Rough Running R1200GS 2007

[Chris.S]

I would say 12 years experience counts for an awful lot and for me everyday is a school day I am only trying to help and learn at the same time.
  I am missing something the idle actuators are the same readings although I realise that there is no feed back loop to the ecu to tell the ecu their position.
  But according to the data and the op the idle is fine, the problem is at 2000 rpm when one lambda sensor is reporting a rich mixture of 11 to 1 and consequently the ecu is leaning out the mixture.
  Hence the injector pulse width is less at 2000 rpm with 2% throttle than at idle with 0% throttle.
  As I said earlier I thought the idle actuator position looked a little low at 75 steps at idle I would normally expect to see around 116 steps.
 

[mike d]

Hi Jughead, Chris,

Thanks for your contributions thus far.

He swapped the idle actuators over, and also removed them to test as you suggested, they were operating as per the video clip.

I fully agree with your statement :

Replacing a lambda sensor because it is giving a rich reading is like running a fever and then tossing out your thermometer because it is giving you a high temp reading.

And that's also not what the owner was suggesting. He was looking to understand what was not common to both sides, the injectors have been swapped.

He has a long riding holiday planned in early August, so was trying to get it sorted before then. He had an appointment with the local BMW main dealer today, but I've not heard back from him yet on what if anything has been found.

I will report back on on the findings.

Regards

Mike
 


 

[Chris.S]

Hope he gets it sorted, it will be very interesting to see what the problem was. 

[mike d]

Latest episode

There was good news and bad news from the visit to North Oxford today. The bad news is that they haven't been able to track down the problem, or cure it. The good news, part 1, is that I persuaded them to pull the TPS from a used RnineT and try that. It didn't work, but at least that's one component ruled out. The other good news was that they only charged me for an hour's labour, when I suspect they spent more like two hours on it.

Initially, they claimed they had seen suspect data from the TPS: just off a closed throttle, they reckoned it jumped to 100%. That's something I've never seen with the GS-911, and it doesn't fit with the behaviour; if the ECU thought the throttle was wide open, it would instruct the injectors to dump lots of fuel in, which would then make it run catastrophically rich since the butterflies would still be shut. Also, since there's only one TPS, any issue with that would affect both cylinders equally.

So I'm a little further forward. What I have found is that I can get two used lambda sensors, plus two throttle bodies – complete with idle adjusters, injectors and a TPS – from James Sherlock for less than £90. So they should be with me by the weekend. If the problem is still there after changing that lot, I will be completely stumped as to where to go next!

Mike

[Chris.S]

I too would find their TPS finding dubious, normally the track gets dirty although I have seen a wiper come adrift giving an 85%  reading at closed throttle showing an injector pulse width of over 10ms when trying to start the bike, it was swamped with fuel but of course it was on both cylinders.

 Good luck with the replacement parts it will be interesting to see the results.

[mike d]

Not only do I find the TPS suggestion strange, but apparently they didn't mention finding any issue with lambda sensor readings.

Latest update from Martin:

If they saw the unusual lambda readings, they didn't mention it, and I forgot to ask. I doubt they swapped the coils, either, since swapping the TPS had clearly not occurred to them until I mentioned it.

The throttle bodies came today, which was ultra-speedy, though not the lambda sensor; because it's all on ebay, they're separate orders. I've now swapped the idle actuators (and remembered to run the adjustment routine), the injectors, and the TPS (remembering to do the re-learn routine) and none of it has made any difference; it still stumbles like a drunkard just off idle. Here's hoping the lambda sensors sort it out – I'm running out of bits to replace!

Mike

[Chris.S]

 Was there ever a resolve to this problem.
  If so an update would be good to store away in the brain cell for future use.

[mike d]

Hi Chris,

The story's not finished yet.

The last work he did was to make a manometer (I was going to send him one), and check the throttle body balance.

Well, the bike has me completely flummoxed. I spoke to an independent specialist BMW mechanic; he said that my description of it stumbling just off idle was consistent with the primary coils breaking down. So I ordered a pair of new coils, plus a pair of used secondary coils; they made no difference whatsoever.

I put together a DIY vacuum gauge using lengths of clear plastic tubing and automatic transmission fluid; the bodies were considerably out of balance. They are now balanced at 2,000 rpm and above, though there's still a difference at idle. That's made it run a little better, but hasn't resolved the problems of it refusing to idle when cold, and stumbling/running rough between idle and 2,000 rpm.

He went on holiday yesterday, so a full update will be posted on his return.

Regards

Mike

 

[Chris.S]

 I will keep an eye on this post.
 Regarding balancing, of the several sets of carb balancers  I have I prefer the Morgan Carbtune Pro, with the steel rods.
  I tend to balance the carbs at the point when the throttle butterfly`s are just starting to move, I feel that if they are right at this critical point then the difference at 2000 rpm and up wont make that much difference.
 It would be nice to have them perfectly balanced all he way through but with the cables and plastic junction box that is not going to happen.
   At the end of the day this does not account for the data reading on the one lambda sensor being wrong.
  It is a shame that the AFR can not be measured on each cylinder just to confirm the data.
  I guess I am spoilt having welded extra ports in the headers to take wide band sensors and using an Innovate LM2 to monitor AFR .   

[mike d]

Hi Chris,

I run the tool hire facility for the BMW Club (UK), and we also have a couple of Carbtune Pro's, which is what I offered to the member. Good piece of kit.

Mike

[Jughead]

If he is confident the idle actuators are working 100% as they should, he could check the plastic clip/cover behind the throttle bodies.  If they are not seated correctly, it could also create an imbalance in the bodies.  Both cables MUST have a small amount of freeplay when the throttle is fully closed.

[mike d]

Hi Jughead,

Thanks for the suggestion, I'll pass it on for when he gets back rom holiday.

We have been shielding since mid March, but are now allowed visitors etc, so it may be possible for him to ride over to my place as he is about 50 miles away.

Mike