Hello and please help, 87i engine into 91i

[firstRWD]

Hello r3v! I've been a member of bimmerforums for a while now and since I actually use r3v more when I can't find more in depth things on there, I figured I should just join here.

My problem is this. I just got my new engine today. It's from an 87i. My car is a 91i. What I can't seem to find anywhere is what I'll need to do to the wiring harness to get it to work. I'm using the 87 harness because the oil pressure sensor wire on my 91 is cut anyway and I need to get this car (my only car right now) running this week. The 87 harness is still on the engine, so I just need to hook it up. Thanks in advance for any help you guys can offer.

Jeremy

[jlevie]

I think I said this in your other thread... Using that harness in your car involves modifications to the harness and to the car's wiring. It would be far, far easier to fix the oil pressure wire on the 91 harness. If you don't want to do that, get a harness from a 9/88 or later car.

[s52e30m3]

I think I said this in your other thread... Using that harness in your car involves modifications to the harness and to the car's wiring. It would be far, far easier to fix the oil pressure wire on the 91 harness. If you don't want to do that, get a harness from a 9/88 or later car.

Agreed. It will e far easier to do it this way.

[firstRWD]

I was planning on doing that as you'd said, but then the guy that I got the engine from seemed really sure that it would be more of a pain to swap everything over from one engine to the other and said it would only be a couple wires different on the harness. That's why I asked here. He also said something about the fuel injectors being different somehow, though I couldn't find anything about that so I think he might have been wrong. I'll just see if I can swap the wiring over then and fix the oil pressure sensor wire. Will all of the wires be in the same spot? As in, if I have both engines out and sitting there, can I just pull off the 91 harness and start putting it on the 87 engine, replacing the 87 harness wire for wire and have it all match up? If not, is it easy enough to figure out the differences or should I settle in for some searching tonight? Thanks.

[jlevie]

The engine sensors are the same on both engines, so you can use your 91 harness as is on the 87 engine. When pulling an engine I think it is a lot easier to disconnect the harness from the engine and leave the harness in th car than it is to swap harnesses. Just label each connector as you disconnect it.

[firstRWD]

Ok. I'll give that a go. I just thought it might be more straight forward if I replaced it wire for wire out of the car. I could label everything with masking tape and leave the harness in the car. I'm just a little unsure of the whole thing because the most I've done before is things like starters, alt, brakes, and the usual small stuff. But honestly, the wiring is the only thing that I'm unsure of now that I've looked things over. The mechanics of it all don't seem difficult really, just on a larger scale than I've done before. I'm hoping to get my car back up and running before the end of the week. Thanks for the knowledge of what will work and the guidance of how I should go about it. Hopefully my next post will be that it worked and how excited I am that my first engine swap went down without a problem.