Reply With QuoteOn the superdukes we were disabling the o2 sensors and only using pressure sensors. You can do the same with the Buell ecm I believe.
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...
On the superdukes we were disabling the o2 sensors and only using pressure sensors. You can do the same with the Buell ecm I believe.
i did read about adding a pressure sensor (MAP). Maybe this is what I need to do...
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?
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_ad...y.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.
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-Foru...egalog-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 :-)
Thanks for the help....I'll see what I can figure out...
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