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Buell Forum » Big, Bad & Dirty (Buell XB12X Ulysses Adventure Board) » Refresh my memory about ECU learning mode « Previous Next »

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Tempest766
Posted on Monday, July 30, 2018 - 04:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

First off...this is specific to the DDFI-3 ECU on the 2008 XT. Don't know or care about previous years, so unless you have experience with the DFFI-3, please don't speculate.

Does the ECU go through AFV learning process every time you do a TPS reset?

Is this also true for the IDS racing ECU?

TIA!
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Froggy
Posted on Monday, July 30, 2018 - 05:02 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

TPS and AFV are unrelated functions, so resetting one has no bearing on the other.

The AFV learning happens every time your bike goes into closed loop mode, which is basically every time you are just cruising.

That is also true for IDS/EBR ECMs.
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Shoggin
Posted on Monday, July 30, 2018 - 07:24 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

+1 Froggy is right (as usual: ))

Note that the AFV adjustment % you see in ECM parameters is a global adjustment for closed loop operation. It is the EGO correction that adjusts the open loop map. So it depends where you need to look if you're having issues.
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Ourdee
Posted on Monday, July 30, 2018 - 09:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Just cruising at over 3500 RPM. Not lugging at under 2500 RPM.
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Tempest766
Posted on Monday, July 30, 2018 - 10:56 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Thanks. I thought the ECU learning mode was triggered by a TPS reset or loss of battery power.

so what if you're never cruising, but constantly on and off of the throttle through local twisties? Some nice hilly twisty back roads around here where I'm usually in 3rd or 4th gear at anywhere from 40 to 70mph. I also read in a tech brief that the ECU goes into open-loop when above 50ish MPH. My cruising is usually faster than that? how long, and under what conditions for it to learn and adjust?


(Message edited by tempest766 on July 30, 2018)
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Tempest766
Posted on Monday, July 30, 2018 - 11:04 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

@Ourdee - I don't get the relevance of the RPMs here. My typical operating range is 2800 to 4200 RPMS, but closer to 3200, as running the thing at high RPMs constantly causes me excessive oil loss.
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Shoggin
Posted on Tuesday, July 31, 2018 - 12:29 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Why so concerned about learning mode? Does it run poorly?


Is the oil coming from the top of the crankcase, like under the starter and down the side? Non-OE starters had a un-sealed bearing in the nose cone letting a lot of primary oil to splash out through the starter body during high RPM. You can either get a Buell/HD nose cone ($80-ish) or a whole new OE starter.
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Shoggin
Posted on Tuesday, July 31, 2018 - 12:33 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

To answer your question, the ECM is always 'learning' and drops into CL very quickly. It's not possible for you to ride from your house, do the local twisties, and ride back, without the ECM reading the O2 and adjusting accordingly.

'Learning Mode' just means it is allowed to make bigger changes/faster. Totally unnecessary if your bike runs OK.
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Ourdee
Posted on Tuesday, July 31, 2018 - 02:01 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

So, Froggy answered the questions asked in the first post.

The relevance of the RPMs has to do with Open Loop and Closed Loop in the ECM. A couple of minutes at 3200 RPM with a light load should put it into closed loop and allow it to learn based on the O2 sensor readings.

I have some historical reference material from Harley Davidson revised in 2001. This may give you an idea of what is going on in your ECM. http://buelltuning.free.fr/injang.htm#a1
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Screamer
Posted on Wednesday, August 01, 2018 - 01:07 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

TPS and AFV can have a small impact on each other if either one is a dramatic distance from "normal".
Ourdee is correct in stating that the learning mode is most effective when there is a load. Our team's recommendation for learning a new AFV used to be "4th/40/4". Which meant hot engine, 4th gear, 40 mph, slight uphill grade and slight throttle (to create load) for 4 minutes.
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Tempest766
Posted on Wednesday, August 01, 2018 - 02:32 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Quick followup on this. Found the document I was looking for on my computer that goes into detail about how the ECU adjusts mixture and timing: ECM tuning notes for Buell DDFI and DDFI-2 (2nd edition). This document seems to give very specific and authoritative information about the injection process, which is what I was looking for.
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Smorris
Posted on Sunday, August 05, 2018 - 03:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

so , are you going to share that document?
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Tempest766
Posted on Tuesday, August 07, 2018 - 08:47 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I dunno. What are the legalities/ettiquite? Some forums frown on sharing pilfered documents. I suppose if a moderator tells me it's OK.
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