Will there be any bad effects if I disable the O2 sensor on my bike using ecmspy? I burned the race maps to my ecm recently, a few hundred miles ago, and it ran perfect, better than ever, but now it seems to slowly be returning to how it was with a slight stumble, and I am thinking that it is leaning out automatically. I haven't checked the AFV value yet which I think is what I need to do... any thoughts?
Ecmspy question: disabling O2 sensor
- Thread starter snrusnak
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Can I reset the AFV value, then ride 20 minutes to let it learn, then go and disable the O2? This should give a pretty good map right? Temp and density changes should still be accounted for via the IAT sensor right? If I'm not mistaken they are adjusted based on intake air temperature. I just need a way to keep the bike from leaning itself out, it runs so much better right after the ecm flash, then leans out over time back near to stock and runs very lean and crappy.
need to do some data logs, figure out what is going on, could be as simple as an intake leak, disabling the O2 sensor is not real smart for any lenght of time, unless you are doing a Dyno tune with wide band O2 sensors to monitor how it's fueling, JMHO, I am by no means an expert on tuning
So do you mean I could dyno tune it with wideband and then not worry about it, or I should set up a gauge on the bike and constantly monitor it? The guy down the street has a shop and said he'd disable the O2 and tune it with a wideband. Don't know what he'd charge as of right now.
Nope, once the mapping is done with the WB O2 sensor, you plug your original narrow band sensor back in, the O2 doesn't just monitor fueling, it can trigger the CEL in case something funny happens, and save it from potentially catastophic damage
yes, it will try to get the A/F to stoich, which is the most efficient, powerful, and reliable, the general issues with the stock ecm's maps is they are tuned with a very broad brush, a dyno tune will get the maps a lot tighter to your specific running conditions, it will still run at stoich, where you want it, but it will get rid of any stumbles in the maps that may be too far apart or just not enough time in to self adjust,
See for whatever reason once it returns the A/F to stoich it is just too lean, the bike runs excessively hot and has terrible transitioning of power smoothly through the rpm's. Then there's the low rpm stumbling. With the race map right after the tune it was running much cooler, more powerful, started better, idled better, and no stumbling. I'd like to adjust the end resulting A/F ratio to richen it up a hair, is there a way to do this?
Hi, Noob to ecm tuning here, but from what I've read so far, the O2 sensor adjusts the AFV measured to the AFV specified in the maps, after applying corrections for IAT, battery voltage etc... So if you had an intake leak it would try to enrich your AFV to acheive stoich. If your bike is leaning out over time then either the AFV in the maps is too lean (not the case here apparently) or the O2 sensor is defective (not putting out correct voltage) or the correction parameters in the ecm are incorrect. I don't know whether these parameters are changed when a race map is flashed to the ecm, or whether only the maps are changed, but they can be anywhere from 5% to 60% change in AFV depending on the parameter. If someone messed with them it could totally throw off your maps over time, especially when starting & idling where most of the enrichments are high...
Just a thought. You can download tuning notes, which might be helpful to you when checking these parameters against stock steeintgs, here:
http://www.ecmspy.com/download/BuellTuningGuide_EN_V2.0.pdf
Good luck
Just a thought. You can download tuning notes, which might be helpful to you when checking these parameters against stock steeintgs, here:
http://www.ecmspy.com/download/BuellTuningGuide_EN_V2.0.pdf
Good luck
I'm going to check what the AFV actually is tonight, and post back. The thing is, I do not believe that they have the bikes tuned to a proper a/f ratio from the factory, I think they tune them lean to pass emissions. So even though I burned the race maps to my ecm, the AFV is adjusting it back to stock. This brings it near to what it was in the first place....I need a way to adjust what the "final" a/f ratio is....what the AFV see's as the correct final a/f ratio...
Hey snrusnak, JMO, but all the O2 sensor does is apply one correction among many to the base fuel map. There is no 'program' or 'base setting' in the O2 sensor, all it does is deliver a voltage depending on engine temp and the oxygen content of the exhaust gas. This voltage is monitored by the ecm and adjustments to the base fuel map injector pulsewidth (more or less gas added to the mix) are made based on this voltage, the target AFV, battery voltage, TPS, IAT etc... so either your O2 sensor is not putting out the correct voltage, your target AFV has been incorrectly reset in the ecm or some other correction parameter has been changed. I would start by checking for induction leaks, then check the correction parameter tables with ecmspy and make sure they are all set to factory default ('cause most people don't have the problems you have running them) and that the AFV is set correctly. If all that is OK, I would check the O2 sensor or replace it. I once had one that only malfunctioned when the ambient temperature exceeded 80F, otherwise it was perfectly good. Or you could add a MAP sensor and retune your maps based on that…
Thanks for the info. There is a chance my intake seals are leaking....I'm replacing them soon. Also, I'm still new to ecmspy so don't know how to do everything you listed lol, but will work on it.
I may be missing something, but here's the way I understand it:
There is a predetermined base a/f ratio, supposedly 14.7 is "perfect", however I have heard the bikes are tuned lean from factory to meet emmisions. So first of all, is this true that there is this base a/f ratio that the ecm(using the O2) always tries to adjust to(I think this is what the AFV is)....? If so then the base a/f ratio might look more like just say 15.5...right? So maybe the race maps also have a different base a/f ratio than the stock ecm?
Before I go onto to anything else, is what I said above correct?
I may be missing something, but here's the way I understand it:
There is a predetermined base a/f ratio, supposedly 14.7 is "perfect", however I have heard the bikes are tuned lean from factory to meet emmisions. So first of all, is this true that there is this base a/f ratio that the ecm(using the O2) always tries to adjust to(I think this is what the AFV is)....? If so then the base a/f ratio might look more like just say 15.5...right? So maybe the race maps also have a different base a/f ratio than the stock ecm?
Before I go onto to anything else, is what I said above correct?
As far as I know, the A/F ratio is specified in the base fuel maps, which are set lean by the factory. To these base fuel maps corrections are applied to compensate for engine temp, engine & sensor wear, battery voltage etc... from the tuning guide I linked to earlier:
5.1.2.5 Exhaust Gas Oxygen Measurement Corrections
The EGO and AFV are corrections which are derived from the measurement of oxygen in the exhaust, using the O2 or Lambda sensor. The corrections are derived and applied to compensate for other uncertainties, such as changes in air pressure, engine to engine variations, air filter clogging, exhaust deterioration, engine deterioration and sensor calibration errors.
The EGO is a correction derived and applied during Closed Loop and Closed Loop Learn control regimes.
The AFV is a correction derived in the Closed Loop Learn (and Open Loop Learn) regime(s) and is applied in the Open Loop and Open Loop WOT control regimes.
For Buell X1, S3 and XB engines before 2010 model year, the O2 sensor is installed into the rear header only, this is the input to the ECM to calculate the EGO correction. Although the front cylinder's mixture is not monitored by the ECM, EGO and AFV corrections are applied to both cylinders in the same manner.
More advanced EFI systems use additional measurements to improve the accuracy of the air flow calculations. For further reading, see reference 9.
Here is a link to a quick start guide by xoptiinside which outlines the basic steps to follow when tuning your ecm: http://xoptiinside.com/yahoo_site_admin/assets/docs/Is_tuning_your_bike_a_little_blurry.24475730.pdf
But first:
set static timing
clean throttle body
set tps
clean plugs
check plug gaps ngk plugs standard plugs
set gap to .035
clean air filter (high flow )
reroute the breather tubes
start tuning now
dont skip the step order
Good luck
5.1.2.5 Exhaust Gas Oxygen Measurement Corrections
The EGO and AFV are corrections which are derived from the measurement of oxygen in the exhaust, using the O2 or Lambda sensor. The corrections are derived and applied to compensate for other uncertainties, such as changes in air pressure, engine to engine variations, air filter clogging, exhaust deterioration, engine deterioration and sensor calibration errors.
The EGO is a correction derived and applied during Closed Loop and Closed Loop Learn control regimes.
The AFV is a correction derived in the Closed Loop Learn (and Open Loop Learn) regime(s) and is applied in the Open Loop and Open Loop WOT control regimes.
For Buell X1, S3 and XB engines before 2010 model year, the O2 sensor is installed into the rear header only, this is the input to the ECM to calculate the EGO correction. Although the front cylinder's mixture is not monitored by the ECM, EGO and AFV corrections are applied to both cylinders in the same manner.
More advanced EFI systems use additional measurements to improve the accuracy of the air flow calculations. For further reading, see reference 9.
Here is a link to a quick start guide by xoptiinside which outlines the basic steps to follow when tuning your ecm: http://xoptiinside.com/yahoo_site_admin/assets/docs/Is_tuning_your_bike_a_little_blurry.24475730.pdf
But first:
set static timing
clean throttle body
set tps
clean plugs
check plug gaps ngk plugs standard plugs
set gap to .035
clean air filter (high flow )
reroute the breather tubes
start tuning now
dont skip the step order
Good luck
Thanks, yeah I have read some and most of what's in that link. I'm not sure, but I sort of disagree with your first sentence, but if someone knows for sure please correct me. I think the maps are not what the sensors adjust to. For example, I flashed the race maps to my ecm, and it is leaning out, so I think it is taking the new richer fuel maps, and leaning them out to get back to the original "base" a/f ratio.
Like I said, I'm not positive that's how it works, but it seems that way... If it is in fact like you said, and the fuel maps are the "base" that everything adjusts to, then why would it be leaning out over time, when starting from the base? It is getting further from the base fuel maps(by applying a AFV less that 100%) in time rather than closer.
Like I said, I'm not positive that's how it works, but it seems that way... If it is in fact like you said, and the fuel maps are the "base" that everything adjusts to, then why would it be leaning out over time, when starting from the base? It is getting further from the base fuel maps(by applying a AFV less that 100%) in time rather than closer.
I checked the AFV this morning it was 94.9 then rode some and it rode pretty good but not as good as right after I burned the race maps to the ecm hundreds of miles ago... That AFV doesn't seem too far off but still is leaning it out.
Hey snrusnak I found this sticky thread on the forum which might help:
http://www.buellxb.com/Buell-XB-Forum/Do-It-Yourself-Buell-Mods/ECMspy-megalog-tunning
It sounds to me as though it may be leaning out because the settings have been messed with in the ecm (if they are not reset when you burn a race map to it) or your O2 volts are off (not enough or too much).
I'm definitely no expert though, so maybe one of them can chime in and set us straight
http://www.buellxb.com/Buell-XB-Forum/Do-It-Yourself-Buell-Mods/ECMspy-megalog-tunning
It sounds to me as though it may be leaning out because the settings have been messed with in the ecm (if they are not reset when you burn a race map to it) or your O2 volts are off (not enough or too much).
I'm definitely no expert though, so maybe one of them can chime in and set us straight
