It is largely plug and play for FI wiring. VW built the vehicle harness
such that it could use various engine types without much trouble. There
is only one wire coming to the engine from the front, the black power
wire to the coil from the ignition switch.

You can pull the 2.1 engine and it's FI harness as a unit by unplugging
a few connectors. The green wire from the coil to the tach is the only
one you have to fiddle with and you need to pull the female spade from
the connector or cut it leaving a few inches for splicing.

I wonder about the long coolant pipes since I think the 2.1 setups
expect them to be shorter at the engine end due to the coolant hose
junction assembly they use. You likely need to swap pipes and even front
radiator hoses if the 85 has metal pipes.

You can keep the 85 IC and just use the low pressure oil switch from the
2.1. wired like the 1.9. If you want to use the 2.1 IC you need an extra
step or 2 but not hard to adapt.

Mark

dylan friedman wrote:

> I am contemplating swapping in a fresh 2.1 wbx in place of a failed 1.9 in a 85 GL.
> I have numerous late model 2.1 engine bay harnesses and ecus.
> Is this a plug and play type swap or is the older wiring from the ignition and front of van not capable of the swap?
>
> TIA,
>
> dylan
>