Rough idle & stalling when hot

Hello,
Newbie here so be gentle!
I got an 08 gs at the start of June and have been lurking here ever since. The bike has low miles, just under 15k when I got it, and a full dealer history up until about 2 years ago. In the last 2 years it’s done virtually nothing. It got an oil change and final drive change done by supplying dealer.
I had some disappointing issues in the first weeks of ownership; slipping clutch, front main oil seal leak, fuel strip u/s, RDC sensors dead. I’ve zapped the strip which seems to be working, swopped the RDC sensors for some AliExpress specials, and coded them in with newly acquired Motoscan app, and had new clutch and oil seal fitted at supplying dealer’s considerable expense.
I was finally starting to enjoy the bike a bit when it started cutting out at low revs the other day, typically at slow speed or when idling. I hooked up the Motoscan today and got a stored fault code 2722 for oxygen sensor 2.
I’m now scouring t’internet for a reasonably priced lambda sensor but before I place the order has anyone got any other suggestions of what to check? Bike runs fine once off idle and no issues when cold. Got a new battery on order as the existing one doesn’t fill me with confidence although the multimeter says it’s ok.
If I go ahead and swop out the o2 sensor is there anything I need to do ecu wise to get it to work?

Cheers

John.

Plug and play It just sends data to the ECU

What happens if you clear the code? Does it come back ?

It’s weird. Went for a wee ride yesterday to fill up with premium fuel, just in case it was duff petrol thought it was worth a punt. Fault code wasn’t stored when I got home. I then hooked up Motoscan, started bike and ran it for a short time and fault was stored. Looking back now it might have been “captured” whilst the bike was running. Can’t remember if I checked before or after I turned motor off. I haven’t tried again, just took a photo of stored message on Motoscan and cleared it. I then removed the sensor. I was expecting a battle given the age of the bike but it came off no bother. The coil cover and surrounding area was a bit oily. Not sure if it had migrated from original front seal leak via airflow as no other obvious source. I think I’ll try cleaning the sensor and refitting this morning.

Pics attached of error messages. Don’t know why they’re sideways

make sure there isn't a box of tricks meaning they were deliberately disconnected - a PC3 or PC5 would get that error in diagnostics (it will clear but of course pop back as soon as you start it)

as far as the bike goes it doesn't really care if they are connected or not - its more for the longevity of the CAT

My bike went mad (straight after it was at a dealership - funny that) eventually I swapped the TPS and it improved back to the standard gibbering wreck they were when leaving the factory

Gave the sensor a soak in brake cleaner this morning but it hasn’t made any difference. Same as before. Bike starts and runs ok from cold but then stalls or barely idles once warmed up. Fault code is logged on Motoscan again.

botus said:

make sure there isn't a box of tricks meaning they were deliberately disconnected - a PC3 or PC5 would get that error in diagnostics (it will clear but of course pop back as soon as you start it)

Click to expand...

No aftermarket tuning modules fitted. I have considered obtaining a box of some sort. Much time has been spent wading through posts about booster plugs, AX-FIED units and Treetop�� remaps.

When the bike is cold it is in open loop ( lambda sensors not used) until it warms up then goes into closed loop, ( using the lambda sensors).
If the lambda sensors are disconnected the ecu will revert to a lambda of 1.0 .

Replacement o2 sensor ordered. I’ll let you know how I get on.

Watching with interest as have similar issue, keep us posted..

if you unplug CAT sensors it will run just the same but stuck on a non evolving base map (and it doesn't show an error to the rider)

e10 wasn't meant to go in an old GS, try BP 97 closest product out there to what it was meant to run on

esso 99 in parts of the country is ethanol free (which u want in any road vehicle) and it might feels smoother but you should be losing a little bit of go - the spark kicks off based on 95 octane needs

Throttle Position Sensor - the black bit you kick with your left shin - as you'll never get sensible readings off the TPS without a spare plug with tails on the multiplug connector - I doubt you'll be able to correctly identify if the TPS is mostly dead - but they fail and they are so easy to swap, a spare in your pocket could be a good idea to try on the bike and see if it behaves a lot less badly

that paragraph above I'd never have believed till I just swapped my 30k mile TPS and the bike was far happier. The numbers below were after i had it off the bike having swapped it out - and I have the connector with tails and cables with crocodile clips to make testing feasible - however I didn't believe anything could be wrong - as I have a PC3 and in its software you can see the bikes 0% to 100% throttle position move without any glitches or missed readings from the bikes own TPS and set the upper an lower values for closed and fully open throttle so the PC3 and the Bike are starting with the right info.



following the info in this PDF https://www.r1200gs.info/threads/re...althy-tps-unit.49975/#lg=thread-49975&slide=0 the original TPS seemed close enough I wouldn't expect a change, and I couldn't see anything amiss in the PC3 values on screen, but when I rode it, it was clearly far less unhappy with a new TPS

However to add confusion reading part numbers for my bike June 2007 GS - the listing shows two - with a 4 k ohm sensor (same part on the GS1200 or K1300GT) and i don't know if both are compatible or one is in conjunction with something else ???


RealOEM.com - Part Search

02 Throttle valve switch 1 13547696412 $175.46 I think its saying 4 KOHM no longer available after 12/2015
02 Throttle valve switch 1 13548406249

info on testing as per pdf link - gadget set at 200k ohms (umm updated the figures but still confused. its more wrong than I recollect) my numbers on the right were for part 13547696412

fully clockwise
Pins - Std - mine
1 & 2 - 5.30 - 4.70
1 & 3 - 4.40 - 3.80
2 & 3 - 0.70 - 0.80

fully anti-clock
Pins
1 & 2 - 0.90 - 0.90
1 & 3 - 0.90 - 3.80
2 & 3 - 1.50 - 4.70 (this is a bigger diff than I remember)

After I swapped, it was definitely running much better at low speeds and light throttle - still nasty and glitchy but that's how they run. For example my stock K1300 wasn't perfect on its original map but it was light years on for a std GS cough and jerk emission disaster they sold them with.

FWIW.

One way to verify if there is an issue beyond a faulty O2 sensor is to disconnect the o2 sensors and clear the adaption values.

This will revert the mapping to an un-corrected basemap wich is what you get when the bike is brand new. It is usually set up in such a way that the bike may run slightly on the rich side, but still run very well. (After all, BMW does not want to sell a bike that runs horrible when the customers leaves the dealer on his brand new bike).

The bike will of course throw an internal faultcode for the missing O2 sensor, but if it is an O2 sensor issue only, the bike will run quite well, and if there is an throttle position sensor issue, the issue will be there....

knutk said:

FWIW.

One way to verify if there is an issue beyond a faulty O2 sensor is to disconnect the o2 sensors and clear the adaption values.

Click to expand...

So, run the bike with the sensors disconnected. How do I clear the adaption values? Suppose I could also swop the sensors from side to side to see if the fault switches sides.

botus said:

e10 wasn't meant to go in an old GS,

Click to expand...

My understanding was that e10 is ok to use, with the caveat that it’s not good to leave in tank if bike is off the road for any sustained period. Have I got that wrong?

Thanks for all the info about the TPS. I think I’ll try and eliminate/ confirm that it’s the o2 sensor that’s at fault first but it’s all good to know.

jonbenj979 said:

My understanding was that e10 is ok to use, with the caveat that it’s not good to leave in tank if bike is off the road for any sustained period. Have I got that wrong?

Thanks for all the info about the TPS. I think I’ll try and eliminate/ confirm that it’s the o2 sensor that’s at fault first but it’s all good to know.

Click to expand...

To clear the adaptations either use a GS911 or Disconnect the battery for a few minutes.
If you run with the lambda sensors disconnected the ecu will revert to the default, a lambda of 1.0 (Stoichiometric) for petrol this is an Air Fuel Ratio of 14.7 to 1, For E5 this is approx. 14.3 to 1 and for E10 it is approx. 14.1 to 1.
So if you are running lambda sensors it will compensate for the different fuels , if you disconnect them it will not be able to adapt the base maps but will run ok`ish If you run AF-XIED`s no problems everything is dealt with go setting 7 and smile.
With a PC 3 and the lambda sensors disconnected even with accurate AFR recording equipment I found myself having to alter the fuel tables every morning whilst touring as the fuels were not consistent.

botus said:

if you unplug CAT sensors it will run just the same but stuck on a non evolving base map (and it doesn't show an error to the rider)

e10 wasn't meant to go in an old GS, try BP 97 closest product out there to what it was meant to run on

esso 99 in parts of the country is ethanol free (which u want in any road vehicle) and it might feels smoother but you should be losing a little bit of go - the spark kicks off based on 95 octane needs

Throttle Position Sensor - the black bit you kick with your left shin - as you'll never get sensible readings off the TPS without a spare plug with tails on the multiplug connector - I doubt you'll be able to correctly identify if the TPS is mostly dead - but they fail and they are so easy to swap, a spare in your pocket could be a good idea to try on the bike and see if it behaves a lot less badly

that paragraph above I'd never have believed till I just swapped my 30k mile TPS and the bike was far happier. The numbers below were after i had it off the bike having swapped it out - and I have the connector with tails and cables with crocodile clips to make testing feasible - however I didn't believe anything could be wrong - as I have a PC3 and in its software you can see the bikes 0% to 100% throttle position move without any glitches or missed readings from the bikes own TPS and set the upper an lower values for closed and fully open throttle so the PC3 and the Bike are starting with the right info.

following the info in this PDF https://www.r1200gs.info/threads/re...althy-tps-unit.49975/#lg=thread-49975&slide=0 the original TPS seemed close enough I wouldn't expect a change, and I couldn't see anything amiss in the PC3 values on screen, but when I rode it, it was clearly far less unhappy with a new TPS

However to add confusion reading part numbers for my bike June 2007 GS - the listing shows two - with a 4 k ohm sensor (same part on the GS1200 or K1300GT) and i don't know if both are compatible or one is in conjunction with something else ???


RealOEM.com - Part Search

02 Throttle valve switch 1 13547696412 $175.46 I think its saying 4 KOHM no longer available after 12/2015
02 Throttle valve switch 1 13548406249

info on testing as per pdf link - gadget set at 200k ohms (umm updated the figures but still confused. its more wrong than I recollect) my numbers on the right were for part 13547696412

fully clockwise
Pins - Std - mine
1 & 2 - 5.30 - 4.70
1 & 3 - 4.40 - 3.80
2 & 3 - 0.70 - 0.80

fully anti-clock
Pins
1 & 2 - 0.90 - 0.90
1 & 3 - 0.90 - 3.80
2 & 3 - 1.50 - 4.70 (this is a bigger diff than I remember)

After I swapped, it was definitely running much better at low speeds and light throttle - still nasty and glitchy but that's how they run. For example my stock K1300 wasn't perfect on its original map but it was light years on for a std GS cough and jerk emission disaster they sold them with.

Click to expand...

As you say the TPS should be regarded as a service item. The wiper is doing a lot of traveling on the carbon track in 30K miles.
I use the Hella units from ebay as fitted to many BMW cars which are identical . They are 4.3K ohms , even have one fitted to the Bing carburettors on my Airhead ( for diagnostic purposes).

jonbenj979 said:

My understanding was that e10 is ok to use, with the caveat that it’s not good to leave in tank if bike is off the road for any sustained period. Have I got that wrong?

Thanks for all the info about the TPS. I think I’ll try and eliminate/ confirm that it’s the o2 sensor that’s at fault first but it’s all good to know.

Click to expand...

depends what you mean by OK, will it start, yes, will it run as well and make as much power no, was the first GS1200 designed to run it no, - does the manual mention E10 no, it didn't exist back then

by 2010 they had seen E5 coming and they altered the later bikes to cope, was E10 supported, not on a 2011 K1300 - I guess E10 support started around 2013 on the GS LC bikes ?

I bow to Misticat's superior knowledge on lamba mumbo jumbo and what ethanol is doing to AFR - but he makes a great point explaining why my bike with a PC3 on it always ran like an utter dog if you used french E10 filth

I disconnected both my o2 sensors a month ago. Bike running much better without them. It wasn’t stalling before but it did have rough running due yo an o2 sensor failure. I’m not going to spend over €500 replacing the two of them.