This started out as a cry for help, but now I'll just let it be a DIY/Technical thread/FAQ/etc., to help people who attempt this in the future. My car still doesn't run yet (probably for reasons other than the wiring harness at this point though), but I think this information will be vital to those who potentially will be in my situation, as I couldn't find this information in one place anywhere.
If you have an early model 'i' car, and for whatever reason (say you're retarded like me and crushed your first one) you need another wiring harness, the first thing I'd recommend is that you get a second early 'i' harness (up to 9/87 according to realoem).
If however, for varying reasons you wind up with a 10/87+ wiring harness, which is probably the more common one, you can make it work, but there are definitely some things to consider:
1. You will need BOTH the fuel rail wiring harness and the fuel rail, the inlet/outlet nipples are both on the front of the rail in the later cars, so the fuel injector wiring harness can fit.
2. You will need an O2 sensor from the late model car, or you will need to splice/solder/etc. the appropriate connector onto either the wiring harness or your original O2 sensor. Be comfortable with wiring / soldering, or definitely give up at this point and source the early harness.
3. You will need to do the same thing for the oil check sender, as the connections are different there too.
4. The tachometer/fuel impulse signals on early model 'i's are picked up with C104 (3 plug) at the glovebox, near the ECU. You can ignore the green wire, but you'll need to get those signals to the other two wires some how. It looks like the later 'i' harnesses sent that information directly to C101, so I'm guessing the best approach is to tee into the wiring harness at the glovebox, but I haven't done so yet (nor am I confident which wires to use), any help here would be great, when I find the answer I'll edit this.
5. The starter wires on later model cars has a third smaller wire (I think it's a ground) that goes to the top post on the starter. I'm told you can ignore this, but my starter had a post there (that was never used, it was a refurbished one), so I just attached it there.
And I think that's it for now, hopefully this'll be helpful for the next person in my predicament. I'm off to figure out why the car won't start (I might have lost a transfer pump...)
-Brett
If you have an early model 'i' car, and for whatever reason (say you're retarded like me and crushed your first one) you need another wiring harness, the first thing I'd recommend is that you get a second early 'i' harness (up to 9/87 according to realoem).
If however, for varying reasons you wind up with a 10/87+ wiring harness, which is probably the more common one, you can make it work, but there are definitely some things to consider:
1. You will need BOTH the fuel rail wiring harness and the fuel rail, the inlet/outlet nipples are both on the front of the rail in the later cars, so the fuel injector wiring harness can fit.
2. You will need an O2 sensor from the late model car, or you will need to splice/solder/etc. the appropriate connector onto either the wiring harness or your original O2 sensor. Be comfortable with wiring / soldering, or definitely give up at this point and source the early harness.
3. You will need to do the same thing for the oil check sender, as the connections are different there too.
4. The tachometer/fuel impulse signals on early model 'i's are picked up with C104 (3 plug) at the glovebox, near the ECU. You can ignore the green wire, but you'll need to get those signals to the other two wires some how. It looks like the later 'i' harnesses sent that information directly to C101, so I'm guessing the best approach is to tee into the wiring harness at the glovebox, but I haven't done so yet (nor am I confident which wires to use), any help here would be great, when I find the answer I'll edit this.
5. The starter wires on later model cars has a third smaller wire (I think it's a ground) that goes to the top post on the starter. I'm told you can ignore this, but my starter had a post there (that was never used, it was a refurbished one), so I just attached it there.
And I think that's it for now, hopefully this'll be helpful for the next person in my predicament. I'm off to figure out why the car won't start (I might have lost a transfer pump...)
-Brett
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