| You should not use a *stock* 90-93 ECU in 94-95 cars. The 90-93 ECUs are programmed to control AIVs (for emissions) which were removed on the latter cars. Running a *stock* early ECU on a later car will cause the car to have a very rough idle and run extremely rich. There is a solution, have the EPROM of the 90-93 ECU flashed to remove the AIV code (I currently use an upgraded '93 ECU in my '95). You can run the latter ECUs in earlier cars without issue; in fact a few months ago I installed a '95 NA ecu into a '90 NA. He only ran the ECU while his was being sent to JWT for an upgrade but I haven't heard any problems from him. JWT even ships all of their current ECUs (regardless of year) with the AIV code deleted. The '95 ECU is the 16-bit ECU. Most of the '94 model year cars actually got 8-bit ECUs, but still had the AIV code removed (AFAIK, needs to be verified). You cannot use an ECU that came from a manual car in an automatic car. The ECU and auto tranny talk to each other regarding shift points and manual ECUs lack the hardware to do this. You can however use an ECU that came from an auto in a manual car. In fact most of the JSPEC ECUs modified by JUN and MINES that come to the US are for auto trans, and many people use them in manuals. [I don't recommend you buy one of these, because the JUN and MINES programs have very very aggressive timing, and unless you run high octane gas they will cause detonation; but you can change the JSPEC ECU EPROM to a US EPROM] You cannot use an ECU that came from a CA Emissions vehicle in a federal emissions car. The CA ECU will look for an EGT sensor that the federal car doesn't have and will throw codes (the car will run however). You can however use a federal ECU on a California emmissions car, the federal ECU just ignores the EGT sensor on the CA car. You also can't use a CA ECU on a JSPEC engine, but the Federal ECU should be ok. The 1996 ECU is entirely different from ECUs of prior years. They switched to OBDII and the ECU changed dramatically internally, and the connector on the harness is also very different. I haven't dealt much with the '96 ECUs, they are still very much a black box to me. Also, the NA and TT ECUs are different, but the differences are very subtle. The fuel pump circuitry and the electric fan control are different (in addition to the EPROM of course). Several people have used the NA ECU in a TT by changind the EPROM to a TT EPROM, but personally I wouldn't advise it. I had an NA ECU with TT EPROM in my car for a few miles and the fuel pump made a loud buzzing sound. If anyone knows any of this to be wrong, please correct me. [TT_er, this is basically the same info I sent in my last email - I just want to hear others thoughts on it]
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11:50:48 03/10/04
For reference, my understanding of the Z32 ECU: - 
