'03 K12RS TPS reset - again

[RBEmerson]

Sorry - '03 K1200RS
The key on, twist, twist, twist drill is no longer working for me. I do key on with my left hand and start twisting almost instantly after the idiots light up. I go to WOT (hit the stop) three times, fire up the motor and... just as miserable at the low end as before. Am I missing something on this voodoo or...?

 

[pauls1150]

Not sure about your particular model, but my belief is that you MUST wait for the computer to completely boot up and run its self-check before doing the reset.
Twist slowly and control the return too.
Note that this resets the "initial values" of the fueling map; "actual riding condition" values are automatically trimmed in as you ride, and this takes a ride or two. Since we don't spend a lot of time at low rpm, that part of the map may take more time to self-remap. (It sure does when I pull the battery from my car...)
Or you may actually have a bad TPS? Not common but it happens.
Does it run well at mid and high rpm?

 

[RBEmerson]

OK, it's possible (likely?) I'm jumping on the reset routine too soon. How much time do I have before it's too late to reset the TPS? The rotation should slow, not fast? If so, that's something else I got wrong.

Aside from the TPS issue, everything else works as it should. The local Interstate raised the speed limit recently, making runs to 80-90 (by GPS - speedo is slightly fast) reasonably safe from LEO. Everything works fine.

I'll try the wait and slow drill a few times and see what happens.

 

[pauls1150]

It's never "too late". Just wait until ALL the lights stop blinking and the ABS has gone thru its routine; this whole thing is maybe 5 seconds or so.

The rotation doesn't have to "crawl", you just want to be sure the computer has the time to "see" the entire voltage sweep with no "holes" in the data. Older TPSs used a wirewound element (dual potentiometer), and the newer ones are a solid carbon amalgam, but either one could get wear or dirt on where the wiper contacts it; also note that if it has an internal crack, that would certainly screw up the attempt to reset it.

 

[mehrten]

RB,

Find a friend with a GS-911 diagnostic tool.

It will help you set the TPS and/or find out if you have either a bad TPS or a bad throttle actuator.

The bike is 13 or 14 years old, things wear out.

I went through several set/resets with a GS-911 on our 2002 K1200RS.

It's not that difficult...once you get the hang of it.

RealOEM.com is a good site to help figure out how things go together: www.realoem.com/bmw/select.do?kind=M&arch=0

Good luck on getting it sorted out.

Deryle Mehrten
Sierra Vista, AZ USA

 

[RBEmerson]

OK, I have a better sense of timing the routine. I'll report back on how it works out.

TPS' in general aren't my friend. I spent far too much time sorting out the TPS on our '90 VW camper. I replaced the throttle body (a story in itself - the installation was easy, the reason why... oh nevermind) and the TPS that came with it was supposed to be good to go. Good to go into the trash, perhaps. I wound up buying a $75 TPS that, at least, could be set up without consulting a voodoo priestess. The thing is simply a micro-switch that's twisted to spec and locked down. This TPS looks more like the pot on the air mass sensor's "barn door" flap. Which needed a good cleaning. Sigh...

If the twist 'em routine doesn't work, I may just invest in a GS-911 rather than take it to the dealer just read "The Codes".

 

[RBEmerson]

I'm now advised to wait until the idiot lights stop their start-up light show, and then roll the throttle with ...um... due deliberation, not crank thing like a man obsessed. The result are somewhat better. Only. What I seem to be up against is how long the computer will accept calibration activity.

 

[pauls1150]

The computer is ALWAYS "trimming" the map; the only way to "speed up" the low-rpm trim is to spend more time at the bottom of the rev range, which a K motor does not like anyway.

The K12 had several recalls, possibly including the airbox which had a direct effect on idle & low rpm running (I may have the year/model confused) ... have you verified that all recalls have been performed? Some years/models have had issues with vacuum lines that need to be R&R'd.

And there may be a different solution entirely to this problem which has not yet been hit upon...

 

[8ninety8]

Does any of this map reading apply to the early jetronic computers? Like an '85 K? Or are those control units/computers set, period?

 

[98lee]

Does any of this map reading apply to the early jetronic computers? Like an '85 K? Or are those control units/computers set, period?

No, does not apply. These very early FI systems had very few sensors and virtualy no adjustability. But they were light years better than carburetors.

 

[RBEmerson]

The computer is ALWAYS "trimming" the map; the only way to "speed up" the low-rpm trim is to spend more time at the bottom of the rev range, which a K motor does not like anyway.

The K12 had several recalls, possibly including the airbox which had a direct effect on idle & low rpm running (I may have the year/model confused) ... have you verified that all recalls have been performed? Some years/models have had issues with vacuum lines that need to be R&R'd.

And there may be a different solution entirely to this problem which has not yet been hit upon...

I still don't understand whether or not there's a "window" for doing the throttle grip routine. I think you're saying I could actually start the motor, stop it with the kill switch, rotate the throttle, re-light the motor without using the key, and still get the TPS recalibration?

I have nothing from the PO about the bike's service history.

 

[pauls1150]

No window.
Key on and kill switch in the Run position.
Don't start it, just let it boot up.
Twist slowly a few times.
Key off.
Done.

Present your VIN to your local BMW service manager - if recalls or "campaigns" were done, it's recorded in ze master komputer. They will also have history of any other dealer services.

 

[RBEmerson]

No window.
Key on and kill switch in the Run position.
Don't start it, just let it boot up.
Twist slowly a few times.
Key off.
Done.

Key off is required? (Just trying to make sure I get the voodoo right)

Present your VIN to your local BMW service manager - if recalls or "campaigns" were done, it's recorded in ze master komputer. They will also have history of any other dealer services.

Hmmmm... good point.

 

[Bobmws]

Key off is required? (Just trying to make sure I get the voodoo right)


Hmmmm... good point.

Yes,key off. I think I said that in the other thread, but I'm old and may have forgotten....

Also, have the dealer check service records, there was a cold start update for '03 & early '04. Not sure if that's applicable to your issue, but should be checked.

 

[RBEmerson]

Y'know, it helps to get magic spells right or Bad Things Happen.

I don't have starting issues but I'll follow up anyway. I hope all I find is good news.

 

[pauls1150]

Umm, just to be clear, as there seems to be a little confusion:

Before you begin the process, the key is often off.
It has to be on to do the reset. This is "active electrical".

Then the steps per my earlier post.

You don't "have" to turn the key off afterward; the computer has the new information and you may then just start it up and ride it.

Who do
the voodoo?
You do
Woo-hoo!
And don't forget to sacrifice a virgin black cat first.

 

[RBEmerson]

OK, from the top:

1. Key off
2. Key on
3. Wait for lights to stabilize
4. Roll, at a moderate rate, throttle from fully closed to WOT and back
5. Roll, at a moderate rate, throttle from fully closed to WOT and back
6. Roll, at a moderate rate, throttle from fully closed to WOT and back
7. Key off

On completion, test ride bike. A lot.

Working in the dark of a new moon, task completed at midnight, and Dr. John the Night Tripper music optional

 

[gregfeeler]

Sorry - '03 K1200RS
The key on, twist, twist, twist drill is no longer working for me. I do key on with my left hand and start twisting almost instantly after the idiots light up. I go to WOT (hit the stop) three times, fire up the motor and... just as miserable at the low end as before. Am I missing something on this voodoo or...?

When you say it's miserable at the low end - could you describe this? Did it run better at some point? Just curious. Thanks.

 

[RBEmerson]

Presently, right near the bottom of throttle travel, the motor goes from running at whatever revs should be happening directly to idle with no gradation in between. Effectively, it's go/no go. Unfortunately it's noticeable in any gear. If I'm going down the road in 5th or 6th and have to back off for some reason, it's the same go/no go. The motor doesn't quit, stall, or go sour, it suddenly drops to idle instead of gradually going slower the more I back off the throttle. Again, this at the bottom of the throttle range or where I'd expect to find TPS problems. Otherwise, the motor idles at about 1K, starts readily, pulls like a freight train, and will hit 100+ with no complaint. In short, the motor's running great.

The more I think about it, the more I'm not sure when (or if) the problem didn't exist, at least to some degree. I've had the bike for a few years, so some of the details from early on are lost.

My plan, at this point, is to let the dealer have a shot at it. I'm sorely tempted to have the TPS replaced, period. I've had fights with TPS' on cars, and it's never been fun or easy to get them right (in the end I win, but I'm not fit for human company afterwards). Which tilts me towards saying "just replace it whether it needs it or not" - all of that as part of the task to "make the problem go away".

HTH

 

[gregfeeler]

Presently, right near the bottom of throttle travel, the motor goes from running at whatever revs should be happening directly to idle with no gradation in between. Effectively, it's go/no go. Unfortunately it's noticeable in any gear. If I'm going down the road in 5th or 6th and have to back off for some reason, it's the same go/no go. The motor doesn't quit, stall, or go sour, it suddenly drops to idle instead of gradually going slower the more I back off the throttle. Again, this at the bottom of the throttle range or where I'd expect to find TPS problems. Otherwise, the motor idles at about 1K, starts readily, pulls like a freight train, and will hit 100+ with no complaint. In short, the motor's running great.

The more I think about it, the more I'm not sure when (or if) the problem didn't exist, at least to some degree. I've had the bike for a few years, so some of the details from early on are lost.

My plan, at this point, is to let the dealer have a shot at it. I'm sorely tempted to have the TPS replaced, period. I've had fights with TPS' on cars, and it's never been fun or easy to get them right (in the end I win, but I'm not fit for human company afterwards). Which tilts me towards saying "just replace it whether it needs it or not" - all of that as part of the task to "make the problem go away".

HTH

Maybe I've just been lucky, but I've never had a TPS problem on any vehicle, and that includes many that had them - including a lot of BMW bikes and German cars. So knocking on wood right now.

From your description I would agree that your TPS is the most likely suspect. There's nothing else in that FI system that I know of that directly controls fuel flow as a function of throttle position. You have a mechanical throttle, so although the butterfly's will be in the wrong position for idling if the TPS is sending wrong info the the fuel computer you could get just an idling amount of fuel through the injectors. I'll be curious to know what you find if you post the results here.