Replacing wiring on my 1981 spider 124 2000

[Alirkfd]

Guys new with Fiat........
I am replacing engine on the car, but my old wiring is very fragile, my used engine came with the wiring which has all the clips and boots.
here is my question:
New wiring has no marking.
I was planning to cut the wires 8" from the firewall and solder the new wires from the new used engine. When peeled the new wire for soldering there are no marking all white wires and two brown wires.
Please advise.

[Anbele]

You might want to visit this site….
https://www.mirafiori.com/forum/
Here you’ll find wiring diagrams to download. Good luck!

[spider2081]

Fiat made the wire harnesses in sections that plug into each other.
I would look for good used sections of the wire harness that you want to replace. That way there would be no splicing and the colors would be per wire diagrams.

Fiat used white wires with numbers stamped in the wires insulation in their fuel injection engine harness. The numbers stampings were close to the ends of the wires maybe the last 6" to a foot.

I agree join mirafiori.com and access their library. Download and study " Spider 2000 Electrical Diagnostic Manual 1980-1981" It has all the wire diagrams with wire colors and circuit descriptions for your car.