i have just finished building one of my supra's and have come across this problem..
i have a UK spec engine wiring loom and also a UK spec ECU running a j-spec TT engine.
when i first put it all together in the car, i couldnt get it started, then i borrowed a UK resister pack for the injectors and connected that to the loom, and the car fired up, but it doesnt idle well, feels like its missing. Also have black smoke coming out the exhaust. i've checked all the plugs/coil packs and injectors, and everything seems to be working as they should. when i took this engine out of the car it was originally in, it ran perfect, no smoke, no missing..So i can only imagine its something to do with the loom?? or maybe its because UK's have 550 injectors and j-specs have 440's??
any advice would be appeciated
thanks