RomRaider

After years of running merpmod SD and less than desirable injectors for idle on E85(Five-O 1300cc side feeds, then Five-O 1600cc top feeds) I switched to FIC 1650CC top feed injectors. The car idles decently (still get hiccups coming to a stop but it doesn't die), I set up the parameters according to their recommendations. But for the love of god I cannot get the idle to stabilize at stoich. This is an '05 STi with an 04 ECU A2ZJ710J merp gratis.

I have so far played with extremes with:

Engine load smoothing factors
VE
Low pulse width compensation
Primary Open loop (also tried forcing OL)
Closed loop fueling targets (ECT/Load)
Latency
Per injector primary fuel offset
Set a high idle
Set avcs to open a low/idle conditions

Even though the car runs relatively well under all other circumstances, when it sits at idle it will start out at stoich and then hunts it's way by to 12.5:1 afr EVERY time after it warms up no matter what the condition. This makes me feel it's not the injectors or the O2 sensor as it CAN run and idle at 14.7, but makes it's way back to 12.5. Sometimes it will sit at an even richer reading, and leaner but you can see it hunting to find that average and I cannot figure out what it enriching it, if that be the case.

Any personal experience, input, or recommendation on logging parameters are appreciated

Update for posterity - Lowering the Low Pulse Width compensation (IPW) from the recommended 1.148 to 1.000 seems to have done the trick for whatever sense that makes. Still testing as I had changed a couple things together but this has the most response, removing the rich idle.