Volvo: volvo 850 engine swap, ecu computer, computer modules

Question
I put a non turbo 20 valve 850 engine out of a 1997 sedan (automatic) into a 1994 850 non turbo automatic wagon. I left the original wiring and changed some sensors. Do I have to switch the ecu computer modules to get this to work? There are three modules in the 1994 and two in the 1997.

Answer
D'Arcy,
With the original wires left in the car use the original control units and the sensors as not to confuse the control units. That is also all the original injectors and other sensors unless you see numbering on each that is the same. The 94 uses LH 3.2 and the 97 uses Motronic 4.3 or 4.4, as fuel system types. Both very different and parts not always the same.