RomRaider

Well if someone with the 32bit ecu and who is running the stock fuel map (i.e. nice and rich) can log "A/F current #1", we can see the range of the front o2 (even if it might not be accurate that rich). If you do log, post up a copy of your fuel map and log a/f current #1, rpm, and engine load.

Ill get a snapshot in a few. I was looking at some old logs to see if I ever logged it but I only tried the sensor which bottomed out at 11.02.

Ok here are some logs. It looks like at stoich (14.7) the current is around 0-0.38. When it reads air or basically tops out (20.67), it reads 1.75. When bottoms out at 11.02 it reads -1.38. Here are some various logs while cruising and at WOT.

Your AFR readings actually topped out at 20.79. Your lambda vs. current table appears to be set up such that lambda = 0.750 is the leftmost entry and corresponds to a current of -1.375 and the rightmost entry is lambda = 1.414 and corresponds to a current of 1.750. That's somewhat different than the values in the table posted earlier.



What car is this and which ROM calibration ID?

Well, I installed the LM-1 this past weekend and did some readings against the stock O2. I am getting different AFR readings in CL. RomRaider reports 14.7 from the stock sensor where as LM-1 reads 14.3-14.4. I am not sure how to account for the difference. Jon [in CT] suggested in his previous post that FHI targets 14.5 as stoich. Could that account for the error between the logger and WB? Perhaps the AFR calculation is shifted due to the stoich not being considered 14.7 by the sensor. JUst throwing some ideas out on the table. Please feel free to comment.

Both sensors are actually reporting lambda and both RomRaider and the LM-1 are converting lambda to an AFR using the same multiplier, 14.7.

Well Ziggy, you could log in Lambda to avoid any conversion issues. Do you still have your rear O2 sensor plugged in? What does that say? The LM-1 has been properly calibrated as well?

By rear, do you mean stock rear O2? If so, than no, it is not plugged in. I removed it and put the WB sensor in its place. I defeated the codes so I do not throw a CEL. I will try logging using lambda and see where I am in AFRs on the LM-1 respectively. Good idea.


To follow up on Jon's response:



Jon, so based on what you just said, and what you said here:

"Use 14.5 as the stoichiometric A/F ratio instead of 14.7 and then you'll see what FHI engineers see when they look at that table."

and the graph your posted of the stock O2 sensor current output, I interpet the info as the multiplier for stock sensor is 14.5. Maybe I am missing something here. I guess it is easier to talk in lambda so the conversion issues are eliminated.

If mA is less than -1.30 or greater than 0.74, lambda will still be the same (0.76, 1.38 respectively), due to the fact that there is no interpolation outside the axis range. Also, a/f sensor #1 lambda and current are rounded up when logged through SSM.

Thanks, just saw you posted that info in the other thread, too.


Yeah, you misinterpreted his comment. It only had to do with how much current the O2 sensor moves, nothing to do with what AFR the ECU targets in closed loop. (if I interpreted the discussion on page 2 correctly).

Hmm, the table posted above for the stock O2 scaling with respect to current supports what I just mentioned....at least in my head it does . If you look at the table, current of 0 corresponds to 14.7AFR, lambda of 1, according to RomRaider. The graph that Jon posted suggests that current of 0 is closer to 14.5AFR or so, judging on the scale and where the curve intersects with the X axis. If lambda was 14.7, that line would intersect the X axis closer to 16AFR. My WB readings seem to suggest this as well.

Then how could he log an AFR of 11.02:1 (equals 0.75 lambda) if the ECU is rounding reported lambda up? A different table would explain it.

What type of ECU uses the table posted above?

I see exactly 14.7 @ stoich since free air calibrating my TXS Tuner pro. It very much agrees with the stock 02 sensor. This is the bosch wideband btw.

The only other table is front o2 compensaton based on atmospheric pressure. It is possible the logger is rounding down. SSM adds .5 to the value (post-conversion) and truncates. The table is correct.

That's how you do rounding to the nearest integer. Each unit (integer) sent by SSM for lambda represents .0078125 lambda. So if it's rounding to the nearest integer, then logged lambda will be less than .00390625 different than the internal ECU lambda from which it was derived.

So how can you explain why he was able to log AFR as high as 20.79:1 (1.414 lambda)?

What type of ECU did that table come from?