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Up Topic Open Technical Section / C1 Technical Chat / Stalling at low revs
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- - By aware Date 28-08-2010 15:42
After some "nice" jet washing of the bike, there seems to be some stalling at low revs (I believe between 200-800 rpm).
Idle is perfect. While stalling the dash lights remain intact which means that this isn't a power issue but mostly a ECU or fuel injection as far as I understand.
At mid to high revs the bike behaves as usual.

Any ideas and comments more than appreciated.
Parent - By bolt-on-billy Date 29-08-2010 14:57
does it stall on idle if you leave it? if so then you have a tight valve. if its stalling on slowing down then it can be valve or wonky lambda readings  the lattter might mean an ecu remapping at a bmw dealer the former would be valve check and adjustment.

not sure where the jet washing comes in but other possible causes are wet electrics, broken injector wiring or ignition trigger, loose spark plug/bad ht cap.
Parent - - By Gerona-bike Date 29-08-2010 20:23
A triffle late now, but the BMW C1 owners manual strictly forbids power washing precisely because it can cause damage to the bike, further it even discourages the use of a hose.  The revs you quote would be idling, since at full throttle the bike would reach something like 9000 rpm and I do not see the bike running at 200 rpm at all as idle would be much higher than this.  I presume that under the circumstances you have checked the ignition side and injector signal wiring for damp.
Parent - - By aware Date 29-08-2010 20:33
Idling is 100% faultless - there is a problem just above idling, a little throttle and the bike stalls. A little more or much more throttle and the bike is 100% faultless again.

Still clueless
Parent - - By bolt-on-billy Date 30-08-2010 00:59
try a reset. where are you?
Parent - By dobedobedo Date 25-11-2010 23:28
What's a "reset" ?
Parent - - By Drynotwet Date 30-08-2010 02:20
I stupidly jetwashwd my big bike oncethe only way it came right again was after it was sat In a warm A dry workshop for  hours with a fan on it
Good luck!
Parent - - By aware Date 31-08-2010 08:02
I will try to reset, I will even plug the Cmon to see if something comes up. I am based in Greece!!

Now, I drive it again and again - what I notice is that the throttle when slightly open behaves like it is open/closed all the time. Imagine that you did that for fun; you for half a second open the throttle, then let it from your grip (which means it closes) for another half a second. Playing around you could do this for a long time. This is EXACTLY what I feel the bike does while I slightly open the throttle. It seems to be so close to the closed position that it just moves in between the closed and slightly open...

Still clueless and closest BMW dealer is 150 kms away.... What a pitty
Parent - - By bolt-on-billy Date 31-08-2010 13:16
see what faults the cmon comes up with and reset the tuning, also try a reset and running with the lambda unplugged as it will default to a slightly richer mix.

I find that on a low throttle mine loses and surges as it goes along which is strange but other bikes seem to hunt around when idle as well.
Parent - - By aware Date 17-09-2010 13:51
C'mon rules!

Injection valve (201 - S V fault). That meant that I traced the injection cable and oops the usual issue of broken cable.
It was cut at the very start and this wasn't an easy task to fix. I believe now it will be OK. I will run it for some days and keep posted this 100% useful community.

Parent - - By bolt-on-billy Date 17-09-2010 19:38
with couple of paper clips you can push out the plug tips, remove the blue bungs, and snip off the end. re solder and reassemble.

if its gone at the plug then double trace the wire back a bit and check it as its often broken in a few places
Parent - - By aware Date 18-09-2010 11:44
Great tip! I will use it if it fails again...

Parent - - By aware Date 25-11-2010 15:21

My second C1 suffered from a broken cable. I was close to home, went back, got some tools and fixed it on the spot.
Now, after this some strange thing happened:
VERY UNEVEN IDLING and some stalling at low revs...
1) I rechecked everything
2) I put a thicker cable to connect the broken part
3) I reset ECU (throttle twists)
4) I used C'mon to reset idle, throttle valve and lamda sensor
Result: Same situation, VERY UNEVEN IDLING and some stalling at low revs...
So I need to apply some throttle at traffic lights because sometimes the engine stops...

Any please? My head is  s t u c k

Parent - - By Drynotwet Date 25-11-2010 15:51
First, make sure the injector is working properly-don't assume it is because you fixed it.
Secondly, I wonder if the thicker cable might affect the resistance of the system and hence the amount of fuel injected
Parent - - By jp72 Date 25-11-2010 18:26
I'm not sure but maybe you need to trim the cable tension after replacing it ?
Parent - - By aware Date 25-11-2010 22:36
May I please ask what "trim the cable tension" is? I don't know what this is and how is done...

Parent - - By jp72 Date 26-11-2010 06:58
Look into the service manual, chapter "32 72 305 Replacing throttle cable", page 259.

There's a picture showing a fasterner/rubber cab that allows to adjust the cable length.

To set correct cable length :
- move the throttle handle all the way from minimum to maximum and ensure you hear the throttle valve 'clicking' on both ends.
- move the handlebars all the way from left to right and ensure that throttle valve does not move

I hope it'll help.

Parent - - By aware Date 26-11-2010 10:50
No, Jerome it is the injection valve electrical cable that is broken - not the throttle cable...

I posted a video of how the bike behaves:

It starts OK, then stalls more and more and eventually engine stops.
C'mon shows "injection valve error, occurs X 1"

I think I may need to swap injection valves with the other bike I have BUT:
I think this is messy and difficult since I will need to take off the pipes having lots of gas leaking out.
Also, when I will reassemble I will maybe need some new "metal collars". And definitely something more will go wrong according to Murphy's law...

What do you reckon?

Parent - By 993turbo Date 26-11-2010 14:01
Pulling out the Injector is a 2min job. Hardly any mess.

-Unplug the contact
-Unscrew the 2 screws at the top of the injector bracket
-Pull the injector up
-Undo the clip which holds the injector in the bracket.

putting it back is the opposite :-)

Hardly any spill, and no need to undo the hoses.

And you are done.
Parent - - By Drynotwet Date 26-11-2010 14:31
That's sudden death.
First thought is fuel pressure
Is the fuel pump running ok?
It pressurizes at start up, so perhaps you'd bike uses that pressure then dies.
Parent - - By aware Date 26-11-2010 15:33
Parent - By 993turbo Date 26-11-2010 15:46
Fuel Pump is a 10min job.

In this job it is impossible to avoid ''some'' petrol spill. But its not too much. No worries.

Do the following:

-Unplug the connector
-Undo the hose clamps (2 of them) at the pump side. (for re-assembly you will need 2 new ones, I use the screw type, as they can be reused)
-Pull off the hoses from the pump unit (2 of them)
-Unscrew the BIG ''nut'' which holds the pump assembly in place. Here you can use a flat screwdriver with a hammer as you ''special'' tool. Simple give it a few taps til it comes loose. Unscrew it, and watch the gasket :-)
-Pull the pump / level indicator out. This requires some fiddling......... :-)
Parent - - By jp72 Date 26-11-2010 14:10
Oops !
I complety misunderstood this thread, sorry :(
Parent - - By aware Date 27-11-2010 00:22
Thanks for the instructions - So I will first try to swap injection valves.

If I need also to swap fuel pumps, this is a different story.
I read the service booklet and I can see that it needs hose clamps to stop leakage and some special tool to undo the fuel pump...
Parent - - By aware Date 28-11-2010 19:23
I swapped injectors, no difference.
So problem is somewhere else.

Some history:
Bike performed ok. Sometime (5.000 kms ago) I noticed some very rare misfires, especially when throttling from standstill.
One day, as soon as I arrived home, engine stopped. Then it worked again after some persistent attempts to re-ignite.
Next day, I drove and engine stopped with no re-ignition possible. I found broken injector cable, fixed it and then the bike behaves as shown on the above posted youtube link.

Can it be fuel pump? Is it hard to swap?

What else do you believe it can be?...

Parent - - By Drynotwet Date 29-11-2010 00:26 Edited 29-11-2010 13:03
Have you checked that your fixed injector wiring is fixed?

I wnt bore you with my not/fixed brake  story just trust me. Check the fix, don't assume,because it does still sound like a faulty injector and the most likely reason is (edit) broken (edit) wiring
Parent - - By aware Date 30-11-2010 09:44
Played more with swapping injectors (that's the magic of having 2 C1's!)
-Let's call the probably defective injector "suspicious"
-Let's call the other one"normal"
When suspicious injector plugged on other bike, I can definitely see problems such as stalling and weak performance. However, not the bad behavior on other bike that was full of misfires and the engine eventually stopped working

When normal injector plugged on the other bike, I can see substantial improvement; the engine never stops working and the times it has uneven idling is much better than with suspicious injector...

My conclusion:
Suspicious injector: most probably defective
Normal injector: was ok on other bike, now behaves strangely on the bike it had problem. I expected it to be 100% smooth and not a bit defective too..

What do you reckon?

PS: I performed "engine tuning tasks" with C'mon device after swapping injectors
Parent - - By jp72 Date 30-11-2010 10:24
Do you have the same ECU software version on both bikes ?

The v8000 is known to better handle stalling / idle problems.

If versions are different, you could try to swap the ECUs as well :)
Parent - - By aware Date 30-11-2010 22:56
The problem is that now I have 2 problematic bikes instead of one...

I am so confused
Parent - - By jp72 Date 01-12-2010 07:04
Check the ECU versions, I can reprogram it for you to v8000
Parent - - By 993turbo Date 01-12-2010 07:58
is this the ''latest'' ECU update? You should program this feature into your MT1..... :-)
Parent - By jp72 Date 01-12-2010 08:40
Yes it is the latest. I had the same stalling problems with one of my C1, it was coded with v7000. I upgraded it to v8000 and now it runs like a charm.
I could implement the upgrade feature  into the MT1 if I could break the ECU security protections... Not impossible, but not obvious as well... I have other priorities at the moment. :)
Parent - - By toby_holland Date 02-12-2010 06:50
hello jp72,
how can i get you to do this to mine? post you the ECU?
c'mon said i'm running 7000, and the update sounds desireable.
Parent - - By jp72 Date 02-12-2010 08:18
Please PM me, I will send you my personal address for you to post the ECU. Please be aware this is done at your own risk, I will take no responsability if the ECU is lost or for any issues you would encounter with that operation :)
Parent - - By aware Date 02-12-2010 23:06
The problem persists and I start feeling bad.
The engine stalls at low revs and I can even smell that the combustion is not complete.

I will need to re-swap injection valves to possibly come to a reasonable conclusion.
The bikes are at least driveable but I hate BMW for doing such a poor job.
Parent - - By jp72 Date 03-12-2010 07:14
I'm not that surprised that both bikes don't run smoothly. You said you reset the valve adaptation values after the swap (and that a correct operation) with your C'MON. In that case the ECU needs to re-learn the new probes, I don't know how long it takes, but in that case maybe you need to test drive the bike a few kilometers to help in that process. In my opinion that would explain the combustion problem. By the way you did not answer my last question, what is your ECU versions ? :)
Parent - - By aware Date 03-12-2010 11:55
The version is 8000.
I am so confused:
1) The C'mon shows fault 110 (Intake air temperature) but this error existed 3 years now with no effect on performance.
2) No error for injection valve although the bike behaves like mad, stalling at low revs and with engine stopping at idle after some 10-20 seconds of hard idling
3) I have done many kilometers after swapping the injection valves (maybe 500km's) but still there is no improvement at all

Parent - - By jp72 Date 03-12-2010 12:45
1) Can you reset the fault 110 with your C'mon ?

   If this fault remains after reset, this could be due to a fried output on the ECU... I've got an ECU at home that have both throttle and intake I/O stage burnt....

   Maybe it would be worth swaping the ECUs...

2) Sorry to insist, but did you check that the throttle cable is well adjusted ?

  Here is a extract of BMW instructions when resetting adaptation values:

  "It is absolutely essential to adjust the throttle cable correctly so that the BMS Compact control unit
  can correctly relearn the adaptation value for throttle valve zero position after resetting.
  For this purpose, make sure that the throttle valve rests on the mechanical stop (in the idle position)
  with the handlebar turned (left and right)."
Parent - - By aware Date 03-12-2010 22:06
Why should I care about the throttle cable?
I never touched it...
Parent - - By jp72 Date 05-12-2010 08:14
Cable operation and wear can cause problems with time... At this stage I believe you need to check any option :)
Anyway, this is an easy check....
Parent - - By jp72 Date 06-12-2010 07:22
Another idea : Did you check the O-ring ?

I read that when the injection valve o-ring is not sealed correctly it can cause all sort of surging / stalling problems...
Parent - - By aware Date 07-12-2010 23:13
Latest update:
It seems that a valve is burnt since the bike idles ok when cold but becomes erratic and stalls when warm.
25000 Km's on the bike, and pretty sure never had valves checked (neither me or previous owner).

So now I maybe have two options:
1) Call BMW and ask how much money and time they need to check and fix valves (X hours and Y cost)
2) Give them the bike and let them check everything from scratch (3X hours and 3Y cost)

What would you do in my position?

Thanks in advance

PS: BTW a pipe full of oil can be seen in attached photo. Why can this be oily?
PS2: Coincidentally, some hours or days before the stalling occurred, it happened that I turned on the engine without applying the front brake. I did by accident and I was surprised. I tried it again today but it didn't work... Strange
Parent - - By 993turbo Date 08-12-2010 08:01
The pipe you are refering to is the breather pipe. This pipe transports oil vapours from the engine to the airbox....

What do you mean ''turned the engine before applying the front brake...) I always turn my engine without applying the front brake. The rear brake however must be applied to crank the engine. (sorry if I missunderstand what you are on about)

also, what is your compression?
Parent - - By aware Date 08-12-2010 09:03
Sorry I meant the rear brake (left handlebar).

Bike performs ok at high revs so compression seems good.
I haven't measured compression properly with special device...
Parent - By 993turbo Date 08-12-2010 09:12
you should meassure your compression.......
Parent - - By Andrew Date 08-12-2010 09:15
Your valves may not be burnt yet because it idles OK when cold. You need to check the valve clearances as soon as you can and avoid riding it because that will start to burn the exhaust valves.

It's usually the exhaust valve clearances which need sorting out. This means new shims - that's cheaper than new valves as well.

You can check the clearances without removing the engine, but you will need to jack or lift the bike up and release a few cable clips plus the rear shock absorbers for access. The engine swings down and there is plenty of room to work on it. The manual gives you the details. The shims can also be replaced with the engine in this position.
Parent - - By aware Date 08-12-2010 15:00
I speak about burnt valve because I read on another thread that if it stalls only when warm then it is due to the:
"The valves close ok when the engine is cold and the compression will be ok also but when it is hot the thermal expansion causes the gap to close too much so that the valve does not seat properly - once the revs are up the slight sensitivity is masked but at low revs the fuel balance is upset and the engine stalls.";hl=inject   (3rd post by john wells)

Now, I have checked once the valves on my other C1, it wasn't a piece of cake and I remember that the gasket seal didn't fit well first time so I had to re-assemble everything. And I am pretty sure the shims are impossible to change in a DIY manner. I believe it is necessary to let a BMW service center..

What do u reckon?
Parent - - By 993turbo Date 08-12-2010 19:57
chims are easy to change....... if you have some mech inclination
Parent - - By aware Date 08-12-2010 22:04
More and more I believe that this is a burned exhaust valve.
That's maybe why I can smell incomplete combustion...

Very quizzy bikes, I must say...
Parent - - By Andrew Date 09-12-2010 16:35
Once an exhaust valve is burnt you will not be able to start the engine, even from cold. That's why your bike just sounds like a tight valve clearance to me.

Shim changing is certainly possible, I've just done 3 as part of an exhaust valve replacement and I'm no trained mechanic. This c1ub gave me the confidence to try it and the information on how to do it. I had the engine out of the bike because of the amount of extra valve work required, it certainly makes the job easier.
Up Topic Open Technical Section / C1 Technical Chat / Stalling at low revs
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