| Author | Message | ||
     Kcfirebolt |
I've searched the knowledge vault and may have found some clues, but I'm hoping some of you might add some suggestions. I have a 2003 XB9R with 33,000 miles on it. Recently the check engine light has started coming on under the following circumstances. If I'm running Interstate speeds of 80 to 85 miles an hour for more than 30 min to an hour, I will feel a sudden, but slight, loss of power and the engine light will come on. I haven't lost all power--the engine continues to rev and the bike runs. It does not sound different either (it doesn't sound like it is running on one cylinder). I drive to the side of the road and close the throttle. Before I get to a stop, the engine light goes out, and the bike runs normal at 75mph + for another 30 to 45 minutes before the power loss reoccrs and engine light comes on again. It appears to only happen at speeds over 75mph. After this happened three times yesterday, I drove the last hour home at 70mph, and it did not reoccur. Another possible symptom. The area surrounding the rear cylinder seems to get hotter than normal just after and maybe just before one of these episodes. I'm only talking about 20% hotter max. I don't know what to suspect. I've found a couple of posts that mention engine lights coming on due to rubbed wires, and I've sent a couple of offline questions to a couple of you regarding your experiences. I've also noticed that my cooling fan sounds a little ragged recently. Could the speeds over 75 be pinning the fan so it can't turn? Any other guesses? Thank you for your help and guidance. | ||
| Drift |
O2 sensor possibly. | ||
| Tpoppa |
That is an odd problem. Could a vacuum or vent hose be pinched or clogged? Perhaps pressure is slowly building until you feel the power loss. Good luck! | ||
| Izzinya |
"Drift Posted on Monday, June 27, 2005 - 01:18 pm: O2 sensor possibly. " im with you on this .... either that or temp sensor Izzinya (Message edited by izzinya on June 27, 2005) | ||
| Kcfirebolt |
Gowinward suggested this via email. Thanks for the ideas guys. I'm making a list and I'm going to run down each of these. How do I test the O2 sensor to see if it is working? "Charles, I saw your post on the Bad Web about your bike loosing power. My first guess would be the the bike is over heating and going into the skip fire mode to let it cool down. The constant 4000+RPM @ 80mph plus is a lot more heat load on the cooling system than 3000 RPM @ 70. I would take a look at the oil cooler and make sure it's real clean, I use Simple Green on mine. Any dirt or grim biuld up on it is going to really reduce it's effectiveness. Same goes for engine cyclinder cooling fins. If the fan is sounding rough I would also reach into the fan and spin the blade by hand and feel how smooth the bearing feels. I wouldn't think the bearing for the fan would be shot, but a good sanity check never hurts. Hope that helps." | ||
| Blake |
Cylinder head temperature sensor. | ||
| Ortegakid |
HEAD TEMP SENS, MINE DID THE SAME THING | ||
| Johnk3 |
o2 sensor is cheap, just replace and take that off list. | ||
| 12bolt |
Follow the manual as to check the engine codes, it will tell ya which sensor is going bad. Mine did the same thing except I didn't notice any loss of power and it turned out to be the o2 sensor. | ||
| Gjmcmanus |
If you have a high voltmeter and time you can check your O2 sensor yourself. The engine must first be fully warm. Attach the positive lead of a high impedence DC voltmeter to the Oxygen sensor output wire. This wire should remain attached to the computer. You will have to back probe the connection or use a jumper wire to get access. The negative lead should be attached to a good clean ground on the engine block or accessory bracket. Cheap voltmeters will not give accurate results because they load down the circuit and absorb the voltage that they are attempting to measure. A acceptable value is 1,000,000 ohms/volt or more on the DC voltage. Most (if not all) digital voltmeters meet this need. Few (if any) non-powered analog (needle style) voltmeters do. Check the specs for your meter to find out. Set your meter to look for 1 volt DC. Many late model cars/motorcycles use a heated O2 sensor. These have either two or three wires instead of one. Heated sensors will have 12 volts on one lead, ground on the other, and the sensor signal on the third. If you have two or three wires, use a 15 or higher volt scale on the meter until you know which is the sensor output wire. When you turn the key on, do not start the engine. You should see a change in voltage on the meter in most late model cars/motorcycles. If not, check your connections. Next, check your leads to make sure you burn through them, etc. then start the engine. You should run the engine above 2000 rpm for two minutes to warm the O2 sensor and try to get into closed loop. Closed loop operation is indicated by the sensor showing several cross counts per second. It may help to rev the engine between idle and about 3000 rpm several times. The computer recognizes the sensor as hot and active once there are several cross counts. You are looking for voltage to go above and below 0.45 volts. If you see less than 0.2 and more than 0.7 volts and the value changes rapidly, you are through, your sensor is good. If not, is it steady high (> 0.45) near 0.45 or steady low. Might be a place to start, if you are a little mechanically inclined. It will let you know if the O2 is still alive or not. To make sure it is switching correctly you would need to have an oscilloscope, MODIS, or DMOV to look at the waveforms. A good sensor should switch from between approximately .175 volts and .800 volts in less than 100 milliseconds. (Message edited by gjmcmanus on June 27, 2005) | ||
| Kcfirebolt |
Wow. Thanks for the explaination. I'll print it out, take it home, and see if I have the right materials. THank you for sharing your knowledge. |
