Running rough and high fuel consumption

hatzyian

hatzyian

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Can anyone give some advice, ----- what a silly question on this forum:blagblah

2008 GS, about 3 weeks ago, started to run rough, with slight staggering around 3,000revs. Then idle became very lumpy, as if running on 1.5 cylinders, and staggering right up to 4,000revs.
I took it to our local BMW dealer who stuck it on the computer, nothing came up. Suspected blocked/dirty injectors and advised me to stick some injector cleaner in tank and see if that cured it. (Before they started cleaning/changing injectors)
After about 300km of this, just getting worse, plus the fuel consumption has gone through the roof, instead of 6lt/100km, its now on 8lt/100km, exhaust is very sooty.
When I start, idle is fine for about 30 seconds, then lumpyness (tech term) starts. Power at high revs seems OK. No nasty mechanical noises. It seemed to clear for a while and now is back big time.
I've cleaned every electrical conection I can see, and run bike with different plug leads disconected, plugs/coil packs seem OK.
Any suggestions?, sensible ones please.
 
I've had what sounds exactly the same, took it to Bath road in Bristol who had a quick look and mentioned that my throttle bodies were balanced on idle but up to 3000 revs and then close the throttle and the left body stayed open, they suggested cleaning the idle actuaters which i did, seems ok at the moment although idle actuaters didnt seem to be dirty anyway :nenau
 
You say you have tried the plugs etc.

Have you actually tried to run it on 1 coil pack? Disconnect the other 3 coils and it should start. Try this on all 4, one at a time.


Sounds like you may have already done this but it does sound like a failing coil pack.
 
Basics

I would start with the basics, check compressions, valve clearances, throttle body balance, don't assume that it must be something very technical. :beerjug:
 
Throttle Position Sensor

TPS gave those symptons, also failed to register as fault on dealer's machine.
 
Thanks for all the info, I'll try some stuff later today.

Dippy, you say clean the idle actuators, remove from intake bodies?

I'll try starting with only one coil pack conected. Can't remember if I did only 1 pack.

If I disconect the Lambda probes, will this show if they are the problem?

TPS, anything I can do to it?

Its the fact that it seems to come and go, and running very rich that makes me think its a probe/sensor.
 
OK, have just done some work.

Would not start with either LH plugs connected.

Would run with either LH plugs conected.

Would start and run with either RH plugs connected.

Would not run with RH injector disconected.

Would run with LH injector disconected.

Interchanged injectors---- all above the same.

Interchanged idle actuators------ all above the same.

Removed Lambda sensors, LH very sooty, RH dirty.

Cleaned sensors, and interchanged.

Still the same. Problem is LH side. Going to try to interchange coils now.
 
Just for info.

After alot of swapping things, the problem seemed to be one Lamda sensor. If I swapped it to different sides, that side ran very rich. I gave the suspect sensor a really good clean (WD40/ contactcleaner etc) and the problem seems to have gone away.

Book says that they cannot be cleaned, but if it was knackered I had nothing to loose.
 
hatzyian said:
Just for info.

After alot of swapping things, the problem seemed to be one Lamda sensor. If I swapped it to different sides, that side ran very rich. I gave the suspect sensor a really good clean (WD40/ contactcleaner etc) and the problem seems to have gone away.

Book says that they cannot be cleaned, but if it was knackered I had nothing to loose.
Click to expand...

Thanks for posting and for the helpful replies. Lumpy running can be a nightmare to sort out if you have just basic mechanical skills and this post has been really informative.

Bookmarked !:thumb2
 
+1 for that, great to have a run down of how you hopefully fixed the problem, especially as I run an 08 GS myself. Could I ask what mileage you have on the bike please?
 
Hmm. I currently have *exactly* the same symptoms (even down to the lumpy idle that kicks in about 30 seconds after a cold start) on my 2011 twin cam. Dealer has been investigating for a week now without resolution. I'll maybe show them this thread - although I can't believe they haven't tried these suggestions already.


---
I am here: http://tapatalk.com/map.php?qcjlwg
 
Just be aware that the Lambda sensor which turned out to be the poster's actual problem, will not show up on the diagnostics system if it is just returning an incorrect measurement, hence a dealer might not find it just by hooking up their computer. Might be more obvious if they swap the sensor from one side to the other.

My '08 did the same as the original poster's which is why I mentioned it earlier in this thread. Dealer kept my bike for a week to find it at the time (although how quickly in that week they actually found it I can't remember.)

Oh and if you did see my earlier post, I mentioned the TPS as well, that was not something I had a problem with on my GS, but it was the cause of similar symptoms on my R1100S.
 
might sound silly

it's ok guessing this that and the other

did you fill up with some crap petrol it does happen every now and again
also petrol stations have been known to getting wrong fuel in wrong tank s
before spending silly money drop the fuel and try some fresh
:beerjug:
 
iftikartaxis said:
it's ok guessing this that and the other

did you fill up with some crap petrol it does happen every now and again
also petrol stations have been known to getting wrong fuel in wrong tank s
before spending silly money drop the fuel and try some fresh
:beerjug:
Click to expand...

Good point - but mine has been exhibiting the symptoms for several fill-ups, from different petrol stations in different parts of the country so I'm reasonably confident that isn't the issue.

I haven't been standing over the mechanics while they investigate this issue, but IWHT swapping out the lambda sensors would be an easy first thing to try once they had tried the obvious "reset and set everything up from scratch" approach that they say they have done.
 
Thanks hatzyian

My 08 1200gs (58000 miles) had the same symptons. Started running rough and fuel consumption twice as much as it should have been, WTF.

Checked the lambda sensors, RH side very sooty. Tried cleaning, still running bad (25 mpg and not wanting to idle, very lumpy running). Purchased a new lambda sensor and installed on the RHS.

Running great now, my gs is well again :bounce1. So thanks again for the info hatzyian :clap
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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