R1200GS won't run over 25% throttle opening.

52blackshadow

52blackshadow

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More problems with my 2004 1200GS. It missfires and won't run cleanly. If the throttle is opened past 25% ish it bogs down and all power disappears. The plugs (brisk - 50k miles on them) looked pretty burned up so I've fitted a new set, which make no difference.

When it is running, if I remove the electrical connector from the right hand fuel injector the engine splutters and dies, if I remove the left side connector the tickover doesn't change. I tried swapping the main coils over from side to side and this didn't make any difference. I then tried swapping the secondary coils over and it doesn't seem to make any difference either (still dies if the right hand injector is disconnected).

Has anyone any suggestions? The bike has done just approaching 90k miles (but seems to spend more time off the road waiting for various things to be fixed than being ridden).

To try to be clearer about the problem, if I don't open the throttle past about 1/4 open it seems to run fine, but if I open it past that point when under load it feels like the engine has died (no power). If I try to rev it up when in neutral the revs get to about 3 k to 3.5 K revs then start to miss badly, with occasional backfires. I'm trying to avoid spending too much on this because the bike has been the worst purchase I've ever made (6 years of regular breakdowns has finally taken it's toll and I'm seriously considering scrapping the thing and just sticking to my old R1100GS instead).

One desperate R1200GS owner!

Cheers, Keith.
 
Hi Keith, Might be worth just checking it's health with a compression check and compare pot to pot.
 
52blackshadow said:
More problems with my 2004 1200GS. It missfires and won't run cleanly. If the throttle is opened past 25% ish it bogs down and all power disappears. The plugs (brisk - 50k miles on them) looked pretty burned up so I've fitted a new set, which make no difference.

When it is running, if I remove the electrical connector from the right hand fuel injector the engine splutters and dies, if I remove the left side connector the tickover doesn't change. I tried swapping the main coils over from side to side and this didn't make any difference. I then tried swapping the secondary coils over and it doesn't seem to make any difference either (still dies if the right hand injector is disconnected).

Has anyone any suggestions? The bike has done just approaching 90k miles (but seems to spend more time off the road waiting for various things to be fixed than being ridden).







To try to be clearer about the problem, if I don't open the throttle past about 1/4 open it seems to run fine, but if I open it past that point when under load it feels like the engine has died (no power). If I try to rev it up when in neutral the revs get to about 3 k to 3.5 K revs then start to miss badly, with occasional backfires. I'm trying to avoid spending too much on this because the bike has been the worst purchase I've ever made (6 years of regular breakdowns has finally taken it's toll and I'm seriously considering scrapping the thing and just sticking to my old R1100GS instead).

One desperate R1200GS owner!

Cheers, Keith.
Click to expand...

is it the same when engine cold or hot?

has bike had any work recently? tank off? jet wash? are throttle cables ok?

the injector check suggests it might be worth swapping them over, maybe the LH one is duff
 
My money is on a Lambda sensor. (after the fundamentals like compression/sparks/fuel supply have been verified)

Try swapping them over and see if the problem swaps side
 
Not necessarily un-FPC related

Rasher said:
I think both cyclinders run on fuel :blast
Click to expand...

Could still be the FPC, maybe?

My 2004 1200 GS (52k miles) had similar sounding symptoms. It was definitely running on one when first started one night 3-4 weeks ago when due to go home from work. Wouldn't rev, wouldn't pick up cleanly at all. But then all of a sudden settled down and was ok for a few days, then did it again at home and didn't settle down. Didn't bother with any of the swapping stuff from side to side as described, as inherited a spare FPC when purchased the bike. Easy option was to throw that on and see. Been fine ever since, so unless coincidental and it's waiting to surprise me again one day, the new FPC did the trick

But if you don't have a spare one to try, I appreciate that it's not an easy/cheap experiment.

Neil
 
Neil A said:
Could still be the FPC, maybe?

My 2004 1200 GS (52k miles) had similar sounding symptoms. It was definitely running on one when first started one night 3-4 weeks ago when due to go home from work. Wouldn't rev, wouldn't pick up cleanly at all. But then all of a sudden settled down and was ok for a few days, then did it again at home and didn't settle down. Didn't bother with any of the swapping stuff from side to side as described, as inherited a spare FPC when purchased the bike. Easy option was to throw that on and see. Been fine ever since, so unless coincidental and it's waiting to surprise me again one day, the new FPC did the trick

But if you don't have a spare one to try, I appreciate that it's not an easy/cheap experiment.

Neil
Click to expand...

Read the post

He has determined that it runs fine on one cylinder and not on the other.:blast

Does each cylinder have a separate fuel controller - errr I think not. Therefore it has to be a component NOT common to both cylinders
 
Well....

karlp said:
Read the post

He has determined that it runs fine on one cylinder and not on the other.:blast

Does each cylinder have a separate fuel controller - errr I think not. Therefore it has to be a component NOT common to both cylinders
Click to expand...

What I've always liked about this site was that people tried to help me when I posted a query and I appreciated it.

So I offered up my contribution, based on my experience. After reading the original post. My bike was running on one intermittently, I replaced the FPC and it hasn't happened since. Maybe coincidence.

My experience is my experience. I had it and you didn't. Feel free to ignore it

Oh, well.....
 
Thanks..............................

Thanks for all the replies, I guess the fact that I don't have a string of identicle replies backs up my confusion.

I had only tried disconnecting the injector at tickover, so it may be that there is a secondary problem causing the tickover on the LHS to die, but under load at higher RPM both sides could be dying (I know when it dies under power there isn't less power, but none at all) so perhaps it could be the fuel controller (unfortunately I don't have one to try replacing it). Don't suppose anyone near Towcester would allow me to swap their FPC into my bike to try it? (in return for a beer or two).

I don't know what the HES is?

It sounds like I need to pay my friendly dealer a visit and pay them some beer tokens to plug in the Diagnostic machine?

Appreciate all your efforts!

Keith.
 
Not being there and seeing or touching it's difficult but there are easy things to try

Swap the injectors over does the fault move too? If so duff injector

Disconnect both Lamda probes under the cylinder heads that will put the ECU to a default get you home mapping and eliminates the lamda's influence on the fuelling although it should only "influence" when at working temp) Fault cured? Then it's probably a Lamda

A duff FPC could be reducing the pressure in the rail therefore not recovering before the next injector crack "Possibly/maybe"

HES will not be applicable in this instance as you have a 1200 and they have a crack position sensor Much better design that the HES certainly a lot more durable and less susceptible to heat and current surge




52blackshadow said:
Thanks for all the replies, I guess the fact that I don't have a string of identicle replies backs up my confusion.

I had only tried disconnecting the injector at tickover, so it may be that there is a secondary problem causing the tickover on the LHS to die, but under load at higher RPM both sides could be dying (I know when it dies under power there isn't less power, but none at all) so perhaps it could be the fuel controller (unfortunately I don't have one to try replacing it). Don't suppose anyone near Towcester would allow me to swap their FPC into my bike to try it? (in return for a beer or two).

I don't know what the HES is?

It sounds like I need to pay my friendly dealer a visit and pay them some beer tokens to plug in the Diagnostic machine?

Appreciate all your efforts!

Keith.
Click to expand...

tw99 said:
HES == Hall Effect Sensor - measures crankshaft position.
Click to expand...
Not applicable to 1200 versions (except the 4 valve R1200C/ CL which has them)
 
Finally found time...................

Finally found time to have a look at the 1200GS. When throttle is opened past about 25% bike pops and bangs really badly. I also think the disconnecting the injectors was a bit missleading. Disconnecting either side seems to cause a missfire.

Tried taking out the FPC and hardwiring to the battery - made absolutely no difference. I then tried disconnecting the Lambda sensors on both sides. Again, didn't make much difference.

I disconnected the TPS and the engine cut out (obvious it would really). Both Plugs have been replaced on each side with new Brisk plugs. Engine runs fine on small throttle openings, including reving right up when under light or no load (if it was ignition related i'd have expected a missfire at higher revs?)

Suspect it may be the TPS. Is there an easy way to check this? (perhaps resistance values through the range of movement?).

Beginning to really hate this BMW - Perhaps time to go back to an 1100 / 1150, or even an airhead.

All help appreciated, Keith.
 
Your not alone on this one Keith. Mine is doing the exact same thing. I'd not been able to use mine for 4 months and it just happened during the lay off. 1st time I started it it ran like crap popping etc and has not improved..... Gonna stick it in the dealers next week. I'll let you know the findings to see if it matches with your fault.

Mark
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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