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Discussion Starter #1
On the first ride of the day and with the engine warmed up when I shift into 2d gear, I experience stumbling (for a lack of a better description) as I open the throttle. And I don't mean wide open either. Then after shifting into the higher gears it's gone. At first I just chalked it up to the flash as nothing is perfect. And yes I've cleaned the throttle body. And it doesn't help. There aren't any vacuum hoses off or leaking either. I finally discovered while cleaning the throttle body that as I slowly start to open the throttle slowly the butterflies are fluttering. Quickly slightly closing and they are opening. They aren't opening smoothly. If I wrap the throttle open and closed a couple times, then slowly open the throttle they open smoothly. So, now when I first turn the switch on I open and close the throttle a couple times and don't experience the stumbling as I start riding. So, with great thought and pondering I summarized that it was probably the TPS. I'll just order one and replace it. Well, put a dress on me, slap me around and call me Susan, can't do that. You have to buy the throttle body to get a TPS as they are paired together at the factory. Can't even remove the TPS without taking the throttle body off. I did pull the connector and cleaned the contacts just in case the problem could be there. It wasn't. So, I guess I'm now asking the great minds of members here, what's your guess?
 

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Discussion Starter #3
I would try lubing the cables. I use boesheild.
I hope you know that the throttle cables aren't directly connected to the throttle plates (butterflies if you will). All they do is rotate the TPS that sends a signal to the ECU that in turn sends a signal back to the electric motor on the throttle body to position the throttle plates accordingly. As far as dirty cables go, they would have to be actually pinched to effect anything. The throttle return spring is strong enough to overcome any resistance dirty cables could possibly give. I know no one wants to here any derogatory comments about the "flash", but nothing's perfect. Only three possible things that could be causing this. The TPS, the ECU or the electric motor on the throttle body. I suspect the TPS. Just cant replace it.:crying2:
 

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..Only three possible things that could be causing this. The TPS, the ECU or the electric motor on the throttle body. I suspect the TPS. Just cant replace it.:crying2:
Are you getting a code 11? Measure the voltages as shown. I bet it is your flash... or... some other sensor like water temp, influencing your ECU.

Vflash.jpg
 

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Discussion Starter #5
Yeah, forget to mention, no code. That would narrow it down considerably. I don't believe it's some sensor somewhere in the system though. I've watched the throttle plates opening erratically through about 1/4 throttle movement slowly, with the bike cold. After opening and closing the throttle quickly a couple times and watching them again while slowing opening the throttle, they act normal. All this while the bike is cold. After it's been running everything operates normally. It only happens as I move out, shift into second and a little in third. After that everything is fine. I've been thinking about watching maybe Ebay or somewhere for an ECU that's reasonable and swapping mine out and see what happens. Might try and take a video and posting it. That's of course if I can figure out how to post it.
 

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I hope you know that the throttle cables aren't directly connected to the throttle plates (butterflies if you will).
No I was not aware of this. Having just bought a '12 Nomad I am still on the steep part of the learning curve. I am of the belief that when trouble shooting/repairing a problem whose cause I am not sure of to do the easy and cheapest actions first. I also feel that more problems are of a mechanical issue rather than electronic. What led me to my suggestion to lube the cables was your comment, "They aren't opening smoothly. If I wrap the throttle open and closed a couple times, then slowly open the throttle they open smoothly. So, now when I first turn the switch on I open and close the throttle a couple times and don't experience the stumbling as I start riding." That sounded to me like a mechanical issue with the cables. When sitting for a while the cables would take a set and wrapping the throttle would free them up. Now might it be possible the tps would see the "jerky" motion of the cables as a signal and send it to the "butterflies"? I am not suggesting this IS the problem, it is probably not but it is a cheap and easy thing to try before replacing expensive bits. I am very interested as to the solution to this problem, I have not experienced it but if I do in the future it would be nice to know the cause.
Jim
 

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Discussion Starter #8
I agree. Before the days of all the electronics when computers took over, the cheep and easy fixes usually worked. When I start to move out I usually shift quickly into second. Don't get the big clunk that way. Then as I'm opening the throttle I get the stumbling. In the Carburetor days, the throttle cables were directly connected. Twist the throttle and the throttle plates open.
 

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Discussion Starter #10 (Edited)
Not a big problem and I'm not spending money on it. I've always found, this maybe just me that, if your looking for a needle in a haystack, it might be best to first know which haystack to look in. Not a real big problem as I said.:laugh2:
Those voltage readings could be meaningless if the TPS is sending the ECU erroneous data. Might lead you think the ECU is bad when it might just be the TPS. Would be nice to be able to change it.
 

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Not a big problem and I'm not spending money on it. I've always found, this maybe just me that, if your looking for a needle in a haystack, it might be best to first know which haystack to look in. Not a real big problem as I said.:laugh2:
Those voltage readings could be meaningless if the TPS is sending the ECU erroneous data. Might lead you think the ECU is bad when it might just be the TPS. Would be nice to be able to change it.
My 1700 vaquero did the same thing until it threw up a code which was throttle body sensor..i pulled off throttle body and ran throttle body cleaner over it and reinstalled throttlebody goodbye code no more fluttering..stay away from all gas containing ethanol when it burns its creates a film of varnish which seems to play havoc with sensors..hope this helps drive safe

Sent from my LG-H831 using Tapatalk
 

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Discussion Starter #12
Mine has never set a code. That's the biggest piece of the puzzle. I've cleaned them as you did several times. This time when I cleaned them I cleaned the air temp sensor and tried to spray some dry lube in the hinge points of the throttle plates. Fluttering is gone for now, not sure what did it. One piece of advice, don't open the throttle and stick your finger in past the plates, then close the throttle. They drive open and close by an electric motor.. Quite strong too, to say the least. But on the bright side, my finger will heal up in a few days. Finding Non-Ethonol gas here is easier said than done though it is around. I did notice on my rides in Canada it seemed to be more readily available, and, I've ridden from Cape Breton Island in Nova Scotia to Thunder Bay in Ontario. Some pretty riding I must say.
 

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This time when I cleaned them I cleaned the air temp sensor and tried to spray some dry lube in the hinge points of the throttle plates. Fluttering is gone for now, not sure what did it.
Thanks for the update! Do you feel confident one of these two things you did corrected the root cause of the problem? It would be nice to know if a cleaning and lube is the fix rather then having to replace parts.
Jim
 

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Discussion Starter #14
I'm not really sure. I would think the air sensor would cause an issue continually. The throttle plates are operated buy an electric motor. Maybe the cleaning, IDK. Head scratch-er, but for now no issue. If it comes back, I'll try just the lube and see what happens. Then just the cleaning. One thing at a time.
 
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