Hello folks
I could need your help with a question I have: I would like to know if there is any difference from a 1991 VR4 ecu and an ecu from an 1994 VR 4, or are all the VR 4 ecu´s the same?? I was thinking of getting an extra one, but would like to know if I have to get a 1991 one for my 1991 car
I don’t know exact details about which years are compatible, but I can say with certainty that there are differences and incompatibilities across the years.
I know for sure that there is a boundary of incompatibility between 92 and 93 due to the updated engine with differences in camshaft/crankshaft position sensors, so a 93+ ECU is definitely not compatible with your 91.
Here’s a website with details about ECU part numbers for different build date ranges, but it seems focused on US models of the car: ECU Part Numbers...JOHN MONNIN'S PERSONAL 3000GT/STEALTH FAQ
Other markets may have different ECU part numbers and different build date ranges. And just because the part number changed between model years doesn’t necessarily mean they are incompatible.
But based on the fact that 91 and 92 model years in the US used the same exact ECU part number, it may be fairly safe to assume that a 92 ECU will work in your 91.
I just saw this on the site I linked to in my previous reply:
You do not have to install the exact same ECU part number in your car BUT you do have to install a new ECU
with the same E2T number!
Pull out the ECU and under the part number on the label there will be a number starting with E2T.
Those numbers on your original ECU have to match your new ECU.
UP is right on about there incompatibilities between years and sometimes even between Fed /Cali /Jap versions between the years. Remember to not only look at the part numbers from the ecu, but your vin and that plate that’s in the engine compartment. Have owned my 92 since 2014 and only LAST MONTH discovered it was a Cali car and not Fed as I was lead to believe because I never looked at the plate in the engine compartment to confirm what model it was. Back in 2015 I got a Jester ecu from Chromedecu. Here is a link about the various versions of eco they describe - http://chromedecu.org/?product=jester-flash-ecu. Luckily for my 92, whether it was a Fed or Calif didn’t matter - but for other years it can. Unless you had that car since day 1, you need to question and confirm everything about your car or you will be wasting time, money and patience. People do strange “modifications” to their cars and by the time you get it - who knows what was there originally.
Some really interesting answers here 
Thank you very much folks
Fan control is done by the ECU in later models, whereas earlier models use temp sensors in the radiator. There are also likely differences between JDM GTO and Euro 3000GT and USDM 3000GT too, related to emissions control and O2 sensor inputs.
auch… That means having a JDM GTO can possibly create a bit more challange to get parts unless you know japanese.
Actually I think it will be more difficult obtaining parts for UK/Euro specification 3000GT than either JDM GTO or USDM 3000GT because so much fewer were sold.