Rough Idle

Kkyyllee10 · Jul 30, 2023

A few months ago I couldn't get my 2008 xb12r to start. Reached out and here and got recommended I change the fuel pump. Changed it with the kit from aagaaurd, put it back together fired right up checked fuel pressure it was at 49psi. Now I could start to see what my problem that parked the bike which was not charging. Solved that by getting a new regulator and now it charges fine. My current problem is it runs horrible at low speed and idle. Will die once and awhile on idle and at 20 mph and under it is really rough and with out touching the throttle bike will change rmp. Once I start getting the bike up to speed no issues runs like a dream. I do have a buell thooth and reading from revision moto I did set both AFV's to 100% and TSP reset. So I got the stock tune from them and put that on the bike thinking it would help nothing. To my knowledge it has only had the stock tune and the bike is bone stock. Also bike has no error codes. A few times I have started it in the garage and my eyes start to water and it smells weird so idk if its running lean or rich. The gas is only 2 months old and is premium. Any ideas on what is causing this did I install something wrong in the fuel pump? Thanks in advance

Barrett · Jul 30, 2023

Kkyyllee10 said:
A few months ago I couldn't get my 2008 xb12r to start. Reached out and here and got recommended I change the fuel pump. Changed it with the kit from aagaaurd, put it back together fired right up checked fuel pressure it was at 49psi. Now I could start to see what my problem that parked the bike which was not charging. Solved that by getting a new regulator and now it charges fine. My current problem is it runs horrible at low speed and idle. Will die once and awhile on idle and at 20 mph and under it is really rough and with out touching the throttle bike will change rmp. Once I start getting the bike up to speed no issues runs like a dream. I do have a buell thooth and reading from revision moto I did set both AFV's to 100% and TSP reset. So I got the stock tune from them and put that on the bike thinking it would help nothing. To my knowledge it has only had the stock tune and the bike is bone stock. Also bike has no error codes. A few times I have started it in the garage and my eyes start to water and it smells weird so idk if its running lean or rich. The gas is only 2 months old and is premium. Any ideas on what is causing this did I install something wrong in the fuel pump? Thanks in advance

A few times I have started it in the garage and my eyes start to water and it smells weird so idk if its running lean or rich.

Rich

So I got the stock tune from them and put that on the bike thinking it would help nothing.

Corrupted file installed

Cooter · Jul 30, 2023

I agree with Barrett that your eyes watering in the garage is rich. Buell XB's have a very rich and very long cold start cycle, so if you are starting it cold in a closed area, it will reek of unburned fuel. So might be normal? Might be an issue? We'll see...

What is your AFV right now? That will tell you if the ECM is trying to compensate for something after you switched it to 100. You can only adjust the rear BTW. You don't have a front AFV adjustment on that bike unless it was modified.

What is your idle speed? Should be 1050-1100.

'08-up TPS re-set is a simple job of twisting the throttle. Are you doing it that way?

Kkyyllee10 · Jul 31, 2023

Cooter said:
I agree with Barrett that your eyes watering in the garage is rich. Buell XB's have a very rich and very long cold start cycle, so if you are starting it cold in a closed area, it will reek of unburned fuel. So might be normal? Might be an issue? We'll see...

What is your AFV right now? That will tell you if the ECM is trying to compensate for something after you switched it to 100. You can only adjust the rear BTW. You don't have a front AFV adjustment on that bike unless it was modified.

What is your idle speed? Should be 1050-1100.

'08-up TPS re-set is a simple job of twisting the throttle. Are you doing it that way?

AFV still is at 100 for max and minimum does it need to drive or run more before it will change. With live data up just shows 100.

It was idling at about 1000 before but after the tune took its not steady and keeps jumping any where between 1k to 2.5k.

Yes doing the TPS 3 times with the throttle with the kill switch in the the POS

Cooter · Jul 31, 2023

So you didn't 'set the AFV to 100'... you locked the AFV in place by changing the Max and Min settings. Thats different. It won't change now because you set the max and min settings to 100.

With those changes you made, the ECM is unable to do what it needs to do. It is unable to adjust for the best running. Normally it does that by reading whats coming out of the engine (O2 sensor) and then adjusting to what goes in, many times a second. By doing that to the AFV limits, what you have created is a carburetor. Can it work? Sure. Is it ignoring 3 DECADES of technology that make it more rideable, more powerful, and better emissions? Yes.

It is also unable to adjust for any elevation changes (like a carburetor also cannot) so now you'll need to add a previously un-needed sensor (Baro sensor) so the ECM can at least adjust for that.

IMO, put your old tune back in (I sure hope you saved it), put the AFV max at 120, min at 80, TPS re-set one more time, not sure what you mean here:

Kkyyllee10 said:
with the kill switch in the the POS

but re-read the manual instructions and do it one step at a time, carefully.

and then report how it runs and idles.

Kkyyllee10 · Aug 3, 2023

So I put back on the original tune I did have it saved, did tps re set. Didn't touch anything else still is idling from 1200 to 2k just won't stay at a certain speed. I re downloaded the stock tune I got from revision in my email. Put that back on same thing tps re set and that was it. Same outcome on idle

Kurlon · Aug 3, 2023

When you let the throttle snap closed, is there free play in the grip?

Rough Idle

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