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Thread: Always lean after tuning

  1. #11
    Senior Member mriulvr's Avatar
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    Yep, I was looking at the log further in MLV and came to similar conclusions. When I got home I checked the LC-2 NB Emulation settings and the voltages were too narrow. I reset them to .1v - 15.2 AFR and .88v - 14.2 AFR, which gave me a 14.7:1 stoich to match my fuel map, and made sure that the advanced settings were set to 1/3 seconds and warm up and error voltages are .49v. Result, no CEL this morning on my commute. I haven't had a chance to look at the log yet.

    I have output 1 running to the ECM and output 2 running to an AFR gauge. What was odd is that the AFR gauge showed values between around 7.5 to 12.5 for the entire ride. That doesn't seem right even with adjustments for the hot ambient temperatures of almost 90 degrees this morning. This and the battery voltage is making me wonder if I have a bad ground somewhere. The battery is only about a year old and I keep it plugged into a tender when parked at home. The LED turn signals I have are some cheap ones and the wires are pretty flimsy and not well connected to the connectors, I have had to redo several of them. I also ran a ground wire from the battery a couple of years ago. Maybe this weekend I will trace the wires and recheck connections. I did notice that when the CEL light was on and I turned the turn signal on that the dash lights faded just a bit as the turn signal light flashed. Shouldn't be doing that.

  2. #12
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    A bad ground is likely, possibly for the ECM. Sounds like you have made progress otherwise!

  3. #13
    Senior Member mriulvr's Avatar
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    So, I do not have the CEL issue but my AFR readings are whacked out. I thought that my AFR gauge might be showing incorrect readings due to a bad ground as they varied between 7 and 10. The gauge is showing readings from the LC-2 Output 2 and the Output 1 is going to the ECM. However the log shows that the AFR values ran between 7.35 and 10.231. I set both outputs on the LC-2 to .1v - 15.2 AFR and .88v - 14.2 AFR. The AFR varied between 80 and 98 during the ride with an ambient temperature of mid to upper 80s. When logging with the WB I was to the point where MLV was only changing fuel map values by 7 or less with most cells only changing by 2 or 3, which I figured was mostly due to differences in temperature, humidity, and ride differences. Overall, they were very stable and the logged AFR values were spot on with the afrBins 2 from my first post.

    I looked at a scatterplot comparing O2 readings and AFR and they are way off from the NB settings. The log shows the following with the NB settings.

    O2 AFR AFR
    Volt logged NB Emulated
    .1 7.64 15.2
    .49 8.78 14.7
    .88 9.52 9.99

    The ECM settings are .56v rich, .49v midpoint, and .42v lean. This doesn't sound like a bad ground to me. I can't figure out why the discrepancy between the LC-2 NB settings and the logged O2 values. My first guess would be to recalibrate the O2 sensor but before I pull it, which is a pain in the butt, I would rather rule out any other issues that might be easier to diagnose and rule out. I will PM the log from this mornings ride if you have time to take a look.

  4. #14
    Senior Member mriulvr's Avatar
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    So I just realized that I had my MLV Calculated Fields set to WB. Switched that off so I don't get the AFR readings. Can MLV be set to show the NB O2/AFR settings?

  5. #15
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    Quote Originally Posted by mriulvr View Post
    So I just realized that I had my MLV Calculated Fields set to WB. Switched that off so I don't get the AFR readings. Can MLV be set to show the NB O2/AFR settings?
    In MLV, you can set the target AFRs to be anything you wish via your MSQ tune file, which of course depends on your tuning goals. There are some stock DDFI-2 MSQ files floating around. There also used to be a program called "XPRFuelMapExtractor.exe" that would take your Tunerpro .xdf and EEPROM .bin and generate a .MSQ for you. It always crashed when I tried to use it, so I generated some by hand. I don't know where the program is, so try some searching.

    This second log looks much better with regard to the O2 IMO. Sensor response looks typical. If you hadn't told me any back story, my only comments would be that you are consistently rich by anywhere from 8-12% in the cruising ranges, per your current stoich setting. I'm not much help on the LC-2 settings other than the bare basics, but there are a few others on the forum with more experience in that area!

  6. #16
    Senior Member mriulvr's Avatar
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    Ended up spending most of the weekend replacing an alternator in my wife's Odyssey, not a fun job. So I did not get to spend time on checking grounds on my Buell. However, I did figure out a couple of things that I had not read, or missed, in all my readings about tuning. First, my LC-2 can be set to emulate a NB O2 sensor but it does not report the AFR as a NB sensor resulting in the wonky AFR readings I was getting on my LC-2 AFR gauge. It only seems to output the O2 voltage as a NB sensor. Second, I had to turn off the open loop learn in my ECM settings. Since my fuel settings in open loop are not set to stoich the ECM was making adjustments to try to compensate for the lean and rich areas that I had tuned for idle, decel, and WOT regions.

    I kept the LC-2 analog out 1, which runs to the ECM, set to emulate NB and analog out 2, which goes to my AFR gauge, set to WB. She is now running MUCH better and the AFR gauge readings are in alignment with my tuned fuel map.

  7. #17
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    That's great!



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