| Author | Message | ||
     Rbuck53 |
Need some insight on this please: This condition is new...just started a couple of days ago: After the engine warms up and the idle has smoothed out to around 1k rpm, when I apply the throttle I get a momentary drop in rpm before the engine catches...then rpm's rise normally with throttle application. The engine starts and runs absolutely perfect in every other circumstance and condition. This abrupt rpm drop has caught me off guard a couple of times whereby actually stalling the engine as the clutch slips into the friction zone. Not fun after sitting at a red light in traffic. 1)The EBR ecm is relatively new and in the relocated position. Plugs are secured. 2)Intake has no air leaks (checked thoroughly). 3)Throttle body and throttle plate are whistle clean. 4)K&N is clean. 5)NGK DCPR9EIX plugs are only 2 months old. 6)TPS has been reset several times to ck effect (no changes result). 7)Fuel cleaner/stabilizer run through 1 tank of gas (no change). Any ideas where to look next? Thanks, Buck | ||
| Rbuck53 |
Last evening: Removed and cleaned the idle motor and cavity. Also checked the clutch adjustment, since there have been several posts about the micro switch on the clutch lever raising the idle when the clutch is beginning to engage. Point being, the switch has to trip at the point the engagement begins. Will test when I get home from work this eve. Buck | ||
| Natexlh1000 |
I'm interested in what you find. Your issue is a real brain grinder. | ||
| General_ulysses |
I'm no Buell engine tuner, but just because the TPS has been zeroed that doesn't conclusively exclude it as a possible culprit. If either the TPS or its wiring are bad, it could be experiencing a momentary signal dropout for just an instant before a normal signal is restored. Somebody posted the equivalent Ford part number (I think for a V6 mustang?) that applies to certain years of Ulys/XBs (I think the older ones). I think they were like $30-$40(?) Depending on how strongly you suspect the TPS, might be worth buying one and using it to eliminate your existing TPS as the cause. Just my $0.02 anyway, good luck getting it sorted. | ||
| Fotoguzzi |
you don't say mileage but yes a TPS can get a worn out spot or be set to rich and pump too much gas at one point I think.. happened on my Guzzi and that TPS is $270 some bucks.. Luckily there's an alternative and I now have a HARLEY TPS in my Moto Guzzi! cost $42.  | ||
| Rbuck53 |
Thank you for all the good info. Do you have the TPS part number for the 08 up xb? I tried to find it but couldn't. Thanks! | ||
| Sugarmcguinnmsncom |
Buck, Here you go. Throttle Position Sensor (TPS) same as 1993 Mustang Duralast #TPS213 AIRTEX Part # 5S5022 (07+ TPS) Standard motor products TH317 (07+ TPS) BECK/ARNLEY Part # 1580864 (07+ TPS) Duralast TPS4129 (07+ TPS) These came off the XB Cross Reference Thread here: http://www.badweatherbikers.com/buell/messages/142 838/723134.html?1380802845 | ||
| Rbuck53 |
Thank you...thank you...thank you! | ||
| Supacam |
Hi Rbuck, did the TPS replacement fix your problem?? I have a 06 that does the same thing to me, not so bad that the engine stalls but enough that i have to be wary of it so as not to loose momentum at low speeds and low side the bike. I hope your bike is good and look forward to an update! | ||
| Petro_freak |
Any idea whether the mentioned substitutes would work on an 06 Uly X ? cheers... | ||
| Rbuck53 |
Okay, here is where I am on this. Since my last post I have installed new plug wires and checked out the TPS circuit thoroughly. The TPS circuit is 100% working. The result from doing these things resulted in "no change". With that said I returned to the idle switch on the clutch. My motorcycle has aftermarket, adjustable levers installed. What I noticed is that, with these levers, my clutch starts to engage before the switch actuates. Actually the switch should trigger the idle higher before the clutch enters the friction zone. So...I modified the switch plunger length by fixing a plastic cap over the tip, effectively lengthening it about 1/16". Now the switch "clicks" before the clutch engages eliminating any drop in the idle while releasing the clutch. So far so good. Did this cure the problem? I don't know for certain. But I do know the hesitation is gone. Seems too simple right? I am going to operate the bike for a while and see if this "fix" proves out. Buck | ||
| Rbuck53 |
I am not familiar with the Uly updates from 06 to 08. Ck to see if you have this idle switch located under your clutch lever. If you do...ck its engagement point and compare it to your lever release relative to when the clutch is entering the friction zone. Let me know how you make out. | ||
| Froggy |
Rbuck53, that indeed likely was the issue. On the 08+ bikes, the throttle bodies are closed when you are not giving it any throttle, and the IAC system detects the clutch state, and when you are starting to release the clutch it dumps more air into the motor to help you get off the line. If the switch was thinking you were still squeezing the lever, it wouldn't open the air valve, resulting in insufficient air if you didn't twist the throttle enough. That is why it would bog down or stall. On the 07 and older bikes, they have the clutch switch, but it is only a safety switch, it does nothing but prevents you from starting the bike in gear with the lever released. | ||
| Rbuck53 |
Thank you for the reply and pointing out that earlier models also had a clutch switch...but serving a different purpose. That info will help avoid a lot of confusion. Buck | ||
| Supacam |
Thanks for the info Rbuck and Froggy. So mine is and 06 x, i can rule out the clutch switch issue. It's not so much of a problem, just a bit embarrassing at the lights when my big, black throbbing Uly see's the green and at the exact moment that I'm meant to disappear into the horizon, the bike instead sounds like it's about to stall until i can pick up the revs.... any further ideas froggy?? I've cleaned and reset the TPS, got a Jardine slung underneath, done all the usual preventative maintenance such as moving the ecm... any help appreciated. (oh, and sorry to jack your thread Rbuck) | ||
| Froggy |
Supacam - Are you still running the stock ECM (or at least stock tune)? I would be pointing to a fuel issue at this point, like it is not getting enough fuel. A Race ECM or a custom tune would fix it, in addition fix it running lean in general. | ||
| Supacam |
Hi Froggy, yeah a stock ecm but not a stock tune, having said that the bike hasn't been tuned by a professional as such, just the old "good map burned from someone kinda near my area with the same mods" so i don't know the origins of the original map. Thanks for the tip. Guess I'll have to roll up my sleeves and get a bit more brave with the computer. cheers Froggy. | ||
| Froggy |
Do a search on here for "square idle", I don't recall the details off hand, but you adjust a few cells on the fuel map around idle, and it has helped others with the same issue | ||
| Uly_man |
Depending on the year of bike there are 3 or 4 engine interlock switches I think. The kill switch, clutch switch, side stand switch and the gear box switch. And of course the BAS. They are all either "on" or "off". To test them for faults either un-plug them or through wire/ join them. The BAS will need turning off. It could be many things though but make sure the idle is set to 1050 rpm or it WILL bog down from idle. It is a known problem not doing this and setting the TPS right. | ||
| Firemanjim |
Show us your maps and we can see what idle area is like! |
