SS swap into 95 Impreza LX

[BoostedSubie]

So, i bought a 95 Impreza from work a month ago for an unbeatable price. The car is pretty nice, straight but clear coat is peeling off. I already had my swap planned out before I bought it. I have an extra EJ22t that I'm putting in it . It will be running the 550s, TD05, with my Robtune. My question has to do with the wiring. I've done a lot of reading on other peoples Impreza swaps and everyone seems to merge a Legacy harness with the Impreza harness but I have a different idea. Mine is an LX, which is the first year of the 2.2 I believe and is OBD 2. I looked around for the ecu pin out for it but could only come up with a 97 2.2. Obviously the ecu plugs are totally different, the Impreza is one big one and Legacy is the four plugs. I plan to make a jumper harness which I have already started. Comparing the Impreza pinout to the Legacy one, there are 9 pins that the Legacy harness has and the Impreza doesn't. The Idle Switch(B56.6), Select Monitor RX(B56.7) TX(B56.8), Jurisdiction ID(B56.11), TPS shield(B58.7), Maf sensor pin 5(B58.8), Maf Power(B48.8) TI Monitor(F47.18), Read Memory Connector(B56.12), Trouble Code Output(B56.15). Wondered if anyone had advice on what to with these. Figured i can jump the maf power into another sensor power like tps but the rest i am unsure. I know I should probably be asking this on rs25 or some other Impreza forum but I honestly don't like any of the other forums and trust the advice from you guys. Sorry for the long post.

[BoostedSubie]

I have no clue why those faces showed up

[mike-tracy]

Under the hood should be a sticker saying "This car applies to 1995 emissions for xxx, and is OBD-II or I). Most, like 90% of 95 impreza's were obd-I. A california emissions car might be OBD-II.

Legacy got OBD-II in 95 (most of them, that is), and all Imprezas got it in 1996, which was the first year it became mandatory.

[mike-tracy]

I have no clue why those faces showed up

I clicked "disable smilies" on that post. If you use a lot of parenthesis, some of them correlate to smilies.

[BoostedSubie]

It is definately an OBD 2 car. I guess the LXs were the only ones to get the OBD 2 in 95. It would be a little easier doing this if it was obd 1 but oh well. One of my reasons behind doing the jumper harness is; if in the future I want to sell the car, it would be much easier to return the car to stock and just unplug the jumper and plug in the original ecu.

[Legacy777]

Comparing the Impreza pinout to the Legacy one, there are 9 pins that the Legacy harness has and the Impreza doesn't. The Idle Switch(B56.6), Select Monitor RX(B56.7) TX(B56.8), Jurisdiction ID(B56.11), TPS shield(B58.7), Maf sensor pin 5(B58.8), Maf Power(B48.8) TI Monitor(F47.18), Read Memory Connector(B56.12), Trouble Code Output(B56.15).

I understand you wanting to make the jumper harness at the ECU, but are you running the ej22t engine? If so, there are a variety of sensors that are not going to match up with the existing Impreza engine or chassis harness.


If you plan to utilize or merge the impreza harness at the end devices, (TPS, MAF, etc), here's what I'd suggest:

Idle Switch - I'd suggest running an additional wire to the TPS. I don't see another way around this.

Select Monitor TX - You can ignore this if you don't plan on hooking up to the ECU with a select monitor scan tool
Select Monitor RX - You can ignore this if you don't plan on hooking up to the ECU with a select monitor scan tool
Jurisdictional ID - This pin is either grounded or not connected, so if it's grounded on your current chassis, then just ground it in your adapter harness
TPS shield - You can likely ignore this
Maf sensor pin 5 - This is purely to let the ECU know whether the correct MAF is used. It's simply a power or ground type thing. So you can figure that out and wire it appropriately.
Maf Power - Just hook this up to a 12v ignition source
TI Monitor - You can ignore this
Read Memory Connector - Just hook this up through a connector or switch to ground to read the trouble codes
Trouble Code Output - You can ignore this

[BoostedSubie]

Alright, thanks Josh, that helps. as for the engine harness, i only noticed the tps connector as being different. The maf, knock, injectors, crank and cam sensors, water temp, iac valve are all the same. The tps uses a 3 pin connector though. i haven't decided weather i'm using my ej22t or the ej20h but i'm leaning towards the ej20h for the better flowing heads.

[Legacy777]

Ok, well you can always just run a wire for the idle switch and use the 4-wire TPS connector.

[wtdash]

Subscribed for identical swap info. Mine's a '96 LX.

Since the OBD1 and OBD2 engines/sensors/etc. are so similar I wouldn't think this would be too hard......but...

Since you know (of?) Damian, you likely know he did this swap on his '95 Legacy OBD2 that his son drives. I'd contact him, as he's had some issues after the complete harness swap from a '93 (?) SS, but that may be more than you're intending.

Warning: Your trans should be an AT and won't hold up too long against any Rob tune, IMHO- will that be swapped too?



From what I've read the '95 impreza was an OBD1 and OBD2 car. Those w/the 1.8 and 5-speed were OBD1; the 2.2 and AT were the OBD2, and according to CARS101.com your car must also be an Automatic since that was the only way to the LX that came w/the 2.2 - not 5-speed option.

GL,
Td

[BoostedSubie]

Yeah, its an auto but that is definately going bye bye. I'm using an 02 forester 5mt which is nice since the LXs were 4.11s so no need to change rear diff. I bought the SS chasis from Damien that he used the drivetrain for his swap into his 95 Legacy. The unibody turned out to be bent so I am stripping it back to nothing and getting rid of it. Then putting it all in the Impreza. I'll probably be starting it all next weekend, so may have more questions when i get to that point. I do want to find a better pinout actually intended for the 95 impreza 2.2 because the one i have doesn't show the map sensor but does show the pressure exchange solenoid and my car does have the map.

[Legacy777]

I'm only going to leave this up for a week or so.

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

I can't really verify the accuracy of the info in it, but it's probably worth downloading and checking out.

[wtdash]

Thanks JC.
Td

[wtdash]

I'd like to use one of these from AEM to create an OBD2>>>OBD1 harness, but $150 seems steep. It should make it easy to revert back to stock, if/when needed.

[BoostedSubie]

Thats exactly what i made and for the labor involved, i can totally understand it being that price. The first one I ever made took 5 hours but I've made two more since then and can do it in 2-3 hrs which sounds long but its hard to solder the wires to the metal pins when the pins are so close to eachother. Also, the harbor freight soldering irons suck. Thanks Josh, for the fsm.

[Legacy777]

Yeah.....150 bucks really isn't that bad for the time and skill involved to make one of those plug & play harnesses.

[wtdash]

I'm only going to leave this up for a week or so.

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

I can't really verify the accuracy of the info in it, but it's probably worth downloading and checking out.

ECU (and TCU / TCM ) pinout is here: 1995_Impreza_FSM\DIAGNOSTICS SECTION\ON-BOARD DIAGNOSTICS II SYSTEM\MSA5TCD95I19325.pdf

[wtdash]

Yeah.....150 bucks really isn't that bad for the time and skill involved to make one of those plug & play harnesses.

But - I'd still need to do a lot of merging/wiring/etc. as it isn't an OBD1>>OBD2 converter, correct?

[wtdash]

If you want me to watch rather than opine, please say so. This is your project - not mine. I've done a NA>>Turbo swap on '90, and wired in a Greddy EMU piggy-back on my '98 Forester project, but still suffer from electrical/ECU-ignorance.


If you're going to run the Rob-tuned EJ20G ECU, you need to have the 4 plugs for the ECU to connect to. How are you doing that, please? Do you have pics of what you're doing here? Can't picture it.

What about getting 12-18" of a '90-94 Legacy NA or Turbo harness w/the ECU connectors and connect each wire to its corresponding one on the '96, swap the throttle body for any '90-94 Legacy, which has the correct TPS (the IAC is the same from '93-99), and so many of the other parts are the same between OBD1 and 2, it shouldn't be that hard to just reuse their wiring?


And I assume the wiring 'pins' that plug in to the connectors are not compatible between '90-94 and '95+?


Also, working in the passenger foot well (Impreza) to wire it in is heck of a lot easier than working under the driver's side dash!


FWIW, The ECUs from '95-98/99 shouldn't be much different - if @ all-

EDIT: In '97 the ECU pin-outs changed @ THE ECU, but the wiring on the harness stayed the same.

People use the '95 Legacy/Impreza 2.2 as a direct swap into the '96-99 Legacy Outback, due to the 2.5 HG issues. I put a '95 EJ22 into a '99 OB and it ran great...only had to swap a couple of vacuum hoses.

Td

[Legacy777]

But - I'd still need to do a lot of merging/wiring/etc. as it isn't an OBD1>>OBD2 converter, correct?

If it's just a pass through patch harness, then yes you'd need to do the merging and modification of the adapter harness. But honestly, that in my opinion is fair easier. All I would do is repin the appropriate pins on the male connectors of the patch harness. It should allow for no or minimal cutting of wires.

[BoostedSubie]

TD, the pins are different between the Legacy and Impreza. The Legacy uses two different sizes, big and small, the Impreza uses a bigger one but is different shaped and won't fit into the Legacy male plug. I tried that before making my jumper harness. I ended up getting a extra 95 Impreza ecu, then took it apart, took a blow torch to the mother board to remove the solder and pulled the pins out. I had the Legacy plugs with 6in or wire on them and soldered each corresponding wire from the Legacy plugs to the Impreza female ecu plug. I do want to replace the throttle body with an older Legacy one and make sure it runs the NA engine before I go through the whole process of swapping in the turbo engine and robtune ecu.

[BoostedSubie]

And yeah, the 95 pinout is quite a bit different than the 97 pinout I have. Thanks again Josh.

[Legacy777]

You're welcome.

[BoostedSubie]

I'm still not finding the pin location for the pressure sensor though.

[wtdash]

I'm still not finding the pin location for the pressure sensor though.

One of these on page 59?:

Atmospheric pressure sensor E29 23
3.9 — 4.1 2.0 — 2.3 —

Pressure sources switching solenoid valve E29 58
ON: 1, or less
OFF: 10 — 13
ON: 1, or less
OFF: 13 — 14

[wtdash]

I ended up getting a extra 95 Impreza ecu, then took it apart, took a blow torch to the mother board to remove the solder and pulled the pins out. I had the Legacy plugs with 6in or wire on them and soldered each corresponding wire from the Legacy plugs to the Impreza female ecu plug.

RU referring to removing these wires that go from the ECU's board to the yellow connector? This is one I sold last year: