Idel rough strange attitude.

[Valken]

Hi everybody.
On my 1200GS 2007 the idle is not very smooth.
For instance, it's a bit rough.
My mechanic showed me that if we unplug the injection of one cylinder and plug it again, the idle goes very smooth and then goes rough again.

My biggest clue is to check the spark plug cap.

Any of you have any other clue?

Regards

[pdxrmccgs]

The rough idle guessing game.

1. Coil or plug as you indicated.

2. Air or vacuum leaks in throttle body.

3. Dirt in fuel injector stopping pintle from closing.

4. Throttle bodies out of balance.

5. Phase seperated ethonal/gas leaving/dropping water.

6. Some guys have reported having the dealer do an
ECU idle map upgrade and solving the problem.

The GS 911 should show any coil/plug problem.

Let us know what you find out.

[Valken]

Thank a lot for your answer.

1. Coil or plug as you indicated.

I do not think so since the GS 911 didn't find anything.


2. Air or vacuum leaks in throttle body.

I do not think so since the motorbike is going very very well on mid and high rpm.

3. Dirt in fuel injector stopping pintle from closing.

Probably! (I had bad fuel while in Russia)

4. Throttle bodies out of balance.

We checked the balance. It's well balanced.

5. Phase seperated ethonal/gas leaving/dropping water.

Perhaps. How can I check/correct?

6. Some guys have reported having the dealer do an
ECU idle map upgrade and solving the problem.

Could also be this.

Thank

[pdxrmccgs]

Ethanol/ water...after review probably not as it would show on
both cylinders.

The CPU is a head scratch...somewhere it is written that for
eco stuff when the throttle is shut from being "open" the CPU
demands very lean fuel for a couple of seconds...probably not
applicable at regular idle.

The nuclear "V" option. Valves on bad cylinder hinky or
just need adjusting. Do pressure test and listen by ear
at muffler end for leaking exhaust valve.

Hall effect sensor tweaked. ( I'm not sure if there is one for each cylinder or not.)

O2 sensor wearing out and acting sluggish on one exhaust. These are
kind of the unsung heroes of the loop and do a good job but don't
last forever. (extreme temperatures...minimal signal output)

Thanks for the feedback.

[marc]

The R12GS has an engine speed and position sensor and a camshaft position sensor. Both are connected to the BMW-K. Neither are Hall effect devices. They are Variable Reluctance (VR) devices. Hmmm, it sounds like I am repeating myself... OH, I am! http://www.r1200gs.info/forum/12675-post3.html

If either were bad I'd expect more than the idle to be rough.

[Sleepy]

O2 sensor on cylinder you are disconnecting injector.