| Author | Message | ||
     Nobuell |
I have ridden my XT only a handful of times over the past 6 years due to racing my Buell 1125. I am not racing this year due a 2018 injury that required 2 surgeries. Last week I pulled the XT out of storage, changed the fluids and performed a general maintenance. After replacing the battery and filling the bike with left over race gas, the bike fired right up on first try. Now the operating issue. A few years back the bike started to have a cold idle issue. It starts up and runs initially at high idle speed but then drops down to approximately 900 RPM after approx 45 seconds and promptly stalls. The bike will not idle when cold. Once warmed up, the idle operates like normal. I have also noticed that the bike has a dead spot at approximately 3300 RPM to 4000 RPM. Once above 4000 it accelerates like it should. The dead spot almost seams like is not getting fuel, almost feels like the brake is being held. I checked the following last Sunday: 1. Re-set the TPS multiple times. Verified smooth operation of the TPS using a analog multi-meter 2. Pulled the IAC out and cleaned the passages and the throttle body in general. The IAC cycles when the key is turned on and off. 3. I replaced the CPS with a spare and verified the cables were not running parallel to the regulator wires possible inducing EMI issue. 4. Cleaned all of the applicable connectors with electrical cleaner. 5. Verified the intake seals are not leaking with electrical cleaner 6. Verified that the ECM connectors are sound. I modified the ECM mount long ago to assure the seat does not break the connector. Also, the ECM was purchased from Buell as part of the comfort kit upgrade. I still have the original ECM that I can swap out just to see if the issues are corrected. I would like to get the bike connected to the computer to monitor the systems. I had ECMSPY on a long dead portable computer. I have the connection cable. Is ECMSPY the best current method to monitor the bike. Are there other options out there? I checked some old computer archives and have the following application files on hand: ECM_Spy_1.12.27.exe and EcmSpy_Mono_2.0-Setup.exe. I also have the various tuning guides and instructions. Any thoughts or guidance on the operational issues or the computer monitoring will be appreciated. It has been awhile since I have had to do trouble shoot on a bike. My race bike had very few issues. It feels pretty strange riding on the street again after racing for the past 6 years. The bike is as fun as I remembered. Just need to get acclimated too much less HP. Best | ||
| Ourdee |
I still have the original ECM that I can swap out just to see if the issues are corrected. You are doing all the heavy lifting here. I would throw the OEM ECM back in for a free check. Remember that hesitation just off idle in the emissions regulated world. | ||
| Hughlysses |
At least one of your issues is related to engine temperature. You could check the Intake Air Temperature (IAT) sensor (located on the base plate of the air box) and the Cylinder Head Temperature Sensor (located in the rear cylinder head near the spark plug). I imagine you can look at both of those in ECM Spy and see if the readings look sane. The IAT can get glopped up with oil which will throw its reading off. Either sensor could have a damaged wire or the sensor could have failed. | ||
| Nobuell |
Hello Hughlysses, I forgot to mention that I did check the IAT. The resistance did correspond to the room temperature. I will have to check the head temperature sensor. I did replace it a few years ago. I read about ECMdroid today. Of ECMspy and ECMdroid, any idea provides the better tools for diagnostics? | ||
| Natexlh1000 |
Just out of curiosity, what type of race gas is it? My friend used to have a drag racing snowmobile that ran race gas. He found that it decomposed rapidly. Lots of Toluene in it too. It wasn't gas really. It was something that acted like gas and resisted pre-ignition as if it was 102 octane. Just saying, what are the odds that it's just a snoot full of "Wrong" gas? | ||
| Ratbuell |
If it was a preexisting issue, it probably isn't the current fuel. You say you race an 1125 so I presume you're familiar with the Buell EFI, and you're doing your TPS resets on a HOT engine, yes? Do them cold...and they misbehave. Idle issues could be - from my early-EFI-car days - a ganked up IAC motor. Basically a cone-shaped piston that air-bleeds the throttle body for coldstart. Gummed up / plugged with soot/oil, and you can get a coldstart stall. You could also, once you exhaust other methods, simply give a twist or two on the throttle-stop screw to up your idle speed some. My 06 has a remote idle speed adjuster; they ditched those for '08 but there's still a screw on the throttle body. You didn't mention exhaust, but a mid-RPM flat spot could be a malfunctioning exhaust valve (stock muffler), or a missing valve / aftermarket exhaust "feature". | ||
| Nobuell |
Natexlh1000 - It is 100 octane unleaded Sunoco GTX. It should not be the problem since I have also run a couple of tanks of pump gas. Does smell good when running. Reminds me of the pitts.  Ratbuell - I had the IAC apart and cleaned it along with the throttle body. I have yet to try looking at the exhaust valve as I do have the stock pipe. I installed ECMSpy on my computer yesterday and will try performing diagnostics and report back. Thank you for the suggestions. | ||
| Nobuell |
Success, I was able to get ECMspy Mono operating and communicating with the bike. After a couple of loggings, I was able to determine that the TPS range was shifted such that it would show 10% throttle open regardless of the number of resets. According to the Buell Electrical Trouble Shooting manual, indicated positions over 5% can contribute to idling problems. The TPS exhibited smooth operation however the starting point resistance appeared to be shifted. I also found that the AFV to be 85% indicating a rich mixture compensation. The O2 sensor average reading were very high on the rich side indicating a failing O2 sensor. The inlet air temperature and cylinder head temperature were in order. I purchased a replacement O2 sensor and TPS from O’Reilly’s. Both parts require a good deal of work to change. For the O2 sensor all under seat components including the comfort kit fan tunnel must be removed. Not a difficult job but a PITA. The throttle body must be removed to replace the TPS. This can be accomplished without rotating the motor but it is difficult, slow work. While the Throttle Body was out, I pulled the injectors and checked the seals, thoroughly cleaned the TB and idle circuit. The intake seals were replaced although I replaced them a few thousand miles ago. They still looked brand new. I also cleaned all of the sensor and injector plugs. I installed new iridium plugs and inspected the Magnecor spark plug wires for signs of wear. After re-assembly, I reset the AFV to 100% and verified the TPS operation. It now indicated 4% open eliminating the possible idle issue caused by the high open position of the original TPS. I had two issues to correct; bad cold idle and a dead spot from 3500 to 4,000 rpm. The idle was back to normal and the dead spot is eliminated. The bike felt like new again. I believe that the O2 sensor and perhaps the TPS were degrading over time. The O2 sensor was telling the ECM the mixture was rich and the ECM was compensating by lowering the AFV. This was leaning out the fuel across the board diminishing power and operability at a slow rate making it hard to notice incremental changes in performance. I believe the idle issue was caused by a combination of the bad TPS and lean AFV due to the failing O2 sensor. I have been riding the bike to work every day. This weekend, I plane to connect the bike to the computer and verify the AFV is stable and verify the O2 performance. I will check back if anything looks odd. Now the bike runs better than it has in a few years. | ||
| Uly_dude |
Hello Nobuell. Thanks for the updates. Very useful for me as I'm sorting out some of the same issues here. Would you mind telling me which O2 sensor from o'reilly's that you used? I might go pick one up for an afternoon project. Thanks! | ||
| Nobuell |
Uly dude, it was a Bosch # 12014. | ||
| Uly_dude |
Thanks Nobuell! After reading your post I wonder if it's easier to rotate the motor vs removing the heat shield kit, etc. I've removed that stuff before to get to the shock, it's not fun..... | ||
| Motorfish |
I replaced my stock O2 sensor with the Bosch 12014, and it only lasted a few thousand miles. I’ve read other folks here have not had good luck with them either. I bought a NTK NGK 21002, but haven’t put it in yet. Just my cents worth. | ||
| Uly_dude |
Thanks for the 3 cents worth Motorfish. That's good to know. Did someone at the store tell you the NTK were better? I wonder which one Harley puts in the bikes?? I've gotten 25K out of this one. G | ||
| Motorfish |
I started getting the CEL coming on at highway speeds. The code history said it was a code 13 I believe, or whatever number the O2 code is. I didn’t actually talk to anyone about the NTK, just going by what others here have stated. Usually pretty accurate. They are a bit of a pain to replace, just takes some time and patience. Overall not too horrible, but it’s something you don’t want to do often. Hope this helps. | ||
| Nobuell |
The Bosch 12014 is the same as stock. It lasted 45K miles. | ||
| Tootal |
I appreciate the conversation as I've gotten the "money" light recently at highway speeds. If I slow down it goes off. ECM SPY says O2 sensor so next on the agenda. Thanks for all the info! | ||
| Tootal |
So I started working on the Uly today. I have the Comfort Kit and boy does that make it a pain in the keester!! Dropping the saddlebag mounts to get the under seat panel out! Really? Oh well, it's all apart. I have a new fan to install. The old one was working although at one time it was making funny noises but I think it was just some leaves got in there. I manually spun it and it didn't sound trashed but not good either. I hope the new one is good, it's been sitting on the shelf since 2007! One of those things I bought just in case. I was missing a screw on the fan mount too. I noticed no loctite on any of them. There will be upon assembly! I'll put it back together tomorrow. I hope my memory last that long. |
