i could be wrong but leave the van wiring as it is, long off the efi loom and only use the rs1800 loom to run the engine, only thing ul need to splice into is the ignition wiring on the standard loom on the column, wire the bay up with the zetec loom.

as i say i might be miles off but im doin a mk3 escort zetec and i have only bought a mk5 escort loom to run it