A2B Metro throttle issue.... bike taking off on its own.

[adh247]

I'm curious if anybody else has had this issue... Lately my throttle has a mind of its own. Three or four times now, If I park it and forget to turn the key off, the bike will just randomly try to take off!

I park it inside and twice now I've come into the room and noticed my bike slammed against a wall and my cat hiding under the couch. It's also done it once when I got off the bike.

I've also noticed that twice now when I go to take off on my journey, I'll notice nothing happens when I turn the throttle, but if I turn the throttle back and forth a little, then it will work.

Could this most likely be dirty throttle contacts? Seeing that I can no longer order a new one, how would I go about taking the throttle control off/apart so that I can clean it internally.

Any help would be greatly appreciated.

 

[Bandit1961]

Good question but unfortunately I don't have the answer, but similar things have happened to me when starting. There's many an A2B'er on here so hopefully some solutions will pop up.

 

[rafalg]

Maybe don't leave it unattended in the room if problem is not resolved . Who knows, maybe it would turn on and overheat/catch fire.

 

[adh247]

Maybe don't leave it unattended in the room if problem is not resolved . Who knows, maybe it would turn on and overheat/catch fire.

Thank you for your obvious insight.

 

[calab]

I'm curious if anybody else has had this issue... Lately my throttle has a mind of its own. Three or four times now, If I park it and forget to turn the key off, the bike will just randomly try to take off!

I park it inside and twice now I've come into the room and noticed my bike slammed against a wall and my cat hiding under the couch. It's also done it once when I got off the bike.

I've also noticed that twice now when I go to take off on my journey, I'll notice nothing happens when I turn the throttle, but if I turn the throttle back and forth a little, then it will work.

Could this most likely be dirty throttle contacts? Seeing that I can no longer order a new one, how would I go about taking the throttle control off/apart so that I can clean it internally.

Any help would be greatly appreciated.

TS throttle or get a new throttle. Be sure you take pictures, be sure you know what to buy, how many wires is the throttle? would a generic throttle work is the question on a a2b metro.

Maybe the ignition wire is always on, do a switch a rocker or a keyed switch.

Loose wires of generic non a2b controllers might touch by accident, like the Learn wires, usually white but not always. Labels fade, I take a picture of my controllers wires with labels clearly visibile, and add my own text to the wires to label them on the picture itself and save it then print it out and throw the sheet in my ebike folders, its saved me so many times. But when it comes to troubleshooting, pictures help. Pictures help with better responses on forums, so appreciated. Multiple pictures better, a whole bike picture is nice. That throttle looks like a standard throttle, with a switch of some sorts.

Stock controller, a2b metro?

 

[amberwolf]

The normal cause of throttle runaway is a broken ground wire anywhere between the sensor inside the throttle all the way to the PCB inside the controller. Usually the problem is at the connector somewhere, or where the cable exits the throttle or enters the controller (from bending).

If the ground fails, there's no reference for the signal voltage, the current path changes, and the controller sees full voltage on that signal. Some controllers have a safety for this that prevents operation above the expected max throttle voltage, most don't--so those just go VROOOOOM when it happens.


The problem of throttle not working without moving it around probably points to the cable exit of the throttle housing, or something inside the throttle wiring itself.

Another issue that could cause this (but doesn't usually cause the other intermittently), is a loose magnet that gets moved around from vibration or throttle body movement. Some throttles use two (or more) magnets at either end of the throttle rotation arc, that have to be specifically placed and oriented to get the sensor to output the right voltage at the right time--a loose magnet that has moved from the correct spot can cause what you see. Some use a single curved magnet over the entire arc, and those don't normally fail this way.


AFAIK the A2B uses a hall throttle, so there aren't any contacts inside it to clean or go bad.

If yours has a potentiometer throttle with a contact problem inside the pot, then replacing the pot would be the only confident option (because it's not the contacts that fail, it's the resistive ribbon that wears at various points; cleanings or repositionings of the wiper / ribbon may temporarily fix it but it may not be reliable).

 

[adh247]

I have rode this A2B Metro.for.a.few years now and has been pretty reliable for me. I give it the proper maintenance and keep it clean.

However about a month ago, The bike would start making this noise and/or would jump forward every.time I turn the key off (posted in the video)

I know it's not the battery because I just put in a new one and it still does it.

My next thought was maybe it's the relays, but the A&B relays both work fine.

So now I'm kind of clueless about what is causing it.

That being said, the bike rides perfectly normal otherwise, so if anyone has any ideas please let me know.

 

[adh247]

Thank you for the very detailed answer!

I have the factory twist throttle on the right handlebar. I found this in the manual but I'm still not sure what to do now because I don't know which aftermarket throttles are compatible with my bike. Does the throttle have a cable that goes down the frame with a connector on the end? I'm going to try to follow the cables down to look for any loose connections. I feel clueless in regards to hall related things and/or what it means.

I'm not sure if this is relevant but I used to be able to hold the throttle all the back without any issues, now I've noticed that i cant go full throttle for more than like 5 seconds (even with the new battery) before the bike shuts off and I have to turn it off and back on again for it to work again.

I attached some pictures of the bottom side of the battery frame where all the wires go. I'm not sure if it's a BMS or a controller or what.

 

[adh247]

@amberwolf that is some very helpful advice. it makes sense that it might be a ground. So there's no way take it apart and clean it etc? I really like this throttle so I'm gonna have to look around for someone that might have one.

Do you think it might be causing this problem as well? I'm kinda stumped on this one. it doesn't affect the ride 9r anything, but I can't figure out what this could be.

p.s. yes the throttle cable has a plug on it that goes inside the frame to where the connections are.

 

[adh247]

I finally got around to fixing the problem of throttle run away, as well as the problem that caused my bike to lurch forward after turning the bike off.

It was the throttle after all. I got a new throttle that looks just like the original except it has no SOC or led indicators.

First pic is of old throttle, Second pic is the new one.
Thanks for the help fixing this. Especially Amberwolf!.