maybe there is a date on the ecu,s.that will tell you pre s2,,s2 can run an s1 ecu,,there is no knock sensor on the 1 ecu,so the s1 cant run an s2 ecu,coz this has said sensor,,(so i have been informed),,something to do with the extra spade end fittings in the connectors too,,my 88 s2 has squares,,blue red and white,,i also have a standard 90 spec ecu spades and diamonds,,my squares one is possibly a chipped s1 ecu,,if this is of any help dating your box(arf,arf),,standard ecus go for a tenner on ebay,chipped ones are a lot more,,ford parts dept can tell you the history of your ecu if your desperate,,take it in to them they should be able to punch in the chasis no to date the item.hope this helps,
dont know if they charge for this though,,,,?
