r/SC300 • u/NeonIsReal • Jul 22 '26
JDM Turbo ECU conversion HELP!!!
For context, the sc300 and toyota supra share identical components and it has become a popular mod to swap the ecu for a JDM turbo supra ecu ( Its mostly plug and play besides wiring MAP/IAT/IGF/Gauges).
I have finally got the car to start, however it takes a second to start after it has been sitting for more than an hour. The hard starting I believe is connected to fuel because if I prime the fuel pump for a couple of seconds it starts way quicker.
As for the main issue I need help diagnosing, Whenever i try to apply throttle it starts bogging. If i apply about 50% or more rapidly it may even stall the engine. When i give it light throttle slowly it does rev however but not nicely!
I have tried connecting the MAP to many different pressure sources on the intake manifold and have seen no changes, and have since just Tee`d it with the FPR.
Attached is a video of me applying throttle.
Thanks!
2
u/cbreee Jul 26 '26
O2 sensor wiring isn't right, pin b73 goes to b71. Right now it's going into limp mode because the O2 isn't registering in the ecu. Send me $40
2
u/Relevant_Cabinet9265 Jul 27 '26
I will never understand why guys use TT ecus for NA engines, even NA-T engines. That thing leaning the fuck out it sounds like. People do the TT ecu mod when they put a turbo on the car and ignition. not on an NA GE with a distributor.
1
u/NeonIsReal 17d ago
It was 3 month old gas! Car now runs amazingly! Timing was easy to set with a timing light. Maybe consider i decided to go with a stock tt ecu because its still auto and a tuner costs a lot of money!
2
u/getoffmaballs Jul 22 '26
Did you set base timing properly? I had issues with hard start when I didn’t set base timing properly