RomRaider

Hello,

I was lucky enough to come I into possession of an 04 STI built in 06 by AndrewTech that sat for many many years with blown out side feed injectors. It had a Turboxs rotated gt3582R kit on it with what appears to just be an 18psi base map on the UTEC. The stock ECU was completely unchanged other than the idle being raised. (The car ran very poorly as you can imagine.)

I've sorted out what's actually in control of what and it seems like the DTEC is indeed controlling boost and the UTEC is modifying the fuel and taking over the timing above 60% throttle. I love the Gameboy.

I've managed to tune a surprising amount of drivability into this setup by fixing some weird timing maps on the UTEC and many changes to the stock ECU tuning. I think the previous owner got into it without knowing what he was doing. It's on the 700 rom currently. I'm pretty happy with it other than one issue. The injectors are what I believe are decapped factory injectors, so around 800cc. The car runs great to around 23psi without knock. The problem is after a week or two it will throw a misfire CEL. From what I've logged it seems to be at idle or transitioning between accel and decel. I think this is due to the injectors being unhappy with low pulsewidths, though it could be the flywheel.

I can't seem to find anywhere to change the misfire threshold or minimum pulsewidth. Raising the idle to 1100 has prevented a lot of the code but it will still randomly throw due to throttle transitions. Any advice would be greatly appreciated. Would going to the 710 map be advantageous? My goal is to keep the car era correct so I don't really want to make changes beyond tuning. I just really want cruise control to work.

Thanks!

For a2zj710j you can find min ipw comp searching on the forum, misfire threshold is at 59e70, with axes 59e08 & 59e38

I think the first thing I need to try is moving everything I've got over to the 710 rom and make sure it all still plays nicely with the UTEC and DTEC. I'm glad the threshold can be changed. The UTEC has its own knock control, even though it's all very rudimentary.

I was able to get the min PW added to the definition, does this look right for the misfire threshold? Is there a reason these haven't been added to the definition files? Am I missing something? I'm using the definitions from this Link.

Thanks for the reply!

[UPDATE: Got everything sorted. The 710 rom seems to have better DBW feel than 700, it could just be in my head. Tried raising the min PW from .57 to .63 and got a smoother idle and no CEL but the car was burning noticeably more fuel. I think in closed loop it was preventing it from leaning out on decel based on the AFR gauge. Figured .57 could just be the resonance frequency for the injectors so I tried .52 and that also seems to be working well! I did that, raised the misfire threshold from 500-1500RPM, and leaned out my cranking fuel tables some. I haven't had the CEL come back after ~300 miles and it's a little happier starting and idling. If there are any more useful tables that can be added for drivability, please lmk!]