Fluctuating idle only in gear at stop

[Eli355]

I have search but not fount this. At a stop, in gear with clutch in, idle fluctuated between 1000 and 1400. Like pulsing. If I sit in neutral it is steady as a rock. If I come to a stop and go right into first it idles high and fluctuates. If I hit nuetral it sits rock solid at the light. Any ideas

[GT-Rx]

This will be virtually impossible to diagnose via the net, but It's clearly load based so some disassembly investigation is in order. Which model? Under warranty?

[pete roper]

While it does sound load related it may also be simply that both your air bleeds are open and the TB's aren't ballanced. Make sure it is correctly tuned and the TPS is set right before you panic.

Pete

[misterg]

My '08 Norge exhibits this same behavior. Pop it into neutral as you approach a stop sign or red light, and the idle is steady. With clutch pulled in, idle will rise a couple hundred RPM on occasion. Not constantly.

Can't imagine that it's a case of the clutch not fully disengaging, as the lever requires only an inch of travel, at most, to disengage the trans...

[kiwi dave]

I'm guessing that it could be the stepper motor, which might be programmed to act more aggressively when the bike is in gear?

If this still happens and you've got the stepper motor bypass kit, all bets are off.

[Rafael]

Here are my two cents: As far as I know, the stepper motor only operates during the closed loop just after start up. The lower/normal idle speed, clutch engaged, is probably due to the motor turning the clutch shaft in the gear box oil. The reason the idle fluctuates with the clutch disengaged, is the extra air is getting into the intake raising the idle speed and the ECU trying to getting it back down to spec. Most likely the second bypass screw is open. After your bike is properly tuned and if it's still misbehaving, I'd check the idle stop screw. This screw is set at the factory and should not be adjusted. Both times (B11 & Stelvio) I've seen an irregular idle it's been the idle set screw setting was changed. On the stelvio it was adjusted by an unknowing authorized MG shop and the B11 adjusted screw was revealed when the map was updated.

All draw bands on the intake should be snug too. Stepper motor hoses - the same.

[Eli355]

Thanks for the responses. Tomorrow I will try clutch in and neutral. My guess is it is not the clutch in that creates the issue but is the transmission in first gear. Would that make a difference to you diagnosticians?

[JAS]

This is a common problem with the 1200 2v engines.

I have a GuzziTech ECU (no closed loop circuit) with the throttle bodies correctly adjusted (only one bleed screw open), the TPS reset and the throttle stop has not been touched (I have owned the bike since new and have done all the servicing), and still experience the problem, especially during hot ambient temperatures.

I suspect that this issue is related either to an ECU sensor tolerance (engine speed, intake temp etc) or maybe the stepper motor / ECU is a problem, however there are no ECU errors that come up. The bike has had this problem since new.

Is this a new problem or has the bike behaved like this since new? Also, when you turn the ignition off, does the stepper motor make a humming noise and a few clicking noises (mine does)?

Jason

[GT-Rx]

ECU programming is the same across the board for all of the motors/bikes, and has one switch/duration for the stepper/idle motor; oil temp. On or off.

[misterg]

ECU programming is the same across the board for all of the motors/bikes, and has one switch/duration for the stepper/idle motor; oil temp. On or off.

OK Todd, but I assume --since many have had luck fixing this problem with the stepper motor defeated-- that's not the whole story on the stepper motor, right? Does it actuate despite the oil temp being above the shutoff point?