Very hard cold start on a 2012 RT

[AjaxTheDog]

Problem solved! Not what I or anyone else suspected...

In the interim between my last post and now I also developed a leaking rear shock. Oil dripping onto the exhaust and smoking was...well, a smoking gun! Good thing because I might not have noticed otherwise. So I brought the bike to BMW of Denver on New Years eve for both this and the hard start issue. New rear strut was installed and they first diagnosed the hard start problem as being due to a questionable throttle valve switch PN 13547696412. They said that "...throttle position sensor ...was found to have an open position in the sweep." and replaced it. That helped but did not totally solve the problem so they swapped in a fuel pump electronics PN 16147720777 from another bike and this did solve the problem. I believe that is the injection fuel pump, which is not something I would have ever guessed. So anyway it took a couple of weeks but they did diagnose and solve my problem. I thought the bike ran fine before but now it is smooth as silk and seems to have more power. I am probably dreaming that but it definitely does idle more consistently, no hunt whatsoever, just thump-thump-thump. They were also trying to talk me into a new set of plugs (they said these were dirty) but since these only have 5K miles on them I declined. I may just put in a new set for the 18K mile service. The last thing they said was that the Odyssey battery I have does not seem to have a very good cold cranking output. I suspected this as the original battery just seemed stronger on a cold crank. Oh well, I guess as long as it fires up that doesn't matter so much to me, but I think when I do need a new battery I will go back to OEM.

Lastly I have to say that I really like BMW of Denver better than the other dealer in town, Foothills BMW. I had a similar starting problem on my old 07 RT and Foothills never did fix that, they just said I had to live with it. That and a few other semi bad experiences have turned me off to their service department, so I have decided that BMW of Denver is my new preferred dealer. They are very reasonable and seem to have better diagnostic skills that go beyond just plugging into the bike computer and looking for a code. I like that and plan to write them a thank you note for this very good experience.

So anyway, case happily closed! Thanks everyone for the suggestions, I appreciate the effort and advice.

 

[David13]

What I cannot understand is why someone would presume that there is some reason this bike will start in the cold without cranking the throttle.
Mine won't. And I know of quite a few others that won't.
And, tho' it seems more ignored than read, understood or believed, the book what comes with the bike says, 'crank the throttle.'.
So I certainly conclude that there is no cold start device on this bike.
I am also on a far wiser, more knowledgeable forum than this one, and no one, not one, nary one pundit has told me what nor where this cold start device is.
Then I could see if in fact, mine did fall off.

As to running down the battery, usually I remember from last winter after two or three crank and stalls.
In Jackson Wyoming, early one morning, September, pouring rain, dark from the rain clouds, it took me 5, no less than 5 crank and stalls before I remembered. Crank the throttle a bit. Immediate start up.
dc

 

[roger 04 rt]

I can't weigh in on whether to crack the throttle open or not on an R1200RT, but the R1150RT Rider's manual says to hold the fast idle lever full up (in effect cracking the throttle) when cold, till it starts, then relax it to the mid point. After meticulously going through fuel and ignition mine starts in under 2 seconds, mid point fast idle lever, down to 25F after an overnight cold-soak--no additional throttle required. The 1150 is very sensitive to battery condition during cold starting.

The cold start device is the BMSK itself. The chart below shows what the Motronic (and BMSK) does with injector pulse length and spark advance on a 50F morning. The simple explanation is that the BMSK holds the injectors open a long time for the first several rotations of the engine, gradually reducing the time as the engine warms.

 

[roger 04 rt]

... The last thing they said was that the Odyssey battery I have does not seem to have a very good cold cranking output. I suspected this as the original battery just seemed stronger on a cold crank. Oh well, I guess as long as it fires up that doesn't matter so much to me, but I think when I do need a new battery I will go back to OEM.

...

The internal voltage regulator on your alternator is set to charge GEL-type batteries. Because of that it slightly undercharges AGM-types like the Odyssey. I know the Odyssey batteries are a popular replacement and good quality, mine is the PC680. That said, it was being undercharged on mine. Oddly, BMW chose to put a higher voltage regulator on the R1200GSA, which is shipped with an AGM battery.

It seems a good decision to go back to GEL.
RB

 

[David13]

Roger
Two questions, first, does the BMSK run the 1150 the same as the 1200?
And secondly, if there is anything wrong with the BMSK operation, why does BMW still say crank the throttle?
Is there a fix? Or is it something not broke.
There is no fast idle lever on the 1200.
I use an oem battery. And where I had the issue was with a new battery (6 months old) after 3 solid all day rides.
I shouldn't say issue, because when I crank the throttle, like the book says, I have no problem.
However, there is no fast idle or run rich like on new cars. At least not sufficient to start on a cold day.
dc

 

[DROOT153718]

Rtfm

The manual says open the throttle a little when its really cold.

This is why.

Oil is thick, engine needs more gas AND air to fire up.

If you do not open the throttle a little, there is not enough gas or air to keep the bike running. It will fire then die because it is not making enough power to overcome the force required to turn the motor and transmission with the thick oil.

Opening the throttle adds more air and fuel. A total larger quantity of mixture so when it fires, it turns the engine more.

My dad had a 2 cylinder John Deere tractor. Early thirties vintage. To start it I had to turn the flywheel (about 2 feet across). It had a magneto so no matter how slow you turned it, the spark plug would fire. Both cylinders fired one after the other (like a Harley). It had a 180* crank so it turned once firing both cylinders then it had to turn one more full turn and compress the first cylinder before it fired again. In the winter at -20f, It would fire both cylinders, but not spin enough to fire them again because the oil was too thick. After 5 or 6 of these tries it would keep running. I plowed the driveway with that tractor until I went to college, then my dad bought a truck with a plow on it.

I hate to say this but synthetic oil IS thinner in really cold weather and will help the bike spin over easier and fire quicker from a cold start.

Opening the throttle a little like is says in the book should make the bike fire and keep running. This is what the cold start lever does on my R1100RT. It does not change the mixture, just opens the throttle a little.

Its 20*f here right now. I am going to let my bikes sleep today.

David

 

[David13]

Other David
That sounds like a John Deere 720. I know about them. Well, a little, anyway.
Choke or rich up the mixture, one way or another, vehicles usually address the issue.
Manual chokes used to quit working. A computer controlled in theory would not quit working.
The issue here is, does the BMW R1200RT have something to act like a choke? Is the computer supposed to do that? If it does not, why not? Is something wrong? Can something be fixed? Is it like putting a new choke on a car? A fix?
Why do you have to end up doing it manually? With the throttle?
dc

 

[David13]

Roger
This is somewhat addressed to your post.
This, from the wizard of Santa Cruz.

"Example: That waveform upload looks impressive, but Lambda is not a cold factor AT ALL because oxygen sensor will not function until warmed up--one minute to five minutes depending on application--and controls will be in Open Loop with enriched, cold-start default until it functions. Always, no exceptions, every feedbqck vehicle on earth.

The best input is reset adaptations with GS911. However, this should be combined with throttle body cleaning, plus TPS and TB synch too, then reset all fuel and idle control adaptations. Absent any other symptoms, codes or corrupted sensor data, this is the first thing a competent dealer tech would do too.

Poor cold idle is almost always due to IAC not being properly commanded. If adaptation does not cure this, it is possible IAC is struggling to open up proper in cold temps, a common condition on high-mileage units, not so common otherwise."

My bike has performed like this since new, or since my purchase at 3218 miles.
It now has 32,000.
So I can't see dirt or wear as an issue. I certainly appreciate that a sensor could be bad.
But. If that were the issue, why would BMW say crack the throttle? To avoid a service visit, and to avoid a sale of a new sensor?
That's my question.
dc

 

[roger 04 rt]

Roger
Two questions, first, does the BMSK run the 1150 the same as the 1200?
And secondly, if there is anything wrong with the BMSK operation, why does BMW still say crank the throttle?
Is there a fix? Or is it something not broke.
There is no fast idle lever on the 1200.
I use an oem battery. And where I had the issue was with a new battery (6 months old) after 3 solid all day rides.
I shouldn't say issue, because when I crank the throttle, like the book says, I have no problem.
However, there is no fast idle or run rich like on new cars. At least not sufficient to start on a cold day.
dc

David,
R1100 uses Motronic MA 2.2, R1150 Motronic MA 2.4, R1200 uses BMSK. But yes, they all fuel at cold start in the same way. I'm looking at a BMSK log as I write this.

I like the crack the throttle explanation below. How much and how long do you have to hold the throttle open?

There is a run rich program on your BMSK. That's why it extends the injection pulse so much.
RB

The manual says open the throttle a little when its really cold.

This is why.

Oil is thick, engine needs more gas AND air to fire up.

...

Perfectly sensible answer: it takes more power to rotate the engine through thick oil.

 

[DROOT153718]

David13.

It was a 175 cubic inch John Deere B about 24 Hp.
We also had a 350" A that would not start for chit warm or cold decompressors and all.

On our bikes the computer richens up the mixture by oil temp and intake air temp (IAT). It knows the bike is cold so it adds fuel for proper running. This is in the base fuel map because there are no inputs from the o2 sensor. This adds fuel for idle and beyond so you can drive away right after starting like BMW says to.

The IAC ( Idle Air Controller or steppers) should open up more. I don't know if they can't or do not.

So the fuel is there, just more of the mixed fuel and air is needed to carry on by opening the throttle a little.

When cold the heated o2 sensors warm up in a minute or so giving the computer needed information to keep emissions down and performance up. On older units (bikes or cars) A fast cold Idle was needed to lite the converter and warm up the o2 sensor. Cars in the 70s wanted 2600 RPM for initial RPM when cold. This helped emmissions, but was hell on the motor.

Look at the old carburetor engines. The choke would add fuel AND more air in some way. Really old cars had a fast Idle cam that just held the butterfly more open. Our bikes had an idle enrichening circuit which added more fuel AND air (like my airhead) to give that faster initial idle on start up until the choke was turned off.

Looking at a fuel injected car on the scanner, it has a spec "Desired Idle" which it tries to keep with the IAC. When cold its more than when warm. It seems my camhead always wants to keep the same RPM hot or cold. I detect no cold fast idle.

I am sure the computer gives more fuel when cold. If it did not, the bike would die when the throttle was twisted if it started at all. Fuel Injection is awesome. It does it all.
Our bikes are still behind the autos. A Mass Air Flow (MAF) sensor can detect how thick the air is. This helps adjust for cold temps, changes in elevation and even changes in air density.

I see no problem with twisting the throttle for a really cold start. I do not like starting the bike at more than idle RPM because the oil is not there yet.

When does the most engine wear? Cold start when there is no oil.

Just my two cents.
David

 

[roger 04 rt]

Roger
This is somewhat addressed to your post.
This, from the wizard of Santa Cruz.

"Example: That waveform upload looks impressive, but Lambda is not a cold factor AT ALL because oxygen sensor will not function until warmed up--one minute to five minutes depending on application--and controls will be in Open Loop with enriched, cold-start default until it functions. Always, no exceptions, every feedbqck vehicle on earth.

The best input is reset adaptations with GS911. However, this should be combined with throttle body cleaning, plus TPS and TB synch too, then reset all fuel and idle control adaptations. Absent any other symptoms, codes or corrupted sensor data, this is the first thing a competent dealer tech would do too.

Poor cold idle is almost always due to IAC not being properly commanded. If adaptation does not cure this, it is possible IAC is struggling to open up proper in cold temps, a common condition on high-mileage units, not so common otherwise."

My bike has performed like this since new, or since my purchase at 3218 miles.
It now has 32,000.
So I can't see dirt or wear as an issue. I certainly appreciate that a sensor could be bad.
But. If that were the issue, why would BMW say crack the throttle? To avoid a service visit, and to avoid a sale of a new sensor?
That's my question.
dc

David, Whoever you're quoting seems to know his/her stuff and is: 1) correct on all points and 2) in agreement with the chart I posted earlier. The only thing I don't understand is the "but" part since I hadn't mentioned the lambda sensor. In any case, on the BMSK, cold start does not make use of the lambda sensor until it is warm, usually 30-60 seconds on your bike (but 1-5 minutes on the 1150).

Still, your question is, "Is anything wrong with my bike?" So, I go back to my earlier question to you, how much do you crack the throttle open and once it fires, how long much you hold it cracked open?
RB

 

[David13]

Crack is about maybe 50 or 100 rpms. Maybe a roll of 1/8 or 3/16 of an inch, not much. As to duration to hold it, probably 10 or 20 seconds at most.
Then, if it's still idling too low, maybe a little roll but not for more than one minute, and only intermittently.
You know, raise the idle a 50 rpms for another 10 seconds.
So I can roll away in 1 to 3 minutes. Maybe let it warm up for that extra minute, or two.
dc

 

[David13]

Crack is about maybe 50 or 100 rpms. Maybe a roll of 1/8 or 3/16 of an inch, not much. As to duration to hold it, probably 10 or 20 seconds at most.
Then, if it's still idling too low, maybe a little roll but not for more than one minute, and only intermittently.
You know, raise the idle a 50 rpms for another 10 seconds.
So I can roll away in 1 to 3 minutes. Maybe let it warm up for that extra minute, or two.
dc

Oh, as to that quote, that friend is a top notch auto tech in Santa Cruz. Also an R1200RT rider.

 

[DROOT153718]

This is interesting. A couple questions. How fast can the steppers make the engine run.

after reading David13 situation. (not a problem to me) It seems the bike cannot attain the desired RPM when cold.

This IS wrong. If the throttle plates are too closed so the stepper motors are too far open for regular warm idle, maybe they cannot open enough for cold idle.

I am thinking crack the throttle to start the bike, not warm it up. NOW you have me going outside today to fire up my camhead and see what it does in 20*f.

Does the GS911 give the data of IAC position? Usually its 1 - 255. 1 being closed.


MY thought is if the throttle plate is closed all the way, the stepper (IAC) is already near 255 to attain desired idle warm.

If the plates were open more (ad of course matched) would the bike start better cold?

One more question, does the stepper close or open on decel when there is no fuel being delivered to the cylinder above 2,000 RPM?

Going to put the charger on my bike. It needs to be fired up and fondled anyhow.

David

 

[roger 04 rt]

...

Does the GS911 give the data of IAC position? Usually its 1 - 255. 1 being closed.


...

Yes it does provide that info. I have a lot of data from a friends 2010 R1200GSA that I can compare to. Based in the data I have, I will double check, but he doesn't seem to crack the throttle when starting.

BTW, my R1150RT starts in the detent for fast idle lever, which only open the throttle 1.9 degrees. Which pretty small amount.

 

[lkraus]

BTW, my R1150RT starts in the detent for fast idle lever, which only open the throttle 1.9 degrees. Which pretty small amount.

This is about the amount of throttle twist the 1200 needs for a cold start. So BMW achieved the same result by adding a line to the owners manual and deleting the fast idle lever. Saves complexity and weight, saves BMW money, and generates battery sales to folks that don't RTFM.

Presumably will not be an issue on the wetheads with throttle-by-wire.

 

[DROOT153718]

Yes it does provide that info. I have a lot of data from a friends 2010 R1200GSA that I can compare to. Based in the data I have, I will double check, but he doesn't seem to crack the throttle when starting.

BTW, my R1150RT starts in the detent for fast idle lever, which only open the throttle 1.9 degrees. Which pretty small amount.

The 1150 has no stepper motors. Same as my 1100.

We would need the information from the offending bike. All required would be what it is at hot and idling.

Roger, you could also put the GS911 on a cold 1200 and see what the stepper motors are at cold, and warm to see how much they open up for cold running and start.

David

 

[roger 04 rt]

The 1150 has no stepper motors. Same as my 1100.

We would need the information from the offending bike. All required would be what it is at hot and idling.

Roger, you could also put the GS911 on a cold 1200 and see what the stepper motors are at cold, and warm to see how much they open up for cold running and start.

David

Below is what I got from my friend with the 2010 R1200GSA.

Also, I looked through his log file from a 40F morning. The idle actuator positions were: 204 during cranking, 165 the moment the engine caught, 155 within 10 seconds and finally 125 when the engine was hot.

Another R1200, on a 50F day had settings of: 197 during cranking tapering to 90 when hot.
RB

I do NOT touch the throttle unless I feel like blipping it, which is rare.
It starts well, idles well, runs off well. I rarely let it warm up, I gear
up, start, a couple seconds later go. ... I do understand throttle opening when necessary.

Tomorrow morning it will be in the low 30's, I could get ya something if ya
want. I have started at 17F with no issue, I don't think his bike should be doing what it is.

T​

 

[deilenberger]

This is interesting. A couple questions. How fast can the steppers make the engine run.

after reading David13 situation. (not a problem to me) It seems the bike cannot attain the desired RPM when cold.

This IS wrong. If the throttle plates are too closed so the stepper motors are too far open for regular warm idle, maybe they cannot open enough for cold idle.

The throttle plates on the hexhead (and I'd assume camhead) are different from the R11xx throttle plates. The bore in the hex/cam TB is stepped so when the plates are closed, effectively no air goes around them. All idle speed control comes from the stepper motor bypasses. If you remove one of the intake hoses and open the throttle plate - you can easily see the stepped design.

I am thinking crack the throttle to start the bike, not warm it up. NOW you have me going outside today to fire up my camhead and see what it does in 20*f.

Does the GS911 give the data of IAC position? Usually its 1 - 255. 1 being closed.

MY thought is if the throttle plate is closed all the way, the stepper (IAC) is already near 255 to attain desired idle warm.

If the plates were open more (ad of course matched) would the bike start better cold?

This would probably cause problems. The only way to change the closed position of the throttle plates is with the screw that is never supposed to be touched (the one with green paint on the head that sticks up out of the plastic cover over the throttle sector pulley. This screw is adjusted at the factory so the plate JUST closes the bore completely, without the throttle plate resting with full spring pressure against the step in the bore. I would hazard a guess this is to prevent wear.

One more question, does the stepper close or open on decel when there is no fuel being delivered to the cylinder above 2,000 RPM?

Going to put the charger on my bike. It needs to be fired up and fondled anyhow.

David

One thought. The steppers on the hexheads have grease on the threads that move the plunger in and out. I wrote up on how to clean and regrease these threads on the R1200R website some time ago. It's possible as the grease ages that it becomes thicker, and that slows the opening of the bypass plunger when the temperature is cold (which will also tend to thicken the grease.) My bike had an occasional stalling problem which was fixed some by cleaning and regreasing these threads. It starts and runs fine by just pressing the starter button - down to 30F (which is as cold as I like to ride.)

A few photos:

I cleaned the threads using a Q-tip and some spray carb cleaner, then regreased them with a light white-lithium spray grease (which is what the grease on them originally appeared to be.)

Two warnings:

- Do NOT activate the steppers when they are out of the throttle-body. The "set-zero" function of the BMSK will extend the piston until it falls off the threads. I have been told it is difficult to get back together once that happens.

- Check the condition of the O ring used to seal the stepper to the TB - if in doubt - replace it. Make sure it is in place when you reassemble.

 

[David13]

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