449 Secondary Butterfly TPS voltage

Does anyone know what the TPS voltage should be of the secondary, servo throttle butterfly at idle, or fully closed?

I'd like to better understand what voltage the ECU is aiming for under certain circumstances. When cold starting is the ECU moving the secondary to a certain position to achieve a particular primary opening voltage through the cam?

Any knowledge or info about what calibrations i can do with the secondary woiuld be greatly appreciated, or anyone who has a wonderfully running bike and can take some readings would also be a great help.

Why not just remove the secondary butterfly valve? mine seemed to run better without it!

I already have the butterfly removed, but the actuator and position sensor are still in the system, and on the other end of the spindle is still the small cam that can hold open the primary throttle butterfly a few degrees if it wants to. What I'm trying to understand is how to get that piece calibrated. As my bike is not that nice to ride just off idle, I'm looking for anything that might be causing incorrect fueling at the 0-5% throttle opening - if any of the fueling parameters are based on the secondary rather than the primary position sensor, then it's important that this is also correctly calibrated and positioned, as well as the primary (which I have reset and calibrated).

I agree the throttle response is lovely and snappy without the secondary, but for slow speed technical work in the 0-5% throttle opening range things are very snatchy so I'd be interested in putting the secondary back in, if it was all correctly calibrated, as I think that would smoothen out the opening.

I have the Full Akra Map (Map set 3) loaded onto my 2011 bike, which I managed through TuneECU, I can apply a further richening (akin to the Powercommander over-map) but I think I'd like to perform some O2/AFR tests first to see exactly how rich it is running- it smells like it's already running pretty rich...

You can definitely load maps to the 2011ecu, could even with the HST as I did it myself , not sure why we were it couldn't be done.

The secondary butterfly reading has no bearing on running, but regardless, it self calibrates each time it parks as it sweeps from zero to 100% and returns to the last idle position when the ignition is keyed off.
I do have a file on how to check the correct readings but the butterfly would need to be installed again.

I'm about to start fiddling with the maps just off idle myself with the TuneEcu, there's always been a dead spot there regardless of the original Map 2 or after the Akro Map upload.
Looking at the fuel cells in the 1-5% range, as the rpm increases, lots of the numbers in the tables don't increase as well....
It might also be the very flat ignition timing in the same area.
Hope this helps.
David.

With tuneECU you have FULL control of fuel injection pulse length under throttle control or inlet pressure control, plus the ignition timing and the switch points for the throttle vs inlet pressure injection control. You also have the ability to apply a PCV map. So basically, you can do it all.

My latest set of adjustments have been to reduce the advance in the 0-2000 rpm range which has made starting easier, specially when hot. I've also smoothed out the ignition curves through the range (only by adegree or two in most cases) and this has smoothed our things quite nicely for me.

I'll do some runs with the diagnostics showing so that I can get a full appreciation of different operating modes and then start looking at the fueling in any areas that are giving me problems, and also try to identify any glitches/lumps i feel that might be related to the F/I switching.

Yes, you can access both fuel and ignition tables and adjust cells.
I don't have PCV as you know, but I believe the developers were looking to, or have allowed the Hex maps from PCV to be added...
Haven't seen it, so you'd really need to check up on it yourself.

A word of caution ⚠
Always save your original fuel and timing map PRIOR to any adjustments, if it ends up messed up, you can then always revert to the original saved map.

That's what I've always wanted for my bike. As a mechanic who has used stand alone replacement ECUs for rallying, and knowing that the Keihin was flashable, I never liked the add-on systems.
I know it was the best solution at the time, but knew there was a better way available, shame it's taken till now for all the pieces to come together.

Best thing is now ALL owners have access to diagnosis data at the very least.

As mentioned in my message, I'll attach the secondary TPS base voltage test file to this post.


** "I'd like to better understand what voltage the ECU is aiming for under certain circumstances. When cold starting is the ECU moving the secondary to a certain position to achieve a particular primary opening voltage through the cam?" **

I'm not sure the ECU learns the TPS voltage as the engine idles, fair to say it might, but I'd expect that as you suggest, it would open the primary throttle via the secondary motor cam to a preset value.
As soon as the engine fires I expect the actual secondary shaft position would revert to whatever is required to maintain the target idle speed for the current engine temperature. (Not certain of this, call it an educated guess)

If you do make any adjustments to the setting, with the engine hot, disconnect the battery & drain power form the ECU by turning on the ignition & pressing start.
Reconnect the battery & start the engine without using any throttle, allow to idle for 5 mins or until the fan cycles to relearn idling.

Do you need to disconnect the lead to the secondary throttle motor first? To measure voltage you need the electrics powered up, the motor will try to put the valve into a specific position determined by the TPS. Trying to push the butterlfy against the motor could result in stripped gears I would have thought? That photo shows a throttle body on the bench, i.e. motor possibly not connected?

Once the motor has stopped moving, you can push gentle against the butterfly. The system has to be powered to get a reading.
I expect the BMW photo was done on a loose throttle body for visibility reasons.

This test and the reading really has no bearing whatsoever on the running of the engine if the butterfly is removed.
Really would only need to be checked/set if the drive motor was removed from the shaft.

So what I think you're saying is that you reckon that at the idle>off-idle end of travel the cam operates the primary throttle basis feedback from the primary TPS (eg at cold start it will hold the primary throttle open say 1%), but when the ECU wants to apply some secondary butterfly influence it moves and positions this butterfly basis the secondary TPS, which you can hear the ECU zero-ing/stroking/resetting during most power cycles...

That would make sense to me.

In effect yes.
The cam lifts and releases the primary shaft to meet the target idle speed.
As you say, at other times the secondary shaft (tries to, but often doesn't) match what the primary TPS position is.

I made this video of why we remove the butterfly, watch the marks on the shafts)

View: https://youtu.be/7Vn_9JxDOz8