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One TBW issue isolated

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Old Jul 6, 2009 | 07:58 PM
  #1  
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Default One TBW issue isolated

For you folks with Throttle By Wire touring bikes, here is a cut and pasted post from Harley Tech Talk. The issue is VERY similar to the broken speedo wires inside the harness issue many others including me have experienced.





Hello everyone,

Bike is a 2008 Ultra Classic, 61k miles.

Last Wednesday I was pulling into my parking space at work, I had to back in where I normally pull a small U turn, when I turned my bars all the way to the right and then back to center my throttle blipped. Thinking that that was a strange thing I rolled the bars back to the right then returned to center and the throttle blipped again. Nothing major but it was noticeable that something was wrong.

The next day I was at the dealer to replace a tire, I showed the service manager the problem by moving the bars from right back to center. The throttle blipped again, and he acknowledged that something was wrong. After the tire was replaced they started moving the bars back and forth and got the throttle to blip several times, but they said because they didn't install the heated grips that it was something they would have to charge me to check.

Being cheap and after talking to the mechanic I figured that it was probably a wiring problem and took the bike home to check. He was thinking that where the wires come out of the handle bars under the fairing was where the problem might be.

I got the bike home and removed the fairing and radio to allow easier access to wires, and everything in the fairing looked good, nothing frayed no cuts. So started wiggling wires from the steering head and the throttle revved up again. I couldn't get it to happen again, so I removed all the wire plugs and pulled all the wiring in the fairing that comes from the right side of the frame and removed the wiring clamp to allow room to get at the harness. I found everything looked good. So thinking the problem was in the wires going into the main harness on the right side I cut and opened the sheath for the drive by wire harness. Once I had that harness opened I took each wire one at a time and started to pull on each wire. Again everything was fine. So I ran all the wires back into the fairing and plugged everything back together and started the bike.

With the wires all loose and open I started wiggling again, this time the throttle went full wide open and stayed there, I had to reach up and turn off the bike. Now I knew something was very wrong, I loosened all the connectors in the fairing and pulled the wires back out and pushed the main harness sheath back as far as I could.

I found tie wrap right under the main harness where all the wires came together. I cut the tie wrap, isolated the throttle wires and pulled on each one again. This time though, I found 2 wires broken inside the insulation. I spliced them back together and soldered them and put some heat shrink tube on each one. I put all the wires back into the fairing and started the bike, it ran fine.

Took it on a long ride Friday and everything seemed fine.

Just wanted this to be a heads up for everyone with the drive by wire. The wires were broken right where the tie wrap was, the tie wrap pinched them and then with the little bit of movement everytime the bars are moved full travel was enough to break them over time.

Ride safe,

Frank
 
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Old Jul 6, 2009 | 08:26 PM
  #2  
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I got stranded in Gettysburg - they replaced the twist grip sensor twice - no dice. When I trailered the bike back to FL they isolated it to two broken wires in the main harness - under the insulation - sounds like the same issue. Perhaps they had an issue with the initial install of the main harness. I just hope the solder job holds.
 
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Old Jul 6, 2009 | 08:30 PM
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Thanks for the info.
 
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Old Jul 6, 2009 | 08:33 PM
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Pics?
 
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Old Jul 6, 2009 | 08:37 PM
  #5  
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2008 SG for me 34k miles and already a new wiring harness after many new twist grips and a couple of induction modules

after replacing the wiring harness it's happened again

it sucks cause im scared to go on any long trips call HD and they say they will keep fixing it
 
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Old Jul 6, 2009 | 08:39 PM
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Originally Posted by Paniolo
For you folks with Throttle By Wire touring bikes, here is a cut and pasted post from Harley Tech Talk. The issue is VERY similar to the broken speedo wires inside the harness issue many others including me have experienced.





Hello everyone,

Bike is a 2008 Ultra Classic, 61k miles.

Last Wednesday I was pulling into my parking space at work, I had to back in where I normally pull a small U turn, when I turned my bars all the way to the right and then back to center my throttle blipped. Thinking that that was a strange thing I rolled the bars back to the right then returned to center and the throttle blipped again. Nothing major but it was noticeable that something was wrong.

The next day I was at the dealer to replace a tire, I showed the service manager the problem by moving the bars from right back to center. The throttle blipped again, and he acknowledged that something was wrong. After the tire was replaced they started moving the bars back and forth and got the throttle to blip several times, but they said because they didn't install the heated grips that it was something they would have to charge me to check.

Being cheap and after talking to the mechanic I figured that it was probably a wiring problem and took the bike home to check. He was thinking that where the wires come out of the handle bars under the fairing was where the problem might be.

I got the bike home and removed the fairing and radio to allow easier access to wires, and everything in the fairing looked good, nothing frayed no cuts. So started wiggling wires from the steering head and the throttle revved up again. I couldn't get it to happen again, so I removed all the wire plugs and pulled all the wiring in the fairing that comes from the right side of the frame and removed the wiring clamp to allow room to get at the harness. I found everything looked good. So thinking the problem was in the wires going into the main harness on the right side I cut and opened the sheath for the drive by wire harness. Once I had that harness opened I took each wire one at a time and started to pull on each wire. Again everything was fine. So I ran all the wires back into the fairing and plugged everything back together and started the bike.

With the wires all loose and open I started wiggling again, this time the throttle went full wide open and stayed there, I had to reach up and turn off the bike. Now I knew something was very wrong, I loosened all the connectors in the fairing and pulled the wires back out and pushed the main harness sheath back as far as I could.

I found tie wrap right under the main harness where all the wires came together. I cut the tie wrap, isolated the throttle wires and pulled on each one again. This time though, I found 2 wires broken inside the insulation. I spliced them back together and soldered them and put some heat shrink tube on each one. I put all the wires back into the fairing and started the bike, it ran fine.

Took it on a long ride Friday and everything seemed fine.

Just wanted this to be a heads up for everyone with the drive by wire. The wires were broken right where the tie wrap was, the tie wrap pinched them and then with the little bit of movement everytime the bars are moved full travel was enough to break them over time.

Ride safe,

Frank
I call bullshit. I want to see the original paperwork on this. Drive by wire doesn't use resistance, it uses inductance. If the wires pulled out the circuit would be open and no current would flow at all. The throttle wouldn't work AT ALL, like these other guys have.

Nice try.
 
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Old Jul 6, 2009 | 08:42 PM
  #7  
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Originally Posted by ftanner
I call bullshit. I want to see the original paperwork on this. Drive by wire doesn't use resistance, it uses inductance. If the wires pulled out the circuit would be open and no current would flow at all. The throttle wouldn't work AT ALL, like these other guys have.

Nice try.
Originally I had 40% throttle (apparently there is a back sensor that operates in limp mode). However, eventually it went to no throttle. I guess I could have ridden the 'friction zone' all the way home from PA - would have made for an interesting 1000 miles.
 
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Old Jul 6, 2009 | 08:51 PM
  #8  
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Originally Posted by ftanner
I call bullshit. I want to see the original paperwork on this. Drive by wire doesn't use resistance, it uses inductance. If the wires pulled out the circuit would be open and no current would flow at all. The throttle wouldn't work AT ALL, like these other guys have.

Nice try.
Ftanner,

You are welcome to go over to Harley Tech Talk and throughly explain your doubts to the orgiinal poster. With your level of expertise and knowlege of these things perhaps you can help these folks diagnose and further troubleshoot the problem so they no longer make nonsensical postings I'm sure they would welcome any help.
 
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Old Sep 4, 2013 | 05:02 PM
  #9  
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I just created a thread a couple days ago on this subject. I had done searches but this didn't come up for some reason. Today my issue got a lot worse and I did a search on how TBW works so I know where to look. Then this came up. Main harness at the neck is where I will start. Pulling internal wires is a last resort.
 
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Old Sep 4, 2013 | 07:23 PM
  #10  
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From what I've seen of harness' in different vehicle applications it seems the assemblers install harness in a manner we at the boat factory call "banjo tight". Knowing an assembly line gives you a limited time to install, the QC dept. should look at this and give what we call "a service loop" so the wires aren't the constantly being pulled/stretched to the point of failure.
 
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