legacycentral bbs

So my buddy just picked up a project off Craigslist for $1000, it's a 1997 OBDII Impreza, originally had a 2.2 N/A with a 5MT but the PO swapped a 22t and turbo 4eat tranny in, they hooked it up to the 2.2 N/A Harness and OBDII 2.2 N/A ECU, so it runs pretty rough because it's not the right ECU. What i'm wondering is, wtf do we do? The 22T ECU doesn't fit the blue obdII harness. Is there another obdII turbo ECU that will fit that plug and run the motor better? Or should we get a piggyback and wire it in and leave the N/A ECU?

Also now that it's auto, do we need to change anything on the ECU? like the MT/AT identification? we plan to throw a WRX tranny in there or something other than auto since it's all setup for a 5MT.

Does he have to pass emissions? if no, just run the engine with a standalone. If yes, good luck....

You can't pass DEQ with a standalone???

I suppose it depends on the state. Up here they plug a reader into your obd-II port to check for emissions readiness (to catch people who reset their ecu right before the test, to hide a CEL).

If they just do a sniffer on the tailpipe then his chances are much better of course.

HI,
There are no turbo ECU's that'll work w/the stock harness of the '95-'99 US Subarus. I went thru this my '98 Forester which used the same OBDII ECU as your Impreza....I looked @ Aussie/UK/JDM - no luck.

You're looking @ a piggy-back, stand-alone, or full harness swap.

I ended up using a Greddy Emanage..-sort of-, I installed it, but no one could get it tuned - (P R E included), but I may have also had a mechanical issue.

You can search on here for 'Boostedsubie' as he is running a EJ22T w/a harness swap on his '95 OBDII Impreza.

The ECUs from '95-'98 were the same* for the MT/AT cars - just had a pin grounded depending on the trans. And the '91-'94 turbo ECUs were the same between the MT/AT EJ22T cars...maybe the NA, too - not 100% on that one.


*The '95-'96 harness/ECU was slightly different than the '97-'98 - if you compare the ECU pin-outs.

GL,
TD

I did do the EJ22t swap in my 95 Impreza LX which was originally an automatic and OBD II. I used an JDM Ej20g ecu with the Robtune but this is OBD I of course. I cut off the original ecu plug and soldered the corresponding wires to the OBD I 4 ecu plugs from a 90-94 Legacy and had to add a couple small things. I do not have to do emissions though where my car is registered, if I did, I would most likely fail based on nothing would happen if they plugged into the OBD II diagnostic port, haha. If they did the sniffer, I'm pretty confident I would pass. I had eventually thought of doing a 02-03 wrx harness swap so that I can run OBD II ecu because there are so many more available tuning options.

Thanks for the info guys, very helpful.

BoostedSubie, you have a build thread? I'd like to get the exact specifics of what you did, I think we may be going the route you went for now. You said you cut the OBDII plugs off the ECU and soldered on the 22T ECU plugs to the corresponding wires and 'had to add a couple things' so I would like to know exactly what. This seems ideal for now, to run a Robtune, it will make enough power for what we want. It doesn't need to have the ability to be tuned, if we need to make more power than the Robtune allows, the it will be time for a whole harness swap.

Robert, here is the link to my build thread http://bbs.legacycentral.org/viewtopic.php?f=25&t=52127 I don't know how much it will help you though, it's pics mostly. The wires I had to add were the turbo specific sensors mostly, my car being OBD II already had a MAP sensor and Pressure Exchange solenoid but the MAP is not shielded on it and uses a different connector. That bothered me so I added a a shielded MAP mini harness. I stripped an entire bulk head/dash harness from a turbo Legacy that I had lying around. I depinned the wires from the ecu connectors so that way I would have full lengths of uncut harnesses for individual sensors such as the MAF, MAP, wastegate control solenoid. The pressure exchange solenoid wiring from the Impreza was left the way it was and used. I had to add the wires for the wastegate control solenoid even though I wasn't using it, the ECU will throw a check engine light if nothing is plugged into the connector. You can plug in a resistor to trick the ecu which is what I did but I still ran the wiring in case I ever did want to run the Wastegate control. It uses two wires, power and signal to the ECU. I ran a wire from the wastegate control to the ECU for the signal and I jumped off the Pressure Exchange solenoid power wire for the power. Another thing you will need to add is the Idle Switch to the TPS. The turbo Legacys used a 4 wire TPS and the newer stuff only used a 3 wire TPS, the 4th wire being the Idle switch. But instead of just adding the one wire to the TPS, I used a MAF sensor harness which has 4 wires and is shielded unlike the TPS wiring on the OBD II engine harness. Also since the OBD II engine harness comes out the back of the intake manifold on the passenger side normally, I had to move it to the driver side to avoid the turbo and intake stuff. This required extending a couple things in order to reach such as the passenger side injectors. I'm sure some of this isn't making sense, as I am tired and can't concentrate, lol. So, whatever questions you have, feel free to ask and I will help you out as much as I can.

As it was mentioned, if you have to pass an OBD2 test to register the car, the OBD1 ECU isn't really a good option. However if you don't have any OBD2 tests, then doing the OBD1 swap is probably your best bet. I'd suggest double checking on what the local requirements are before proceeding too far on things.

Just an FYI, the pins may be the same between the two ECU's, so you may be able to just depin the 97 ECU pins and pin them into the correct turbo legacy connector pins. This will save you time soldering. Some may be different, but you may get lucky and most will work.

Definitely, thank you for the information guys. I will post back in a week or two with some updates and pics on how the car is turning out.

I tried depinning the ecu pins. The OBD II pins are larger and slightly different sized and wouldn't fit into the OBD I plugs.

Ok, that's good to know.

It would of made the job easier and cleaner. I originally made that jumper harness but it was a mess because I wasn't sure of how it would all go. Now that I have done it, I'm going to make another one that should be a lot better. I'm currently swapping my 98 RHD Legacy AT with that EJ20h I have. I converted it to single turbo using a TD04. Since it is RHD though, I don't want to go cutting the harness as it would be hard to find another. So, I will use the jumper harness for it, running an EJ22t ecu.

Also swapped it to a 5spd, will be weird getting used to driving a stick on the opposite side of the car.

Nice! Let me know how that jumper harness turns out. Hell, I would pay you for a jumper harness it you were interested down the line.