For light duty, yes, computers started to hit the road in 1994 models with fully controlled the engines. For Ford this was called EEC-V Diesel Powertrain Control (DPC) V1. These controlled the Navistar (international) 7.3L engine. This era was my specialty. Ford started testing and writing firmware dating back to 1980 but it didn't hit the road till 94. 

Chrysler followed in 95 for common rail Cummins engines, GM followed in 2002. 

Volkswagon ran mechanically injected to 2004 iirc for passenger cars here in the US.