| Author | Message | ||
     Tempest766 |
I had noted a problem last fall where after riding for an hour or two (engine heated up and at operating temp) my engine RPMs would sometimes drop to idle during an acceleration, usually during a quick acceleration to pass someone, or to "open it up" on the four lane. letting off of the throttle and dropping down a gear "usually" caused it to catch and give power again. Yesterday I went for a 166 mile ride with some sport bike guys and true to form, the thing started acting up after about an hour of riding, but this time it has gotten much worse, dieing during normal 3300rpm highway cursing, and a couple of times the check engine light fluttered. I was able to make it home, but certainly cannot risk riding if the engine is acting up like that. It was 50s and 60s all day so the engine stayed pretty cool and I got better gas mileage than I normally get, 43 as opposed to 37ish. Any thoughts on what could be causing the engine to just lose power or even die under acceleration or while cruising (after warmed up)? 2008 XT with about 28k miles on it. | ||
| Ourdee |
XT with low seat? Hour in the saddle. About enough time to warm the seat under your rear end and let it sag down enough to push on the ECM connectors. Check for cracks on ECM around base of connection parts. Start engine with seat off. Try and move wiring harness where attached to ECM. If it dies or throws an engine check light. Don't feel more than three hundred dollars worth of sad. Contact IDS. | ||
| Ramman4x4 |
Adding link because I didn't know who IDS was. http://idspd.com/xcart/ | ||
| Ourdee |
Sorry, I should have done that. They are the place to get a new ECM already programmed with the OEM or RACE programs. I am waiting to see if it stalls with wire wiggle. | ||
| Tempest766 |
Harley butchered the seat a few years ago and replaced the ECM. Maybe they didn't butcher it enough? In any case, I'll have to check the connections as suggested. Just that ECM plugs would not be my first guess since that issue was supposedly addressed already. Are there any internal switches in the clutch, throttle, tranny, etc, that I should check to see if they are intermittent? | ||
| Natexlh1000 |
The clutch has a switch but that would only affect idle speed or the starter. | ||
| Desert_bird |
Check that little disposable thing-a-ma-jig behind the rear seat that cuts the motor when you drop the bike, or when your triple flip goes all funky. Ah shite, what's it called ...? You know ... Someone help me out here ...? They go bad. | ||
| Desert_bird |
Bank Angle Sensor! I had two go south. Just replaced them. One in the middle of the freakin Amazon in Brazil. Drag that was. Never went through the troubleshooting because seemed to be the problem. Similar symptoms: Everything is fine one minute ,then sudden power down. Flipped ignition switch off and on and she'd start up and run just fine for a while, the bam - sudden death again. Now mine has the opposite problem: Never shuts the darn thing off and I've dropped her several times. Go figure. From the manual: Bank Angle Sensor The Bank Angle Sensor (BAS) operates from the ECM 5 volt sensor reference, and is grounded through the ECM on a common sensor ground circuit. Refer to Table 2-63. The BAS sends a signal to the ECM ranging from 0.24 - 3.4V under normal operating conditions. A signal between 3.4 - 4.79V will cause the ECM to turn off the engine. Once activated, the BAS causes the ECM to turn off the engine. When the vehicle is righted, the ignition must be switched OFF and then ON in order to restart the engine. If the signal from the BAS is below 0.24V or above 4.79V, the ECM sets a code. Refer to Table 2-62. DTC P1151 is set when the BAS output is shorted low (to ground); and P1152 is set when the BAS output is shorted high (to voltage). An open circuit output will act like a shorted high, and set DTC P1152. If a code occurs, the engine will continue to run. A tipped vehicle will not set a DTC. DTC CHECK ENGINE LAMP CODE DESCRIPTION P1151 44 Bank angle sensor shorted low P1152 44 Bank angle sensor shorted high or failed sensor Bank Angle Sensor Voltage MODE VOLTS Run mode 0.24-3.4 Disable mode 3.5-4.79 (Message edited by Desert_bird on February 23, 2017) | ||
| Tempest766 |
re: BAS - engine never actually shuts off. just drops back to idle RPM while accelerating. Letting off of throttle, then dropping to lower gear (usually) causes it to catch and accelerate again. The description says a triggered BAS shuts off the engine until the kill switch is cycled. Is that right? | ||
| Desert_bird |
No, you are right that a funky BAS will not affect engine revs. It will simply kill the motor. I mentioned the BAS only because you asked for " [a]ny thoughts on what could be causing the engine to [...] die under acceleration or while cruising (after warmed up)?" One less thing for you to troubleshoot! DB} | ||
| Scottykrein |
I had this and the cause was a bad TPS sensor. Only discovered it after hooking it up to ECM spy and watching the bar graph move as I twisted the throttle. The bad one was choppy and had a slight delay, the new sensor was smooth and had zero delay from twist to the graph. I THINK you can use the Ford mustang TPS on 08's... not sure. I couldn't on my 06. Just use the search for Ford TPS. | ||
| Mnrider |
Sounds like the fuel pump is going out. | ||
| Alchemy |
Had similar problem on my 2010 XB. Ran fine cold but as warmed up it would stumble or cut out. Thought it might be a faulty overtemp sensor. A drag to change but did not help. Could not see anything obviously wrong with the ECM. HD dealer said the ECMs on Buells fry over time from the temperatures. Not sure if it really is the temperature or the flexing under the seat or what but a new ECM was a 100% fix. YMMV of course. It is great when everything runs well again. | ||
| Twisteduly |
How is the battery? | ||
| Mark_weiss |
I ride in the Phoenix area. Year 'round. ECMs ('08 at least) can survive high heat. My seat was occasionally touching, as evidenced by marks on the connector, so I relocated the ECM. Faulty throttle position sensors can lie to the ECM, cause the ECM to think that the throttle is closed, and then the ECM switches to idle fuel and timing. | ||
| Gmaple |
I had similar symptoms with my 06, turned out to be the hose between the fuel pump and the pressure regulator. Pulled the fuel pump assembly and after inspection found the hose was cracked. | ||
| Tempest766 |
Unfortunately spring in February is over and it's too cold to work on it again. God, I hope it's not something like the fuel pump. I have not the tools, skill, or time to turn an engine...and I've had less than stellar experiences with the only local HD dealer who will service Buells. | ||
| Natexlh1000 |
You don't have to pull the engine to get at the fuel pump. You jack it's butt off the floor, remove the rear shock lower connection and push it out of the way. This allows the swingarm to go lower. The more I think about your symptoms, the more I'm thinking that there may be something wrong with your TPS. The TPS is just a potentiometer with three wires coming off. If one of the wires is broken or something, the computer would think you let go of the throttle and revert the bike to idle. | ||
| Etennuly |
I agree that the TPS is the cause at this point. The wires that run into them can get compromised, they are in a major heat zone. The insulation actually melted together on my "06's. Had to separate the wires and line them with heat shrink. | ||
| Tempest766 |
I do appreciate all the input, and am hoping that the solution turns out to be minimally painful. I will look at the TPS, and hopefully can figure out a way to remove and bench test it. I've got some things to look at when the weather allows me to get into my garage on a saturday afternoon...but feel free to keep the suggestions coming. | ||
| Mark_weiss |
TPS should be fairly easy to check with a multimeter, especially an analog meter. The resistance through the sensor should smoothly change as the throttle is moved. Even when the throttle blad is tapped, the sensor's resistance value should not falter. I don't know that a faulty but not broken sensor would trigger a fault code. BMW's could have a bad TPS and not trigger a code but would yelid an "improbable reading" indication on a printout. | ||
| Natexlh1000 |
Find the three wire connector that leads to your TPS and put a meter on it You don't need to tear apart the throttle body. Please examine this complex diagram:  Bear in mind that it's not going the full 0-5V since the butterfly only turns about 90 degrees. What the computer would see is above 0 and below 5. you unnastand? | ||
| Tempest766 |
Yeah. Once I get a cheap DArsonval meter I'll check the output while fidgeting with it to see if it has dead spots or loses contact under any pressure or torque. | ||
| Reepicheep |
An adequate DMM is dirt cheap these days. I think I got one for $1.50, or maybe free, with coupon from Harbor freight. Not great, but good enough for this. | ||
| Ourdee |
How much is a Ford TPS if one fits and what is it's part number? If it is under 20 bucks, I'd just swap it out. | ||
| Tempest766 |
Aftermarket ford mustang 93 TPS is about 50 bucks from web search. Will depend upon whether the butterfly shaft tabs are at 6 and 12 or at 2 and 8, when I pull it to inspect. | ||
| Etennuly |
When you do a TPS reset make sure you clean the edge of the throttle plate. Run your finger on the edge, if it feels rough it needs cleaned to close completely in the bore for a true 0 reading. Also when you get to that point warm the engine before doing a final TPS set. Cold will give you a false reading. | ||
| Ourdee |
I use carb cleaner on Q-tips held in forceps to clean the edge. | ||
| Tempest766 |
re - TPS cost $50 bucks? .... If only... the 08 and later specific one was a friggin $120 bucks on craigslist. the 3rd party duralite part that is "rumored" to work was over 90 mail order. Those prices are pure robbery for something that is simply a pot, wires, and a plug. I can only imagine what the HD folks will be charging, if even available. | ||
| Natexlh1000 |
Well verify it's bad first! |
