xb12r cuts out above 1/4 throttle

I have an 04 xb12r that idles nice, and takes fuel fine until above 1/4 throttle. Seems throttle dependent, as I can let it rev pretty well by turning the throttle slowly. I Did the Ecm reset twice, and the tps seems to follow the throttle opening fine. replaced the fuel sock, and filter, and the pump sounds good. With ecm spy (mono) running, I see the o2 sensor go down to single digits when snapping the throttle open, but as soon as I let off it resumes running clean. No rich ,or lean condition. It just simply stops running when opening past the 1/4 throttle point, then resumes running fine when I let off just like a light switch. I Will check fuel pressure, and for spark at throttle opening next. I have heard that the ignition pickup can cause this issue. Does it act that that dramatic, or spit and sputter when that unit goes bad?

This sounds like a throttle position sensor issue. Are you sure you have followed the correct procedures for resetting the TPS?
Also sounds like issues members have dealt with after removing the velocity stack and not installing it correctly. If youve been under the air box recently go back and insure the velocity stack is installed correctly.

A little history and current mileage of your bike also helps with attempting to diagnose issue over the net. Let us know mileage and mods that have been done to the bike.

You mentioned “resetting the ecm”?? What do you mean by this? Have you recently reprogrammed the ecm?

You also mentioned the “ignition pick up”, are you talking about the cam position sensor(CPS)? I don’t believe that sensor would be directly effected by throttle position. That sensor sets the timing for your ignition system. The CPS basically tells the ecm when to fire off the spark plugs. At least that’s my layman’s interpretation of it. It’s also not that common for that sensor to go out.

If you’ve been twisting that throttle on a static bike(not under load/riding) you might want to check your plugs. They are probably fouled and only making things worse.

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Originally Posted by Chicknstripn

This sounds like a throttle position sensor issue. Are you sure you have followed the correct procedures for resetting the TPS?
Also sounds like issues members have dealt with after removing the velocity stack and not installing it correctly. If youve been under the air box recently go back and insure the velocity stack is installed correctly.

A little history and current mileage of your bike also helps with attempting to diagnose issue over the net. Let us know mileage and mods that have been done to the bike.

You mentioned “resetting the ecm”?? What do you mean by this? Have you recently reprogrammed the ecm?

You also mentioned the “ignition pick up”, are you talking about the cam position sensor(CPS)? I don’t believe that sensor would be directly effected by throttle position. That sensor sets the timing for your ignition system. The CPS basically tells the ecm when to fire off the spark plugs. At least that’s my layman’s interpretation of it. It’s also not that common for that sensor to go out.

If you’ve been twisting that throttle on a static bike(not under load/riding) you might want to check your plugs. They are probably fouled and only making things worse.

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Just found it today. As soon as I tried the bike without the airbox cover it was fine. It was the velocity stack that was not all the way down. I mistakenly said in the original post that the Ecm was reset. I meant the TPS. I still do not understand why it did not sound rich after letting off the throttle, since it was being choked for air when on the gas. It would resume running perfectly immediately. Oh well, runs good now. Thanks for the help.