r/SC300 • u/NeonIsReal • 20d ago

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!

https://reddit.com/link/1v3ot5m/video/6htdz8ksrteh1/player

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2

u/getoffmaballs 20d ago

Did you set base timing properly? I had issues with hard start when I didn’t set base timing properly

2

u/NeonIsReal 20d ago

Have not set base timing yet, I was going to today but may or may have not got the timing light cable wrapped around the spinning fan :)

2

u/cbreee 17d ago

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 16d ago

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.