Hondata

If they are not hooked up then you should not have them enabled.

Ok I can disable it, it shouldn't have any bearing on my issues though right?

Remove the settings for them from the calibration and see if it works as it should first.

Sure, I've done that and no difference.

Funny enough, in my attempt to upload the updated calibration, it corrupted the where it would rev-limit at any minor load, and after a minute it wouldn't tolerate any load, I had to drift to a stop on the side of the road.

It was fine after a restart and re-upload, but it was bizarre. I captured a datalog too, if that will help.

Did you ever try the s300 in a known working ECU?

I haven't swapped ECUs yet. That's the next thing I'll do, if it doesn't help at least I'd have a spare ECU.

You can also try to find someone else using an s300 and swap your s300 into their ECU.

I finally got around to trying another ECU, it looks like it cleared up the datalogging issues, and I haven't encountered the rev-limit issue yet.

The narrowband O2 though is still reading 3.8V on both ECUs though, I'd like to get that working.

The O2 wire reads .5V at idle if I use a multimeter on it, and Hondata shows 3.8V regardless of whether the sensor is hooked up or not.

I also notice that at power on, it starts at 3V, drops to 2.6V and then ramps up to 3.8V and stays there in about 10 seconds.

What can I do to get my S300 looked at? I don't think its the ECU or sensor causing this, since it happens with no sensor hooked up, and on 2 different ECUs.

Thanks

You need to post the calibration that the datalog is made with as it does appear to be reading AF, but now knowing how it is setup, it's hard to interpret

So I've played around with it some more, I've enabled/disabled open loop a few times. The O2 (Primary Oxygen Sensor Voltage) now reads around 2 volts, and it seems to fluctuate between 0V and 2V, which I guess is better than being stuck at 3.8V; This is with Closed loop set to "Closed loop - stock sensor (narrowband)" and the O2 heater enabled since I have a 4 wire sensor hooked up.

I was curious and checked the voltage at the O2 signal wire and found that when I'm checking the voltage with a multimeter, it drops down to .5V at the multimeter, but it also drops to .5V at the Hondata Sensor monitor. This occurs regardless of which ground I check it with, be it chassis or sensor ground at the ECU. The grounds seem fine. This also occurs with the sensor unplugged by unplugging the subharness that the O2/VTEC come in through.

The rev limit issue shortly after startup cropped up one time on the new ECU so that is still happening.

Attached is the current calibration and a datalog showing what the O2 voltage fluctuations look like.

Do you have a wideband and if so what wideband are you using?

I have a PLX SM-AFR hooked up to D10/ELD, for monitoring purposes. I want to use the stock narrowband for closed-loop.

kraquepype wrote: Fri Mar 25, 2022 6:59 pm I have a PLX SM-AFR hooked up to D10/ELD, for monitoring purposes. I want to use the stock narrowband for closed-loop.

Why? This makes totally no sense. The S300 can use the wideband signal from the PLX to run in closed loop.

Here - try this tune - I made a few small edits:
Changed your closed loop to wideband input / voltage target.
Changed max map for closed loop from 9.2 to 9.3 inches
Changed max engine speed for closed loop to 4812 RPM
Changed your rate of change parameters to what mine are (thanks to user TTR for giving me these)
Changed your voltage/lambda conversion table to remove the middle value you had in there

Try this and see if it works.

It makes sense to me, in that it simplifies the closed loop system and I can continue to use the wideband for monitoring/tuning.

There are 2 reasons I want to use the stock sensor:

1) The SM-AFR has been unreliable for me - it has been very touchy and the DM-6 display for it has failed twice. With it wired up the way it is, it has been working well enough but I don't want to rely on it.
2) Related to #1, S300 does not handle failure of the wideband sensor well when it is used for closed loop operation, at least in my experience. Soon after my engine swap I had it setup to use the PLX wideband for closed loop, but on the way back home from work, my wideband begun reading extremely rich, over 10:1 AFR. I had to pull over and troubleshoot, and luckily I had my laptop and was able to figure out that the wideband signal was missing, so I disabled closed loop and got home. Found later that the wire came loose.

After that, I didn't want to worry about relying on the PLX and I wired up a 4 wire stock type sensor and it worked as expected, up until a few months ago. That's when the unexplained rev-limit, weird datalogging, and wacky O2 voltages started.

Regardless, whether my intent makes sense to me or anyone else doesn't matter, the issue is that my S300 is behaving incorrectly and I want to correct it.

Thanks for the feedback, and the tuning recommendations - they should apply regardless of the sensor used right? (aside from the input and lambda table)

My next steps are to go through my wire harness, and go back to a single wire O2 sensor in case there's something wrong with how the 4 wire sensor is hooked up.

kraquepype wrote: Tue Apr 05, 2022 11:12 am Thanks for the feedback, and the tuning recommendations - they should apply regardless of the sensor used right?

Correct. The rate of change parameters should make the most noticeable difference.