OK, I gave up on the auto harness I was sorting out for my EJ-into-EA swap.

I'm going to the parts yard tomorrow and hopefully grabbing an intact ECU/harness from a manual car I saw there.

 

question: do i need to grab the wiring *on the engine* or is the engine wiring the same between the AT and manual cars? I'm hoping I can just disconnect the three gray plugs from the engine harness and save the time and effort of grabbing an engine harness I don't need.

 

BTW my donor engine is a 1990 and I can grab the ECU/harness from any Legacy with the same body style, right? (up to 94?)

 

thanks!

The engine harness should be the same, as long as the connectors are the same. I swapped out a 92-93 and had to change out the engine harness. The ECU and Harness also ties into the Dash Harness, which is different between the auto and manual. Both are a paint tu pull. The main harness from the ecu to engine also has all of the lights.... for the front of the car. The fender has to be pulled to get it out of the car.

 

What problems are you having with the current harness?

Later, Larry

this harness is from an auto and it has a TON of extra crap on it that i don't want to sort out or have to make space for under my car's dash. thanks for the answer!

There are some differences. The 90-91 legacies had different sensors for the AT & MT cars. The MAF, IAC, fuel injectors, coil pack, ignitor, and possibly a few other things were different. However, out of that bunch, I think the IAC valve is the only one that could have a different connector....I'm not positive.

 

In 92-94, the AT & MT's had all the same sensors as the 90-91 AT's. However the engine wiring harness went from a 3 plug setup in 90-91 to a 2 plug setup in the 92-94 models.

 

So depending on what year the donor is, and whether it is AT or MT will determine whether you'll need to grab another engine harness to match it.

that's great, thanks Josh. I have FSM #6 for the 1990 Legacy so hopefully I'll find a car that likes the diagrams I already have

 

????.....

so if i get a 90-91 MT harness, should I grab the IAC (wiring diagram says "bypass air control") off of the motor to match? or should I grab ALL the sensors and injectors, as they're different? (what's the MT/AT difference anyway?)

 

 

If it's a 92-94 I will grab the engine sensors regardless.

 

thanks again!

I checked and the connector is the same. Pin 2 of the automatic (AT) connector of the IAC valve has 12v going to it from the ignition relay. Pins 1 & 3 go to the same spots on the ECU.

 

The thing with the sensors.....You'll want to grab the appropriate sensors for whatever ECU you grab. JECS or Hitachi. That is going to determine what sensors you need. Injectors & MAF sensor are the biggies that need to match with the ECU, the other sensors can sort of be fudged, depending on the wiring of the AT/MT identifier pin on the ECU.

 

Let me know if you have any more questions or if I didn't answer your current ones.

How much more is tied into the ECU harness on an auto? I was figuring that the TCU-ECU connector would be one bundle that could be dissconected? How do you rig the VSS when switching an EJ22 into an earlier car? Do the manuals have a VSS, or does it get cut out of the picture when the jumper in the ECU is switched to manual tranny mode? I ask because a 2wd auto is in the woods and available for parts, but I have a nicer AWD manual, all 92's, that I would prefer not to strip, but would if the auto harness is going to be too much of a paine.

thanks Josh. I'll make sure I know what kind of ECU/sensors my donor parts use.

How much more is tied into the ECU harness on an auto? I was figuring that the TCU-ECU connector would be one bundle that could be dissconected? How do you rig the VSS when switching an EJ22 into an earlier car? Do the manuals have a VSS, or does it get cut out of the picture when the jumper in the ECU is switched to manual tranny mode? I ask because a 2wd auto is in the woods and available for parts, but I have a nicer AWD manual, all 92's, that I would prefer not to strip, but would if the auto harness is going to be too much of a paine.

 

You're not going to be able to disconnect the TCU connector from the wiring bundle easily. I'm sure there are some wires that are tied together. You could always cut the connector off, but really it's not that big a deal to just leave it.

 

The 90-94 legacies use a mechanically driven gear in the tranny/diff that drives the VSS in the combination meter (gauge cluster). So it shouldn't be a big deal when converting it to an earlier car, since they probably had mechanical speedos as well.

So I will have to figure out some way to incorperate the VSS into my EA82 gauge cluster. It'll get done...someday. Well thanks Josh. Your website helps too.

Yeah....the other thing you can do is mount the newer electronic VSS supposedly on the older transmissions. You could then feed that signal to the ECU, however you're back to square one with reading your speed on the dash.