2010 Intermittant Low Idle

[kiteflyer]

This is beginning to drive me nuts. I've posted here before about my low idle and have gotten good suggestions and fixed a bad TBS job. Now the fun begins.

I have a 24 mile commute on back roads at 50 - 60 mph until I reach the Interstate and ride 75 for 7 miles to the plant I work at. For the past several rides the bike runs great until I get off the Interstate. Then, the idle drops and stumbles and I must keep revs up to keep the engine running. In the evening, it'll start right up and run just fine until I get almost home and then the same stumbling idle until I pull into the garage, To date I have added new plugs, air filter and searched for a bad vacuum hose. I have 'shocked' the fuel system by removing gas from the tank until 1 bar is showing on the gauge and adding 8 ounces of Seafoam, running the engine until warm (to get the concentrated seafoam mix into the injectors). Filled the tank up wih non-ethanol gas and let it sit over night. When started, no smoke or soot came out as I was expecting.

Occasionally the yellow engine light will come during this stumbling. No error code is displayed, just the yellow light.

I'm afraid I will have to seek out the local dealer for relief. But it was that same dealer that screwed up the TBS to begin with. Have any of you guys ever experienced or heard of these symptoms? I can't think off anything else to try.

 

[wmadoty]

While the 10's are not included in the recall, I wonder if this is a grounding issue? I hope not, as I also own a 10, but there are three or four earthing blocks "spiders" that you can get at real easy. I think you should pull the caps and take a good look at the shorting bar and terminals.

 

[Fred W]

What is the warm idle speed set to?

Set it to 1100-1200 rpm and see what happens

 

[kiteflyer]

What is the warm idle speed set to?
Set it to 1100-1200 rpm and see what happens

Warm idle is at 1100-1200. When stumbling sets in, idle drops to 40-500 rpm. The grounding spider issue is beginning to look like a reality.

 

[Fred W]

Might also want to do the TPS diagnostic when the symptoms are present (engine hot) just to be sure that isn't the culprit. Info on how to do that is available here

 

[kiteflyer]

Might also want to do the TPS diagnostic when the symptoms are present (engine hot) just to be sure that isn't the culprit. Info on how to do that is available here

Forget to mention that I have also done the TPS diagnostic.

 

[Fred W]

Might also want to do the TPS diagnostic when the symptoms are present (engine hot) just to be sure that isn't the culprit. Info on how to do that is available here

Forget to mention that I have also done the TPS diagnostic.

Did you perform that check when the engine was hot and showing the idle symptoms?

Doing it cold or when it isn't symptomatic would not show anything.

 

[kiteflyer]

Might also want to do the TPS diagnostic when the symptoms are present (engine hot) just to be sure that isn't the culprit. Info on how to do that is available here

Forget to mention that I have also done the TPS diagnostic.

Did you perform that check when the engine was hot and showing the idle symptoms?

Doing it cold or when it isn't symptomatic would not show anything.

Yes, the engine was hot. But at that time, it was idling at 1100-1200 rpm. The diag has not been run during "stumbling" idle.

 

[stanlee]

Have you added anything electrical if so unhook and see if problem goes away.

 

[kiteflyer]

I wound up taking the bike to the local dealership and they found an air pressure sensor in the intake that had developed a crack in the plastic housing causing bad readings to be sent to the ECU. A little plastic epoxy and I'm back in business.

Thanks for all the suggestions. Now I'm ready for my Alaska trip in June.

Regards,

 

[PhilJet09]

Interesting. I'm glad I found this thread as mine has started to experience similar problems. The idle is set to 1100, but occasionally goes down to 500-600. It seems to be getting worse and even stalled on me the other day. I'll look for that sensor in the intake, but can you elaborate a little more on yours? Where exactly is it? How big of a crack are we talking about?

I won't be home for a few days, so I'm trying to research as much as possible so I'll be armed and ready to tear into it when I get back.

 

[SLK50]

Yes, please share more info. Also interested.

 

[PhilJet09]

Bump

 

[stealth1]

Pictures would be nice

 

[PhilJet09]

Update: I found the sensor he's talking about and it didn't seem to be my problem. I cleaned the throttle body butterflies and did an un-authorized sync and haven't had any problems since.