| Author | Message | ||
     Snoman |
I was hoping to figure this out on my own but am caving in and looking for help. It all started out last summer when I serviced the bike before a long ride. Among other routine service I reset the TPS (which I've done successfully a number of other times). Not far into my trip I noticed that the idle would hang around 2-3K when stopped. Not wanting to cancel a long trip, I visited a dealer who still worked on Buell's. He reset the TPS again and claimed I had an intake leak. It idled better, but would still sometimes hang on idle and when it did idle down would pop and sputter. As it ran fine at highway speeds I finished out my trip. One I got home, I tore into it and replace the intake seals. After putting it back together and doing another TPS reset it ran the same way. I checked for another intake leak thinking I didn't get the new seals seated - nothing. Just for fun I changes the seals out for new ones again and threw in injector seals while I was at it. Same thing. At that point I recalled the dealer saying that the O2 sensor was also throwing sporadic readings so I replaced it too. Still ran the same. After several rides and more TPS resets, I found that the only way I could get it to run well again was with the TPS set around 2.4 and the APV around 125%. This spring I've been for a few rides and tinkered with it only to find the same thing - the only way it idles well is with the TPS set low and the APV adjusted high (after riding, not manually setting it). So... I'm not sure what to try next. I'm fairly confident that it's not an intake leak, the O2 sensor is new (presumed to be good), and the bike runs well under load. Since it runs well at high RPM's and under load I've been assuming that fuel delivery is fine. Is this a poor assumption? Is there any chance that the TPS sensor is bad? How do they act when they go bad. When idling and hooked up to ECM Spy I can see the TPS value bounce around a little but within 1 degree. Engine temp and air temp readings appear to be good in ECM Spy too. Anyone have more experience with this than I do? Eric. | ||
| Sagehawk |
TPS sensor readings should be smooth increase in your voltage reading as you roll throttle on and off. watch it in ecmspy or if needed , get in to sensor and put ohmmeter on and watch it on ohm value setting. Have you done a hard tps reset on the bike? You need 0 lash in the tps to butterfly mount. threads are here on how to do that. I know you said no intake leaks but>>>>as Tootal said a while back, it took him 6 trys one summer to solve his intake leaks. ECM remounted? Grounds gone through in all points of the frame? recheck your o2 sensor wiring if you feel you have a good sensor. A good datalog will help analyze what is going on as well. a last thought is check your butterfly shaft and make sure it is not in the process of breaking. I don't know if they snap all at once or they crack and start drivability problems for a while driving you nuts till it does break. Just saying! | ||
| Tootal |
If you've tested for a vacuum leak and they are good then the tps may need to be put at a hard zero as the Sage one has said. The tps sensor is adjustable. Loosen both screws and rotate it clockwise about a 1/16" and tighten the screws. Now do a tps reset and go ride it for 20 minutes or so and then do a hot tps reset. Then ride it at a constant speed over 3000 rpm for a while. Also, if your idle is hanging it might be set too high. Back it down to 1000 rpm if you haven't already and see if that helps. If set too high it will hang. | ||
| Hunger |
Wow I didn't even know it's possible to hard-adjust the TPS. Snoman -> I don't want to worry you but I had a very similar issue. Ended up replacing the whole throttle assembly because I couldn't find the leak source. And only that did help. I won't tell you to reset TPS because you've done that a number of times. There's no magic there. Hook the ECMSpy up, take off the airbox and compare TPS degree reading with the actual position. If it looks sane the TPS is OK. Have you tried 'spray testing'? Do it: https://www.youtube.com/watch?v=5MvohPCZazY Spray the surroundings too. Injector seals in particular. Good luck! | ||
| Sagehawk |
Hunger, did you ever test that manifold setup to see if you had a crack or whatever in it? You dropped thread after installing new stuff but I've still wondered about that. We're the spigots good and round with a good finish on them. Flanges in good shape?. Still curious about that! | ||
| Etennuly |
I see you have done a lot with the TPS and fuel. On that note did you check for carbon on the throttle plate edges? It will mess up an otherwise proper TPS reset. Stepping back towards basics a bit, did you pull the spark plugs? If they are black they are possibly fouled to where they can run good off idle and up. Did you check the spark plug wires for rub through? | ||
| Hunger |
Sagehawk -> Yes, the flanges are out of the question. I've replaced them first, only when it didn't help, the throttle. You've motivated me. I took the old one apart today. Here's the post: http://www.badweatherbikers.com/cgibin/discus/show .cgi?tpc=32777&post=2542745#POST2542745 (Message edited by Hunger on May 14, 2016) | ||
| Steveford |
You should replace that TPS, it'll give you nothing but agita. | ||
| Snoman |
First off - thanks for all the suggestions. There were a couple things I hadn't yet tried so I just finally got around to digging into this again. While I haven't had time to work on my Uly until now, I have still been riding it. I've probably logged 1,500 miles since my last post. It's actually been running really well but I'm still not content - more on that later. - Checked for intake leaks again using both propane method and spraying with brake cleaner. As the bike has been running and idling really well I didn't expect any leaks, and didn't find any. - Reviewed data from all inputs via ECM Spy and didn't find anything that looked out of the norm. The only thing that looks off to me is that the TPS is 2.3 at idle and the APV value is 121%. - I disconnected the TPS and checked it using an analog multimeter - very smooth and constant readings as the throttle was operated from the grip. - Checked spark plugs (new about 5,000 miles ago) and found them to look really nice - light tan colored burn. - Performed a hard TPS reset and was excited to see that the new position found the TPS slightly clockwise of the old position. Performed a standard TPS reset using ECM Spy , fired the bike up, and it idled near perfect. The idle was a little high so I turned it back a bit so it was idling around 1,050 RPM. Sounded great. Took it for about a 20 minute, maintaining about 3,200 RPM to relearn its APV. Once home, I left the bike running and plugged back into ECM Spy. The idle was a little high so I backed it down again. TPS – 1.6%; APV 137%. I’m really tempted to just leave it alone since it’s running better now than it has for a long time. Smooth idle, smooth power, no coughing, popping, or backfiring. My only concern is that the TPS and APV can’t be set where they should be. Obviously the APV is accounting for the low throttle position setting, but I don’t know that everything else is okay if left this way. Won’t the fuel mapping be off with this setup, or does everything come out in the end? For a little more background, this is an ’07 XB12X with 57,000 miles. The ECM hasn’t been relocated yet, but probably should be. It has the plastic stand-off and I’ve added another 3/16” to the height because it was apparent that the seat was still rubbing on the connectors. A can’t find any cracks in the connectors or ECM and it hasn’t acted up since I added the extra height to the stand off (previously it would occasionally cut out and the gauges would cycle during the middle of a ride). I haven’t checked all the grounds again but did a few years back, removing paint in places to ensure good contact. O2 wire looks good. Throttle body and butterfly plate were cleaned well when the throttle body was out to replace intake seals. I haven’t done a vacuum leak test yet, but should probably look into doing that. One thing that did look a little odd to me was that there was quite a bit of play in the throttle shaft. On the cam side you can wiggle the shaft back and forth in the throttle body housing quite a bit in my opinion – probably .030-.040”. To get the butterfly fully closed, I can see the shaft jump a little bit at the end of its travel. It doesn’t seem like the shaft is cracked but I suppose it’s possible. It looks more to me like the bearing surface(s) on the shaft or throttle body housing are worn. Could this be the problem and would it explain the bike running well but with the TPS and APV off? After reading posts from Hunger and Tootal, I’m wondering if my throttle shaft bushings are trashed. Would this be enough to cause this leak though??? | ||
| Ratbuell |
The TPS numbers are a guide-range. Every bike is different. Find your bikes happy place and ride it, regardless of a 2.4 or a 2.7 or a 1.3. All that number is, is a representation of what the computer has marked as its "closed/zero" baseline position. | ||
| Mark_weiss |
For BMWs, when throttle shaft bushings become too worn, the throttle blade can reach a stop position at slightly varying angles, while this does close off the airflow, the TPS reading can change each time. This confuses the ECM. Additionally, air leaking around the throttle shaft can cause some issues, depending on how the system 'measures' airflow. | ||
| Hunger |
Snowman, for me your symptoms are obvious, you have an intake leak. There is no magic, if you look at the valve at 0% TPS and it looks closed then it's closed  If there's no stuttering or jerky feeling you might actually leave it like that, in my case I had plenty, in your case it's just ECM readings annoying you. The only thing that I would be worried about is the shaft play - there shouldn't be any. You could record it and post here so that we can see how bad it really is. In my case I just got enough of searching, installed brand new throttle and problems were gone. That's what the dealership would probably do Also you may have a look if you have the 'emissions' cap in place: http://kentie.net/article/buelltips/throttlebody.j pg If the cap is missing it may just add up to the total leak - alone it's not an issue AFAIK. | ||
| Tootal |
The cap is only an unfiltered air way. Since it's above the butterfly it has no impact on vacuum leakage. Did you pull the fuel injectors out? At 57,000 miles the o-rings may have gotten hard and are leaking. The shaft bushing are teflon and split. They could be worn or the shaft might have wear. You can pull the bushings out without removal of the shaft although it might be tougher on the tps side. There are no "official" replacements however somebody on this forum located a replacement from somewhere but I'm don't remember where. Might be able to search this out. | ||
| Snoman |
Thanks for the input Hunger - although the bike has been running pretty well, I think I've arrived at the same consensus - that there must be a throttle body (intake) leak. I did actually take a video the last time I had the airbox off. It's not a great video, but should show the slop in the throttle shaft. I think it's more than it should be, but would appreciate feedback from others. I'll have to search the forum to find the source for the bushings. I noticed in the parts manual that nothing beyond the throttle body assembly (with butterfly valve) is considered serviceable. https://drive.google.com/file/d/0B5kd6h9TivAHMWwwe WpnT0R2aGM/view?usp=sharing Tootal - to your point regarding the emissions cap, you can see in the video that I have capped it, but didn't notice any change. I did also have the injectors out when I replaced intake seals and replaced the O-rings at that time. For what it's worth, they still felt pretty soft in my opinion for 5X,XXX miles. | ||
| Tootal |
Holy crap! You weren't kidding! I'd pull that all apart and get new bushings and make sure the shaft was okay. | ||
| Hunger |
Snowman, your intake leak is not the worst problem you got  | ||
| Ratbuell |
Out of curiosity, how many miles and is your breather setup stock, or have you rerouted it (taking any hope of throttle body lubrication out of the equation)? | ||
| Snoman |
I think I found the reference Tootal made to the replacement bushings here: http://www.badweatherbikers.com/buell/messages/142 838/771988.html. It looks like some modifications are needed to get these to work. Does anyone have dimensions handy (e.g. ID, OD, wall thickness, flange thickness, flange diameter, etc)? Measurements from the shaft and throttle body would be helpful too. It seems like a closer match should be available somewhere, if not an exact replacement. As for the breather re-route, I did do this mod at 22K miles (35K miles ago). After searching for the thread above I read about plenty of questions/accusations regarding possible connections to broken throttle shafts. While it might not be conclusive, it's hard for me to argue that a worn bushing isn't related to a lack of lubrication. I've been considering undoing this mod anyways because I didn't install a collector and am getting sick of having to park over a piece of cardboard in the garage to avoid dripping oil on the floor. I don't remember noticing a huge difference in idle performance when I made the mod anyways. If/when I decide to tear into this to replace the bushing, what are the odds that the shaft will be okay, or will I end up tearing the throttle body apart to replace that too? | ||
| Tootal |
With that much play either the bushing is totally shot or there is a combination of shaft wear and bushing wear. Usually bushing material like this is not meant to be lubricated. However dust can make it's way in there and affect the bushings. The felt ring is supposed to be a filter but it doesn't get it all. Even in the blown up pictures I have above you can see how rough they are. They were out of Maximum's bike and I don't know the mileage he had on it at that time. I recommend you pull your TB out and rebuild it like Xbimmer did. Change all the o-rings etc. | ||
| Snoman |
Update - I coughed up money for a new throttle body assembly before they're gone. I installed it last weekend and it completely took care of the fueling issues. Engine fired up and idled smoothly after TPS reset, ran better than I ever remember it running when lugging at low RPM's, doesn't seem "cold blooded" anymore, and APV settled around 102%. When time allows, I'll be tearing the old TB apart are rebuilding. I'm really curious how bad that bushing and throttle shaft are. Maybe I'll find another leak that was hidden. Thanks everyone for helping to diagnose this! |
