Very hard cold start on a 2012 RT

[DROOT153718]

Roger thanks for the numbers. 204 out of 255 is close to all the way open at 40*f. It dropped to 165 the moment the engine caught. The steppers cracked the throttle for you.

One 1200 warm idle was 90 another warm was 125. Both in range, but you can see bikes are different even though in the middle of the scale.



I went out today, threw the trickle charger on the bike. Later I turned on the key, pushed the button. It fired after 3 compression strokes, went to 1500 RPM then died in about 3 seconds. I pushed the button again with the throttle cracked. 4 or 5 compression strokes it started up. I let go of the throttle, it idled at 1500 slowly dropping to 1250. I blipped the throttle a few times. It would not stall. The bike had been sitting about a month. (sad aint it?) The ambient temp on the bike was flashing 26.6* f.

SO I answered my question. The bike once started had a desired RPM of 1500. As it warmed up, the desired RPM went down. I did not have time to warm it all the way up which I will do tomorrow night. Its snowing and blowing enough its hard to drive a car today.

So I think there is something wrong with the offending bike. Once started it should have maintained a fast idle.

NOW we need to know where the stepper motors are when the bike is started cold.

Thanks for the fun, I have not heard my bike run in a month. It got ME fired up. All I have to do is wait a couple more months so I can ride it.

David

 

[roger 04 rt]

What about elevation?
The two places I recall having the problem were Utah, 7000 feet, and Jackson Wy, 6200 feet.
It's never cold enough here to do it.
Even to see the rams on those iac motors, I have to dig fairly deep into the bike, don't I.
I'm going to look further when I change the trans oil and tires in 1000 miles.
dc

Don's photos and cleaning routine sounds interesting. Really to know what's happening with your bike during cold start you need a GS-911 connected and logging realtime values. Without that it's educated guess work.

The BMSK reads barometric pressure, same as the Motronic. Therefore unless the iac motors run out of range ielevatuon shouldn't matter.

 

[roger 04 rt]

From the GS-911 web site.


IAC - Idle Actuator Calibration for all CAN-bus based BMW motorcycles


What models is it used on?
All CAN-bus based F-, K- & R-Series motorcycles... This function was available for the R-Series since their inception in 2004, but BWM recently (early 2009) qualified and introduced it for both F- and K-Series models too...

When do I need to use it...?
You typically run the Idle Actuator Calibration function when the motorcycle is suffering from poor idle... It is also recommended to run this function after removing and/or replacing any of the Idle Actuators...

What does Idle Actuator Calibration do?
Below is a quote from BMW's Release News for the CD25/CIP13, released early 2009:
"Symptom poor idling: activate idle-speed actuator adjustment
The toolbox for BMS-KP control unit functions offers for all CAN bus models with poor idling the opportunity to carry out an idle-speed actuator adjustment. This adjustment was previously only available to boxer models and has now also been approved for the K4x and K7x Series.

Here, both idle-speed actuators of the K2x models are moved by the engine electronics control unit against the lower stop in the throttle valve assembly, i.e. the air passage is closed. On K4x and K7x models the idle-speed actuator is moved to the stop in the intake silencer. This operation enables the control unit to determine and relearn the exact position of the stepping motor in the idle-speed actuator.

The aim is - in the event of a customer complaint - first to carry out an adjustment without disassembling or replacing the component (duration < 1min) in order to check the idling immediately after a test ride."

You can do this with your GS-911 !
We introduced the Idle Actuator Calibration function in our first Beta of 2009 where it covered the R-Series models. Since the 906 Beta release, it also covers the F- and K-Series models too!

How do the Idle Actuators work, and why do they need calibration - Stephan's short version...
The IA is a stepper motor... these stepper motors have NO position feedback... i.e. there is no way for the ECU to know exactly where the IA is... the ECU starts off at what it assumes is a known position for the IA... and then as it does its work, tells it to move X steps in one direction or Y steps into another... However, as time goes by the IA does not always move the amount of steps it is commanded to move by the ECU (this could be due to filth, friction, reaching the stop etc.)... hence, as time goes on, the ECU "thinks" an IA is at a specific position, when in reality it is in a completely different position... in reality the ECU has lost synchronization with the stepper(s).

The solution is the Idle Actuator Calibration... in the R-series, the IA's are moved into the completely closed position (several times) and the ECU, then uses this as it's reference for "closed"... It now has a known reference point from which to command the steppers again...

The IA's in the R-series work similar to the idle screw in the R1150 and R1100 engines... in the throttle body of the R1200 models, there is still an idle-air bypass channel, and the IA is of the "plunger"-type... i.e. it moves perpendicular to the idle-air channel, causing more or less of an obstruction in this channel, and thus controlling the amount of air that is passed through this channel...

hope this helps!


Some more reading on the Idle Actuators and Engine synchronizing
A BMWSportTouring thread discussing throttle body sync

 

[deilenberger]

Even to see the rams on those iac motors, I have to dig fairly deep into the bike, don't I.
I'm going to look further when I change the trans oil and tires in 1000 miles.
dc

David,

Assuming you mean the idle-control steppers - without knowing what model/year hex/camhead you own (that might be useful info to put in your sig) I can't answer that question. On an R1200R - they stick out in the wind on the top of the throttle-bodies. It might take all of 2 minutes to remove one.

 

[roamingbeemer]

When I start my 2011 Camhead in cooler to cold temps I have to crack the throttle maybe 1/4 to 1/3 inch. I just accepted this as normal. When I do not it will immediately stall or not start at all. I can not remember exactly since I always crack it now. My house is 6000 feet MSL and it is the only FI bike I have had to do that with.

After reading this I guess it is not a totally accepted practice. Thx for the information.

 

[marchyman]

After reading this I guess it is not a totally accepted practice. Thx for the information.

The procedure recommended in the BMW riders manual is not totally accepted practice?

 

[roamingbeemer]

The procedure recommended in the BMW riders manual is not totally accepted practice?

I guess I am caught not checking the manual. This thread seemed to suggest it should not be necessary.

But you should know a forum takes precedence over manuals...

I retread the beginning of the thread and saw it about much more than cracking the throttle. Me bad...

 

[David13]

The procedure recommended in the book is totally accepted practice, to BMW, I think, and that is why they put it in the manual. As they had done away with the fast idle lever.
However, the issue still remains.
Is the hard start, or crack throttle start usual and ordinary, or is something wrong with the bike that can and should be fixed.
There remains some question about that.
Some more words from Santa Cruz:

"Stepper motor same as IAC.
You (we) have two of them, one each TB.
I believe IAC values on GS911 are showed in percentage, 0-100%. I may be wrong though.

If in %, they should ideally be around 13-23% warm idle.
They should be above 40, maybe 50% during cold-start.
ECM defaults them open whenever throttle is opened so idle is high when throttle is closed to prevent stalling.
So then, warm engine, say 20% IAC at idle, crack throttle to 2500 RPM, IAC counts should instantly rise to, say, 55%.
Once throttle closed, IAC counts should progressively drop with RPM as ECM reduces idle speed back to normal.
If cold-start idle is labored and IAC control is the problem, IAC values would be very high--above 70%--reflecting inability to achieve the necessary air flow to match idle speed to conditions.

I would be most curious to view your data David. Others are concurring that your cold-start issue is not normal, and the causal condition should be pretty easy to spot in your data-stream. Even warmed up, but preferably cold to start. Example:

If your issue is caused by restricted intake airflow, your warm idle IAC counts would reflect this restriction with high values, above 30 or 40%."

And:

"The fast idle lever was removed because two IAC valves were added to a much more advanced engine control system.

You should not be having that problem."

And:

"Ahh, elevation...

Hard starting and excessive rich running at elevation is a common issue overcome by EFI, but the ECM needs to know you're at higher elevation. Next time, run WFO at high elevation before you shut down, then on next startup, cycle key on and off twice with five second intervals and try it."

dc

 

[storman113]

Just had bike in for new rear tire (PR3) and new brake pads on the front.

Has been hard to start recently especially in the cold weather here(central Oregon).

Mechanic reported he repositioned the main battery ground to butt against the battery post. I have added multiple grounds on the post over time for several items. I had inadvertently positioned one of them between the main post and the main ground for the system (reduced contact patch for max conduction). Mechanic stated that its a small thing, but when cold or weak battery, that small thing can become a real big thing. Unit starts easy now.