Hi all, in trouble again and need advice. I have a 2009 Ulysses fitted with an APH exhaust and K&N filter which is running lean with an AFV reading of 90. Can't get re-mapped locally so opted for wideband o2 sensor and map from Buelltooth. Tried to fit new sensor but couldn't undo old sensor with a modified 7/8 ring spanner so ordered the 3/8" drive sensor socket. I put the bike back on the road as socket is on backorder but now it won't run right. It starts and idles ok but within a mile its running rough and losing power and then the engine management light comes on and it starts running fine again. Pull it, switch off engine, switch engine back on, management light goes off, ride away and the whole scenario starts again! Fault code reads "13 l Rear O2 always lean" and AFV at 87 but once the engine management light comes on it runs ok.

Is the ECM broken at the grey connector?

Very common on 2008/2009/2010 Ulys.

Results in very low AFVs.

Have you tried riding it standing up? Have you tried moving the ECM?

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08 Specialized Langster

No obvious damage to ECU. I have a bracket supporting the seat base to keep it off the ECU and I checked using bluetac and there's no contact. I tired standing and moving back on the seat but no improvement. AFV is usually at 90 since exhaust fitted but no additional fault code is registering. Since I removed the right side subframe rail to help access to the o2 sensor could it be an issue with the earth? I read somewhere that the ECU and O2 sensor are earthed through the subframe to the earth strap under the mailbox.

I'd go back to the standard map rather than trust the Buelltooth one after all the bad reports I have read about them

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2001 X1 2009 1125CR 2006 Uly X3 2010 Uly a fully Maz'd S1 and a 1991 RS1200 Westwind.

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Mithered ta death.
92 MB
96 S2T
98 S1W
00 M2
01 X1
03 P3
10 CR

(I missed the Buelltooth mess)

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08 Specialized Langster

Sorry for confusion I didn't explain it clearly. I'm still running stock fuel map. Buelltooth map bought but not loaded to ECU. No joy with checking, cleaning, refitting earth connections. If problem turns out to be ECU what's the best option for replacement, eBay, Twin Motorcycles, IDS??

Talk to Maz who can fully bench test it to see if there's an issue with it.

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Try doing this to yer fueller...........

Afraid not Steve, can only bench test DDFI 1 and 2......above is a 3.

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Mithered ta death.
92 MB
96 S2T
98 S1W
00 M2
01 X1
03 P3
10 CR

Amply demonstrating my lack of fuel infection system knowledge. Note to self- Try to stay out of fuel infection threads. My apologies for misunderstanding and misleading the OP.

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Try doing this to yer fueller...........

I'll hedge my bets that a fitting of a replacement O2 sensor will resolve.

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Buell owners should be committed (but not for life)

I think you might find that once EML comes on, the ECU stops reading o2 sensor and adjusting fuel values and uses the fuel maps as is , that were probably designed on the safe side (rich) to keep things cool .

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Buell Ulysses XB12X 06/08

Thanks delw and barney for response. I have a wide-band o2 sensor available which I tried to fit but the stock sensor is seized in place. If it snaps or strips the treads from too much force it looks like an engine out job to replace it! If I disable the closed-loop would this by-pass the 02 sensor and confirm if the sensor is the issue?

when you say a modded spanner ,did you cut it to clear the cable ?
ie cut the into the ring part ?

slightly different maybe , on my X1 I used a standard ring spanner , just unplugged the cable then threaded it through the spanner then a couple of taps with a soft mallet

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Feros Ferio

Ya did the same, disconnected the wire ran it through a ring spanner. The mod was attaching an extension that fitted out the side of the bike to get some leverage.