SicSE
Veteran CEG'er
I did 3 dyno pulls today and I'm having trouble theorizing the A/F results, so work with me here.
The SE PCM goes stupid-rich somewhere after 5K and I'm trying to theorize what the determining factors are, that tell the PCM, "hey, it's time to go stupid-rich"... because stupid-rich doesn't always happen at the same time. Stupid-rich happened on run 1 at about 5600RPM, then about 5400RPM on run 2, then shortly after 5200 on run 3. I started all my runs with ECT at 201° on it's way up, (meaning the fans kicked off about 4° ago), and an IAT of 80°. The runs were all within 10 minutes of each other, so drastic barometric or humidity changes or anything like that can be ruled out. Nothing that I datalogged looked to be the trigger for stupid-rich.
At the onset of stupid-rich, the datalog shows the fuel enrichment via STFT's, the dyno chart shows the corresponding drop in A/F. Nothing else in the datalog changes much at that point. A degree change in IAT, (90°ish), or ECT, (206°ish), a 1% change in load, (104%), no change in MAFS voltage, (hits about 4.07 volts max), and spark advance holds steady at around 24°.
Anyone with any theories about the PCM's stupid-rich caculation? There is a calculation for everything and I NEED to figure out what all triggers stupid-rich.
The SE PCM goes stupid-rich somewhere after 5K and I'm trying to theorize what the determining factors are, that tell the PCM, "hey, it's time to go stupid-rich"... because stupid-rich doesn't always happen at the same time. Stupid-rich happened on run 1 at about 5600RPM, then about 5400RPM on run 2, then shortly after 5200 on run 3. I started all my runs with ECT at 201° on it's way up, (meaning the fans kicked off about 4° ago), and an IAT of 80°. The runs were all within 10 minutes of each other, so drastic barometric or humidity changes or anything like that can be ruled out. Nothing that I datalogged looked to be the trigger for stupid-rich.
At the onset of stupid-rich, the datalog shows the fuel enrichment via STFT's, the dyno chart shows the corresponding drop in A/F. Nothing else in the datalog changes much at that point. A degree change in IAT, (90°ish), or ECT, (206°ish), a 1% change in load, (104%), no change in MAFS voltage, (hits about 4.07 volts max), and spark advance holds steady at around 24°.
Anyone with any theories about the PCM's stupid-rich caculation? There is a calculation for everything and I NEED to figure out what all triggers stupid-rich.