BMW R1200RT/R1250RT Forum

hello everyone

I have a 2011 R1200RT, it hasn't been running for 1 year and now when I start it the engine is unstable.

Here are the symptoms, the idle is stable but when I touch the gas pedal even a little bit, the engine accelerates quite strongly (3 or 4000 rpm) then slowly goes down to idle.

I plugged in an OBD2, then with BMW MOTORSCAN I could see that there was a fault on the exhaust valve.
I dismantled it and it's stuck in the fully open position, which shouldn't cause any operating problems.

I then balanced the cylinders, locking the idle motors, and in this case I was able to eliminate the engine acceleration problem. However, as soon as I put the idle motors back on, the problem started again (unstable engine acceleration as soon as I touched the throttle).

I've also checked the throttle position sensor, which works normally.

Additional information:
if I disable the idle stepper motors with motorscan, and then disconnect them, everything works normally.
however, as soon as I connect one or other of the idle stepper motors, the problem appears.

Do you have any idea what the problem is?
Thank you

Could the problem be the stepper motors themselves, viewtopic.php?t=4668

Once upon a time I had something like this happen to me; turns out the cable from the cruise control module to the throttle was not correctly routed and this caused the engine to rev uncontrollably.

hello everyone,

I performed the following tests:
- TPS sensor: OK
- 2 x idle stepper motors OK
- Cleaning of the entire intake assembly OK
- Temperature and air pressure sensors give correct information with MotorScan
- Cylinder synchronization OK

Symptoms:
- At start-up: the engine rises to 2000 rpm then falls back gently to 1000 rpm.
- If I accelerate just a little, the engine instantly climbs to 3000 rpm, then when I let go of the gas pedal it drops back to 1000 rpm very slowly
- If, once at idle, I disconnect the 2 idle stepper motors, everything works normally again, acceleration is again perfectly controllable and regular, and when I let go of the gas pedal it immediately drops back to idle speed.
- if I reconnect the 2 stepper motors (or even just 1), the problem starts all over again.

Isn't there another sensor that manages the position of the idle stepper motors ?

Thanks for your ideas.

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