| Author | Message | ||
     Tempest766 |
Granted, I'm using a really lousy and cheap DArsonval multimeter that only has 10kohms internal impedance, but... without removing my TPS I show a resistance across the pot of 440ohms. testing the center tap to +5 (top red lead) I show 440ohms (0v) with throttle closed and 120ohms (3.6v) with throttle open...asuming a 5v sensor loop and calculated using Kirchhoff's law. My numbers cannot be precise because of the limited display precision of my meter, but you get the idea. My online reference part is the Wells Electronics TPS4129, which posts say is a drop-in component for the 2008-xt. The difference being that their graphic has the ground and +5 reverse to what they are on the buell part. They show +5 on the bottom and in the 2008 xt it is clearly the red and white top wire. For a normal pot the reversal should not make a difference. It concerns me that they don't list internal resistance, range, and power dissipation on their data sheet. I'd expect an OEM manufacturer to give those values, but they don't. they do say that the unit (when installed in their target application should yield 0.2-1v low and 4.6 v high...which doesn't make sense unless you know the input voltage and application. My throttle movement was smooth, with no erratic jumps or dead spots. If someone can show me that my voltage ranges are outside of what the ECM can tolerate then I'm willing to concede that the TPS might be flaky, otherwise it seems the problem is elsewhere, no? I also ran the bike up to warm operating temp and tried to see if I could coax an engine light or sputter by torquing the ECM connectors but it did not hiccup or throw an error. | ||
| Natexlh1000 |
10K??? Dude, we live in the future! Just get this: http://www.harborfreight.com/7-function-multimeter -98025.html It doesn't even have vacuum tubes! | ||
| Hugie03flhr |
You said the engine light fluttered /flashed . I would think the ECM would store that and it might give you a place to look. The fact that it doesn't stall and it returns to idle is strange because you are not drive by wire. In other words the bike would stall if you opened the throttle while the ECM was giving just enough fuel for idle. Or am I misunderstand what happens when it acts up? Is it like a rev limiter where the bike will idle but sputter like crazy when you give it the gas. Or does it die (bog down while in gear)when gas is applied but when you let off, it idles? Because it's so erratic, I don't think it's related to heat but possibly a fuel pump not maintaining pressure. | ||
| Tempest766 |
The yellow engine light flutter was a once occurrence, only the last time I rode. It's been "bogging down" since the middle of last summer and has gotten worse. re fuel pump - Are these bikes prone to vapor lock? | ||
| Tempest766 |
re - harbor freight multimeter. because I want to see a continuous sweep on a needle instead of a digital readout. I have an expensive fluke meter and a 250mhz digital storage scope but an analogue readout is easier to see erratic behaviour on when checking resistance. | ||
| Etennuly |
Prone to vapor lock? Not really, there have been times where it has occurred and was noted, but most of those that I recall having read were in 90F heat and above usually with a low fuel level. Some Uly owners lined their inner fuel frame rails with aluminum backed self stick insulation. My '06 has never had this problem. | ||
| Tempest766 |
Can the 08 XT generate error codes without displaying a CEL or is the CEL intrinsic when any error is detected? | ||
| Natexlh1000 |
If the range of voltages it sees are within the expected range, it won't smell a rat. If the +5V source is grounded somewhere, it will cause codes and also mess up other stuff that needs the +5V. | ||
| Hugie03flhr |
I've never heard of anyone having vapor lock but I have seen many crazy things happen with fuel pumps. Everything from bad connections to holes or cracks in the fuel pump pressure line. The TPS will usually give a jerky or a very erratic throttle response and if it completely dies, I would think it would throw a code. The other thing that comes to mind is the fuel pressure regulator acting up. Idk of anyone who install a fuel pressure gauge but that might be a way to eliminate your fuel system as a problem. I've never played with the ECMSPY that's sold on eBay and uses an android phone to see what's going on but in your situation, it might be worth it. Good Luck! I hate seeing good bikes sidelined over a gremlin... | ||
| Arry |
"...vapor lock?" Probably not, but there is a vent hose, that could get blocked. I hate to say it, but the ECM can give a weird assortment of symptoms, that might come and go, and seem to crop up when the bike is warmed up. You say Harley (the local dealers shop?) butchered the seat. Maybe the seat was hitting the ECM connector, and that was their "fix". (I hate letting the shop monkeys touch my bike.) Now, instead of the seat base pressing against the connectors, the seat foam could be pressing... The connectors don't get damaged, but the pressing against them causes problems with the soldered connections inside the ECM. | ||
| Tempest766 |
I'm not keen on WAG (wild ass guess) replacing a 400 dollar component (ECM) if it isn't really the culprit. I may contact the OEM to see if they will accept the unit back for diagnosis and testing. | ||
| Arry |
You can have a stored code, even if the CEL is not on. Have you checked for stored codes? Mine had various sporadic symptoms, for quite a while (many months), before it finally stored a trouble code. Do you have a service manual? There's a procedure to retrieve codes, they display as a series of flashes (of your CEL). (I didn't go back through this thread to see if you've already done this) | ||
| Djack95 |
The VEMO V20-72-0406 TPS sensor is a perfect replacement part for the post 2008 models. You can find it on Amazon for less than $62. I agree you should check yours before a change, but if you are near 30 000 miles, your sensor has probably past his best ... Did you do your TPS reset ? On post-2008 models, the operation is simplified to a maximum and consists of complete 3 round trips with the throttle grip once the ignition is switched on and the engine light is switched off (handlebar switch to "Run"). Each extreme position must be held 1 second. You can then turn off the ignition. Personally, I perform this ritual each time I inject a new cartography, or at least once a month. I'm not sure this will cure your problem, but it might help. If it does, you should consider changing your TPS sensor ... | ||
| Tempest766 |
I finally got around to checking for stored ECM error codes and only one is stored: 11 (TPS high or low). This, to spite my testing of the resistance of the actual component, although not tested after the bike had heated up. It could also be that there is a wiring harness problem between the TPS and the ECM. That is next on my list of things to check for. Pulling the TPS and replacing is a last resort since in typical buell fashion, swapping out involves a 3d jigsaw puzzle and muttering many profanities in the process. I do not relish removal of the throttle body and the TPS mounting bolts are too long to remove as-is. Not to mention the price of a new pot. re: TPS replacement...good to see another replacement option but B2C through amazon (really, anything through amazon) doesn't leave me with the warm fuzzies. So I'm still looking 80+ to 120+ through an autoparts store. Oh BTW: a google search for "xb12xt ecm codes" yields the location of an online PDF of the electrical diagnostics manual for the 08 and newer xb12 bikes. I had the regular maintenance manual but not that one. I also contacted the OEM of the ECM and they can bench test the ECM for me. We didn't discuss price. I may still go that route to rule out seat stress or long term heat problems. Will advise... Final thought. Are the Kent Moore B-48115 breakout boxes still available from a real reseller? *** addendum *** the stored code 11 I got may not be valid either since I read the ECM code while the TPS was disconnected. I have no idea when the code 11 was generated since multiple occurances of the same code only register once per read loop. D'Oh! (Message edited by tempest766 on March 11, 2017) | ||
| Steveford |
On my 06 I was able to pull the TPS without removing the throttle body. It's only a hunk of plastic and they can get wear and slop in them. I fixed mine by packing it full of dielectric grease for a lubricant and then preloading the TPS a little bit during the reinstall. Before that my bike was bucking and surging like crazy but no longer. | ||
| Hughlysses |
I also contacted the OEM of the ECM and they can bench test the ECM for me. We didn't discuss price. I may still go that route to rule out seat stress or long term heat problems. As an alternative, you might find a Badwebber with a spare ECM they'd be willing to loan out so you could try it. A lot of people buy race ECM's and wind up with a leftover stock ECM. | ||
| Tempest766 |
@Steveford - I was eventually able to remove TPS without pulling the throttle body. We'll see if it goes back on easily. Actually the hardest part was finding a 7mm box wrench. Most places stock 8mm and up. The 08 TPS is a different part than your 06 uses. We're under the ice at the moment but now I've got lots more electrical diagnostics to do. | ||
| Steveford |
Hope you get it sorted out. My Buell knowledge pretty much ends with the 2006 line up but mine was bucking, surging and the CEL would flicker for a second. When I'd put an Allen wrench into the idle adjuster cable the TPS voltage would jump all over the place so preloading it a bit was the cure. Hope at least some of this is applicable to your case. This Winter can't end soon enough to suit me! | ||
| Tempest766 |
After doing a lot of electrical diagnostics and ruling out cabling problems, bad TPS, or bad IAC, my problem is now reproducible. I started the bike, let it come up to operating temp when the fan kicked in, and then rolling on the throttle caused the engine to die consistently when it hit about 4500rpms. I hope to have youtube video of the process online shortly. | ||
| Johndd |
I had the same issue due to putting new plastics on my 06 (restoring to original condition). It was an airflow issue. Try running with filter housing cover off. | ||
| Tempest766 |
@johndd -- Interesting. I wonder if my filter is just plain clogged beyond being useful. It had become saturated with oil way back before I did the breather reroute, and I washed it with Dawn and have been using it ever since. Will try the same test with an unfiltered intake (which shouldn't hurt the engine if only for a few minutes). | ||
| Tempest766 |
Well, it was a good thought but no dice. 40F and sunny here after work. I removed the air filter and started it up, then let it warm up to get the fan running. I then tested the throttle for a few minutes, running at different RPMs, up to 5500ish without incident. I bundled up and jumped on the bike to ride down the road and got about 1/2 mile from my house before the engine tried to die on acceleration. I got turned around and nursed it back to my house at 30mph and keeping the RPMs under 3000. It bucked once even under 3000rmps. | ||
| Johndd |
Modern fuel with ethanol in it can break down over time and gum up the engine. Oxidized fuel will look darker than unoxidized. You might siphon some out and check it versus a good source (recently pumped at local station). The mechanic I take my 06 to originally thought it had this issue (instead of poor airflow). | ||
| Tempest766 |
Tank was filled from near empty less than a month ago. I've considered bad gas as well, but this problem started intermittently last summer and has gotten worse over time, through many refills...I'm beginning to consider a fuel pump problem (scares me because of the labor involved in changing it) as well as wanting to test a different ECM on the bike. IDS will let me return an ECM withing 45 days if I order a racing unit for testing and don't want to keep it. I still need to do a video of the problem and post it. Would be much more descriptive of the symptoms. | ||
| Tempest766 |
I promised to post a video of the problem I'm having with my Uly. This annoyance started as a minor inconvenience when I was cruising and the engine was hot, but now I can consistently reproduce the problem just by starting up the bike and letting it warm up to the point when the fan comes on. This is a Youtube video that is very descriptive of the behaviour. https://youtu.be/oL3-aMjYsrw | ||
| Mark_weiss |
After it quits, will it start right back up? That is really strange. If the problem were with a switch or general wiring, I do not think that the fuel pump would not continue to run. It seems as if the spark is cut, but nothing else. I noticed that the neutral light does not blink and that the muffler servo does not cycle. Things that might happen if there were a momentary full electrical fault. It is also telling that the problem is repeatable at a particular rpm. This really seems to point to the ECU. That is the only part that "knows" the rpm. Even coil breakdown is usually ragged and not so rpm consistent. | ||
| Tempest766 |
@Mark_Wiess - yes, after the pump reprimes it will start back up. Sometimes exhaust actuator opens, and sometimes it does not. It does cycle on power-on when following the reset process in the service manual, so I'm assuming the actuator itself is good. One interesting note: My air filter is off right now, and when I did the reset with a hot engine (right after a throttle induced stall) I got a backfire through the air intake and a noticeable flame. (Message edited by tempest766 on March 26, 2017) | ||
| Tempest766 |
What would you guys do next? Pull the fuel pump, or swap the ECU? | ||
| Steveford |
Wiggle the connectors on the ECM. If you press down on the one that sits the highest up and it dies you've found the problem. I finally pulled the battery tray, drilled some holes in the inner rear fender and mounted it as far down in there as possible. I still can't imagine why they didn't stick it back by the BAS in the tail like they did with the X1. There's plenty of room there and they KNEW the ECMs were getting crushed and the response was an ineffectual plastic block and an Allen bolt. (Message edited by SteveFord on March 26, 2017) | ||
| Etennuly |
I would swap ECM. Fuel pump failure would not let it run and fail consistently like that IMHO. That backfire you had says ECM to me also. |
