Confused with engine swap wiring, your suggestions please (4 kinda big pics)

[Dr Tweak]

Hey everyone,

I'm in the middle of an engine swap right now and I'm getting kind of confused. I understand that I need to strip out all of the engine related stuff from the recipient car's harness, which I've mostly done. All of the wires that ran from the ecu down the harness I've pulled/cut out. The thing is, a lot of wires ran from some of the body plugs to the ecu, and I cut those. Here is what's left of the harness at the interior end, you can see these 5 plugs that go into the locations in pic 2.

PIC 1


And this is where those 5 plugs go:

PIC 2


Now, here's the engine bay end of the harness, which shows the plugs that go to the fusebox, the positive battery cable, etc.

PIC 3


Here is the new engine's harness at the ECU end, I have not stripped anything out of this yet. You can see the two plugs on the left have been cut, all of these wires went into the dash on the donor car. The two plugs on the right go down the wiring harness, and there's another plug off to the right that plugs under the dash.

PIC 4


Now, am I right in thinking that I have to find homes for all of the wires in PIC 4 on the left that have been cut? Will those wires go to the wires that I see in PIC 1? And how do I go about putting these harnesses together?

I'm getting kinda confused here, thanks a lot for the help

[88 LE]

Now, am I right in thinking that I have to find homes for all of the wires in PIC 4 on the left that have been cut? And how do I go about putting these harnesses together?

You'll have to figure out what each one of the wires do and go from there.

I hope you have an electrical manual for both cars, cos you'll need it.

Why did you cut the wiring harness? Should of left it all intact till you figure out what needs to be rewired. And what goes where.

Good luck with the wiring.

[Dr Tweak]

Yes I do have both wiring diagrams. Are all of those wires coming from the two plugs on the left going to have to find a home in the car? Or will there be some left over? What about in the car, pics 1 and 2, are all those wires coming from the plugs going to have to find homes going to the ECU?

[88 LE]

Originally Posted by JDLangevin

Yes I do have both wiring diagrams. Are all of those wires coming from the two plugs on the left going to have to find a home in the car? Or will there be some left over?

You might have some left over wires, depending on what that wire does.

For example: The donor car might have something that the recipient car doesn't have. And vise versa.

What about in the car, pics 1 and 2, are all those wires coming from the plugs going to have to find homes going to the ECU?

It might goto the ecu, dash, or the engine bay. Thats what your wiring diagrams are for.


What you should of done was kept both engine wiring harnesses intact. Use the harness for the new engine (donor car) and rewire whats necessary (fuse box and the interior wiring).

Well too late now since you cut the harnesses. But it sounds like you got it figured out, just need to find out where the wires go.

[TekPhobia]

Originally Posted by JDLangevin

Yes I do have both wiring diagrams. Are all of those wires coming from the two plugs on the left going to have to find a home in the car? Or will there be some left over? What about in the car, pics 1 and 2, are all those wires coming from the plugs going to have to find homes going to the ECU?

The best thing to do is label everything. The in car plugs go to various items, mostly the inst. panel. There are the idle up diodes, A/C switch, etc. Most everything else goes to the ECU.

Looking at your ECU plugs, the ones on the right should be going to the motor for sensors, alt, etc. What happened?

-Tim

[Mikey21]

One wire at a time and alot of Patience.

[zoni]

doesnt look like toyota... what is it???
why the fuck would you cut all those wires instead of leaving the whole harness intact... sheeeesh... i dunno man... thats a big load of shit, all you can do is do it one wire at a time... i hope you have some wiring skills with those diagrams and a multimeter.

[Dr Tweak]

I didn't cut the harnesses.

The pic your looking at is the harness from the donor car. All of those wires that are cut came out of the dash and plugged right into the computer. There would have been no way to get all those wires without cutting them. I haven't seen this before, most cars have wires that run from the ECU to plugs nearby in the dash.

What I do regret is cutting some of the wires from the recipient's engine harness as I was stripping out everything. I'm pretty much all set now, after I spent the morning labelling everything I have a much better idea of what to do. Thanks for the help.