Hondata

I posted a while ago about how my car was running lean in the morning and rich in the evening during my 45 minute commute to work (basically 20-ish minutes of cruising at 65). For a while I thought it was just something inconsistent about running an AFM tune, so I switched to MAP and dialed in the numbers for about a week.

Seems like, no matter what I do, it's near-perfect on the way to work, and over 5% rich on the way home, even when I try to bump down the values to split the difference.

I would definitely appreciate someone with a little more experience taking a look at what's going on and letting me know if I'm missing something obvious. I turned off the LTFT for a few drives to see if it was skewing the results, but doesn't seem to be.

Look at the difference in your battery voltages. That is the only thing I can see different. This probably has to do with your headlights being on. Those minor differences in short term fuel trim are normal for the day to day operation of the car and not something to be overly concerned about.

Yeah, 5% isn't huge, but it seems weird that running the alternator uses that much more fuel.

I'm not terribly concerned with the highway trims being off, but the lower cam cells showed some crazier things like +3% to work and -12% on the way home. Some of them are over 15% difference in one direction. It seems like it shouldn't vary more than 10% at the worst, and 3-5 would be pretty acceptable.

Return the ECU to stock and datalog and see if the same thing happens.