R1200rt 2009 - throttle stuck on Max :-s

[HMMMYA]

R1200RT 2009 ex Police 56000
1yr owned – 1st 6 mth ran regular 1k/mth then last 6mth parked mostly but taken for a short spin every wk. Parked on street and used all weathers.
New to R bikes to comments would be much appreciated.
In the last mth I jumped on the bike and found the engine was not returning to idle properly on a short run. I switch off and worked the throttle back and forth to its limits with the hope it was a sticky cable. This made things significantly worse. I took it for a spin and found the bike would regularly stick open at full throttle :-s The bike is now stuck on full throttle although the cable at the twist grip appears to have the correct feel and the twist grip returns nicely.
Other area of note.
1 header pipe from 1 cylinder is significantly cooler after a short run.
GS 911 – states 1 lambda sensor and speed sensor is faulty. All output tests however seemed fine ie injectors etc.
I am hoping I can pull the fairing of this week and find a fault along the throttle cable route or in the throttle cable splitter box. Am I looking in the correct place? I thought I’d ask advise from people more familiar with these bikes. I will be doing it in the street so the less work I need to do the better.
Comments would be greatly appreciated in terms of potential cause and any odd tools I may need.
I’m not too daft on the tools but been riding a k100 for yrs and so out of the loop with more modern tech.
Cheer
Duncan

[HMMMYA]

ok. So far i have found what looks like a throttle position sensor on the LHS throttle body has corrosion problems underneath it where the pivot point comes out. The aluminium corrosion was thick and crusty underneath the sensor which locking the LHS throttle body open due to friction in the centre pivot. This bike is was ridden hard through a Scottish winter last year so it's been hammered with salt. I scraped out the corrosion and worked free then pumped area with grease before re assembling sensor on top. Works smoothly now open to close. Started once and idling at 5k. Turned off and then battery was flat so have to put on charge before I can finish. I'm hoping I just need to reset idle??? Maybe balance throttle bodies while I am at it. Not sure how to do this yet on an R . I have a carbtune, any advise would be appreciated. Cheers

[HMMMYA]

Ok removed the grease from the TPS location area after realising there was a risk of contaminating the TPS due to it being inside the seal. I popped open the TPS to make the internals.werent gubbed but all is clean and appears good. Charged battery on the bike I reinstalled TPS and started it up. A high idle.of 5k remains however throttle opens and closes as normal. I disconnect the TPS all together and start and the idle back to normal circa 1k, I blip throttle and it stalls. Does this suggest the TPS is goosed? Did have much of a chance to tinker and day light is now gone. Comments welcome. Thus far no.comments? Not sure if I'm not using the site properly or maybe it's not a very techie forum. Any recommendations for alternatives forums.welcome too. Cheers

[PeteM]

You are using it fine and there are very technical people around here but if no-one has had the same problem they are unable to contribute.


But having said that please continue with documenting you diagnosis as that may be helpful to others.


One thing I would say is that on the whole anything that should not be greased or oiled, once greased tends to be toast as something that sensitive is pretty much impossible to fully degrease, but having never had to fix a TPS so what do I know?

[David.]

I am hoping I can pull the fairing of this week and find a fault along the throttle cable route or in the throttle cable splitter box.

I'd start with the basic mechanical checks. Looking back, found a thread where the throttle cable had jumped off the pulley in the splitter box.

viewtopic.php?t=4

[David.]

I'm hoping I just need to reset idle? Maybe balance throttle bodies while I am at it. Not sure how to do this yet on an R.

Checking the throttle body vacuums/balance will help to determine what's going on when the throttle is closed at idle.

https://motorcycleinfo.co.uk/bmw-r1200g ... index12f4/

My understanding is that the stepper motors control the idle speed, I believe they need zeroing & resetting as part of the throttle body synchronisation.

On my own bike, I don't do this myself, "I get a man in".

[David.]

I scraped out the corrosion and worked free then pumped area with grease before re assembling sensor on top.

Looking at the Haynes manual, there is a section on sensors, inc. TPS.

The sensor monitors the position of the butterfly valve in the left-hand throttle body and the ECU uses the information to determine fuelling and ignition requirements.

Removal and installation

Note: The sensor should not be removed unless it is known to be faulty. When a new sensor is installed its position must be reset using the BMW diagnostic tester.

[David.]

GS 911 – states 1 lambda sensor and speed sensor is faulty.

A faulty lambda (oxygen sensor) may also send mixed messages to the ECU which controls the fuel/air mixture accordindly.

[David.]

Does this suggest the TPS is goosed?

Looking at this thread, https://www.ukgser.com/forums/showthrea ... ion-Sensor the TPS may be u/s.

"It goes straight to 5000 revs which is exactly what happened to a friend of mine when he broke the TPS in a drop".

A high idle of 5k remains however throttle opens and closes as normal.

[HMMMYA]

Thanks for comments.


David - thanks for the link I found it previously and split open the unit to be pleasantly surprised it was clean and uncontaminated so thought best to leave it alone. I am still suspicious of the TPS  but seeing the condition of it has made it drop down the list as a faulty parts. Where I previously noted grease, I only put this into the machined blind counter bore directly below the TPS where the circlip and Teflon washer sits and where frosted corrosion had built up. I have since removed all this due to realising the risk with the TPS.


Your Haynes manual note say it needs reset using a BMW diagnostics tester. This is flagging red with me. Can I do this with the GS-911? I have a Chinese one at the mo which I fuddled my way around but don't know it well enough or the RT systems yet to do much other check codes. I notice reset options but deliberately do not touch them due to my limited knowledge.


Regarding faulty lambda sensor, thanks for the comment I agree. My only hesitation is that I suspect it has been goosed for a while since idle has not been perfect for a bit but equally not drastically out ie 5k. I will purchase a new one but first I'm going to run over the connectors and clean terminals etc.


Re splitter box. This was all in good condition and 3 cables all move freely and connected. The LHS TB cable was definitely prevented from returning with the TB spring due corrosion On the pivot under the TBS. This is now resolved.


Re TB syncing keen to read this but on the fly at the mo and will comment later. It's been on my mind to do this for sometime due to less than perfect idle.


Appreciate your time replying. Cheers

[David.]

Your Haynes manual note say it needs reset using a BMW diagnostics tester. Can I do this with the GS-911?

Yes, I believe so, again, I don't have any diagnostic equipment myself, it's all a bit too technical for me.

[David.]

Regarding faulty lambda sensor, thanks for the comment I agree.

As you say, it's most unlikely that the lambda sensor is causing the problem you have.

I'd do the diagnosis by a process of elimination, one thing at a time. The symptoms you have do seem to point towards the TPS.

I disconnect the TPS all together and start and the idle back to normal circa 1k, I blip throttle and it stalls.

Disconnected, the TPS/ECU doesn't know the position of the throttle body butterfly. Presumably, more air will go into the engine without the associated fuel, hence the stall.

[David.]

Should a new TPS be required, found this posted by Pete (milleplod) elsewhere, https://www.bmbikes.org.uk/viewtopic.php?f=85&t=26836

Looks like it's the correct one for a Hexhead, £132 from Motorworks, https://www.motorworks.co.uk/vlive/Shop ... rch=SEARCH

BMW #13547696412


Hella Sensor Throttle Position 6px 008 476-111 for BMW

[HMMMYA]

lol , after reading the same article I've bought it already! Thanks for looking this out for me though. I was wondering about posting a separate thread on it for comment. Also I found some alternatives for the O2 sensors which I was going to float, I've hesitated to buy them tho since there may be logic in buy 2 if they aren't identical and as you suggested I thought I'd tick of one thing at a time.

[David.]

Also I found some alternatives for the O2 sensors which I was going to float.

Please post any details in this thread, viewtopic.php?t=44.msg50186#msg50186 might be useful for future reference, thank you.