Turbo wiring questions

[THAWA]

So I'm looking at the harness and stuff and all the wires, trying to figure out whats going to be the easiest way to do this without cutting anything.

First thing I noticed is that all three of the main connectors between the intake manifold and the fender wiring are the same on my 90 NA and this 91 Turbo. This makes me think that so long as I just swap the Turbo intake harness and the turbo ECU all the wiring will match up. Does this sound off base or am I right on that?

Then I wonder about the wiring on the ecu connector. I understand that there's extra wires for the MAP, Pressure Exchange, and Wastegate in the turbo setup. Does anyone know if the wires are run from the fender connector to the ecu connector on an NA car?

Another thing I've been wondering is where are the wires for the MAP, PE, and Waste run? I don't recall seeing extra connectors on the intake manifold harness and I dont have the full turbo harness to go look at either.

I think that's all for now.

[vrg3]

I don't know if the wires are the same or not... If the colors are the same that's a good sign, but I'd say don't assume they are. You'd actually be best off swapping the harness from your stock intake manifold onto the EJ22T intake manifold, and then adjusting the temperature sensor/sender wires if necessary.

On 92-94 models at least, the boost control and pressure exchange solenoids have only the SMJ between them and the ECU. And the pressure sensor wires go directly to the ECU with no connectors in between. I think all of them go through the grommet in the firewall in the stock setup.

[THAWA]

Hmm, I'll have to do some researching on the wiring. What is SMJ? Does that mean the NA ECU connector is missing wires?

[vrg3]

The SMJ is the Super Multiple Junction. The giant rectangular gray multi-pin connectors held together with bolts under the dash.

The NA ECU connector is indeed "missing" some contacts and wires. It's fairly straightforward to add more wires and contacts though. You just have to pull some out of another car's harness.

[THAWA]

Okay, I was looking at the 1992 FSM. The wiring between the turbo and the NA models looks to be almost the same except for some things.

First I noticed in the wiring for the throttle sensor the wires are listed as Br, R, B, W for 1-4 on the NA and Br, R, W, B for 1-4 on the turbo. Following the wiring back to the ecu they both end up at Br, R, W, B for A6, B3, B2, B1 respectively. The thing is on the turbo wiring it switches right where I eblieve the three large connectors are right behind the battery to Br, R, B, W. Does this sound like a mistake in the FSM? I can't see subaru switching the wiring on two wires like that.

Next, I noticed the Turbo ignitor has 6 wires leading to it, but the NA ignitor has 5 wires leading to it. The wire it is missing, YR goes to circled Letter C. For the turbo however it has that wire coming from a circled letter F. What is that about?

I think there was something else but I can't remember.

[vrg3]

Yeah, I think the wire colors for turbo models are incorrectly stated. I think you're right.

That extra wire for the ignitor supplies +12v. Apparently Hitachi harnesses supply that +12v while JECS ones don't. I don't think any of the ignitors actually use it though.

[Legacy777]

Question......do you have to use the hitachi ignitor, or can I use the JECS ignitor that's currently on the car?

[vrg3]

You can use your stock ignitor.

[THAWA]

Well my stock ignitor is a Hitachi one anyway.

She lives!

I started her up and it revved to about 4k rpms, then i remembered I forgot to fill up the coolant so I shut her down again but it seemed to fire okay. I'm sure it threw like 15 codes since I messed up the knock sensor wire, and didnt wire in the map, baro, or solenoid

For the record, the only wires I changed were the crank/cam ones.

[THAWA]

Okay, I decided to do things the crazy way and pull the individual wires from the turbo wiring and just use the connectors that way. Well It turns out that the pressure exchange solenoid and the wastegate control both get wired into the ignition relay. Since I didnt feel like changing out the other wiring that goes to the fuel pump and fuse box and whatever else I just cut the two YR wires(one goes tot he pressure exchange, the other to the wastegate. So now I'm not sure where I can easily tap these wires to. I was thinking I'll just go back to the ignition relay, but are there any other easily accessible wires I could theoretcially tap those two into? It seems to me that any +12v wire should do the trick but I'd like to know for sure before hand.

[vrg3]

You could tap into the IAC valve or the ignition coil pack. The danger is that you'd ask too much of the wiring since you're adding two solenoids to it. It'd probably work though.

Another option is to add a relay there with the coil triggered by +12v from the IAC valve, coil pack, or MAF sensor. That relay could switch power straight from the alternator or battery.

[THAWA]

eh, I think I'll just tap into the ignition relay. Also, is there any reason the pressure exchange and wastegate go through the SMJ instead of going straight to the ECU?

[vrg3]

I don't see any reason they need to. They just do in stock form.

[Project_Legacy]

so i can run those three sensors directly to the ECU? i will try that. and those are the only turbo specific sensors/solenoids that i need to worry about right? besides switching the crank/cam sensor wires? thanks guys.


Don

[Binford]

I've got some questions on the MAP wiring. Can I just tap the power supply onto the the same ign. source as the two solenoids? I plan to relay off the coil or MAF. And then ground the MAP anywhere, or does it have to go back to the ecu?

[Project_Legacy]

when i did my swap, i believe i went off of different sources, because i didnt want to overload or anything (if that is even possible).

for the MAP ground, i think i ran it to the ECU. i sold the car and lost my notes a little while back.