC to adjust the WOT for less black smoke and hopefully more power.

vrg3 · Post by **vrg3** » Wed Dec 05, 2007 3:27 pm

Yeah, I'm finding there's a lot I've forgotten too... it's funny because there was a time when it was all right at the top of my head.

It does ignore the oxygen sensor when the throttle is open more than a certain percentage; it doesn't have to be WOT. But I wouldn't expect it to be running so rich that you're getting black smoke; you sure everything else is okay?

thehookeup · Post by **thehookeup** » Wed Dec 05, 2007 10:22 pm

i ran a 90 ecu on my 93 NA. i passed emissions with flying colors 220k on the motor and never touched the injectors. and i still get great gas mileage with it

glennda5id · Post by **glennda5id** » Wed Dec 05, 2007 11:03 pm

I have an Automatic transmission. According to my research, for 90/91 with AT, that would mean the ECU part number should be 22611-AA380. If I had a manual trans it would be 22611-AA560.

The fuel injector that I put in was for a 90/91. I think the Subaru part number is 1611AA090. The part number for Standard Motor Products is FJ446 for sure.

Honestly I feel like the car is running lean. When I am running the scanner application the 02 reading never fluctuates above ~.7 volts. Also, as stated earlier, the trim is at 25% (the max) after I clear the codes until the 02 code sets, then it goes to 0% and stays there. I understand that there could be something else wrong with the motor, but I think this is a good place to start. I already have done the usual things, tune-up and new O2.

The car does get okay gas mileage, ~25 MPG on a recent long trip but I know it should be better.

vrg3 · Post by **vrg3** » Wed Dec 05, 2007 11:23 pm

90-91 automatic non-turbos had ECUs with part numbers 22611AA380, 22611AA381, 22611AA382, and 22611AA383.

But if your engine's was from a manual, you might need an ECU from a manual. It's not clear whether it would probably work with an automatic transmission, though.

It seems that's moot, though -- 16611AA090 (two sixes) is the part number for a 90-91 automatic injector, and seems to match Standard part FJ446, so it sounds like your diagnosis and treatment plan are good. Yup, just get a 90-91 4EAT NA ECU (22611AA38x) and hopefully your problems will vanish.

If you have trouble finding one, I may have one I could sell you. Let me know if you need me to look.

glennda5id · Post by **glennda5id** » Thu Dec 06, 2007 12:06 am

VRG3, I found one on Ebay for $60 shipped. If you want to part with yours for that amount or less, let me know, otherwise I will grab the one on ebay. Thanks

vrg3 · Post by **vrg3** » Thu Dec 06, 2007 6:13 am

I'll PM you.

Post by **Legacy777** » Fri Dec 07, 2007 7:33 pm

From the pics of the engine, it's from a 90-91 non turbo AT Legacy.....or is equavalent to that.

Short of that....I've been out of this conversation too long....

glennda5id · Post by **glennda5id** » Tue Dec 18, 2007 7:34 pm

So I installed a 90/91 ECU and the car definitely ran differently. The engine seemed to start easier and I do not seem to be getting the O2 code anymore. However, when the engine is under load and the RPM is around 2500 it will consistently start to bog down and then back fire! After a few seconds the computer adjusts it self and all is well. It usually happens while moving at a constant speed, and then pushing the gas pedal a little bit to speed up causes the bog and sub-sequent backfire. Kind of weird. Threw the 92 computer back in there and it doesn't backfire, but I get the 02 code again.

Anyways, I didn't have the laptop scanner software with me so I need to make some runs with that and see if any of the sensors are putting out erroneous information. I'll report back soon.

vrg3 · Post by **vrg3** » Tue Dec 18, 2007 8:33 pm

Huh. Interesting.

Out of curiosity -- if you unplug the IAC valve (warm the engine up first so that it'll run reasonably without an IAC), does the problem get any better or worse?

glennda5id · Post by **glennda5id** » Wed Dec 19, 2007 1:14 am

First off, I got the scanner on the car, and with the 90/91 ECM the fuel trim and oxygen signals look normal. I think the car would pass emissions. Previously the trim would sit at 25% until the ECM flipped the oxygen code and then the trim would go to zero. No way in hell the emissions test would pass in that state.

Anyways, VRG3, I tried unhooking the IAC and it didn't seem to have an effect. The problem definitely occurs when driving at constant speed and part throttle. Any slight change in load, either going uphill, or partially pushing further on the gas pedal causes the engine to start to bog. If the pedal is pushed a bit further, it back fires then starts running fine once the pedal is pushed some more.

The part that I left out is that the PC I use for the scanning is a piece, and its battery ran out before I could run any real tests (<10 minutes). The one thing I did notice is that the load value sometimes doesn't change even when I am pushing the throttle. Can someone who is familiar with the b10 scan tool tell me what the load reading is? ie, is it a direct sensor reading, or a calculation the ecu makes of a combination of sensor readings, if so, which ones.

Do these cars have manifold absolute pressure sensors?

Thanks

vrg3 · Post by **vrg3** » Wed Dec 19, 2007 2:59 am

Weeeeird.

The load number is calculated by the ECU based on stuff like RPM and airflow.

There is no MAP sensor.

Does the MAF sensor reading also not change when it seems like it should?

glennda5id · Post by **glennda5id** » Wed Dec 19, 2007 4:06 pm

Its hard to tell, for a second ignore what I just said about the load not changing. I did some more driving with the computer and the bog/backfire seems to happen when the load number is around 72. I'm going to try swapping the MAF from one of my other cars as a first step.

Post by **Legacy777** » Wed Dec 19, 2007 7:43 pm

Watch your MAF sensor reading and see what it's doing.

legacycentral bbs

A forum for 89-94 BC-BF(BJ) Legacy Owners and Fans

90/91 EJ22 with a 92 ECU

90/91 EJ22 with a 92 ECU

Update