Question about 2008 Harley Davidson FLTR Road Glide

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Idle fluctuates on cold start - 2008 Harley Road Glide

On cold start, idle fluctuates 1,500 rpm's down to 1,000 rpm's and back up again. It does that for about a minute, but if seems like it's almost ready to stall out when it drops down to 1,000 rpm's, but it doesn't. After a minute, it smooths out and is fine.

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Sounds like you have a vacuum leak. that is where i would start. other then that i would start checking sensors.

Posted on Jun 08, 2014


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Posted on Jan 02, 2017

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if it is open loop ( O2 sensors) check the sensor condotion, connections etc.

Reload the files onto the Power Commander, insure they are the exact files for your ride, the wrong files can affect operation and gum up the O2 sensors.

Posted on Apr 13, 2009

  • 284 Answers

SOURCE: speedometer cable 1998 Harley Road Glide

There is a little set screw that stops it from coming out. remove the set screw then I believe you have to unscrew it.

Posted on Jun 27, 2009

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SOURCE: 2002 Dyna wide glide. Will not IDLE

not running for a year! You have a varnish buildup in the low end circuit of the carb. You will need to remove the carb and do a full teardown of the carb to properly rectify this problem. SOMETIMES we are able to free up the passages by putting SEA FOAM cleaner in the tank , fill her up with fresh fuel and ride through the tank and it will clear up. SEA FOAM can be purchased at an auto parts store and is sometimes very effective. 1/4 cup to full tank fuel.

Posted on Jul 14, 2009

  • 5 Answers

SOURCE: Idling high

Your sucking in air on the induction circuit somewhere. Probably a split in a pipe around the carbs. This leans out te mixture and raises the revs.

Posted on Jul 25, 2009

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SOURCE: 2003 harley davidson heritage springer


Posted on Nov 08, 2009

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Related Questions:

1 Answer

What controls the Throttle on cold startup?

The onboard computer (ECM) sends a signal to the throttle body to enrich the mixture, and kick up the idle speed when doing a cold start.

Jun 12, 2014 | 2008 Harley Davidson FLTR Road Glide

1 Answer

Fluctuating cold idle - 2008 Road Glide

Try this:
Turn kill switch to ON/RUN position.Cycle the ignition(key) switch 4 times (each time long enough for engine light to go out ~15 seconds).
This resets the "zero" position of the Throttle for the ECM.

May 17, 2014 | 2008 Harley Davidson FLTR Road Glide

1 Answer

Idle fluctuates on cold start - 2008 Harley Road Glide

This is H-D tech bulletin on the issue:

TT380 - June 12, 2008 - High Idle Complaints on 2008 Touring Models
High Idle Complaints on 2008 Touring Models
Due to '08 Electronic Throttle Control calibration strategy parameters and throttle gripsensor
variability some customers have experienced intermittent changes in idle RPMs. This
condition is caused by a change in the zero position stored to memory in the ECM, as
determined by the last four readings seen at key OFF. This cannot increase engine speed
while riding but would change the idle RPM, similar to adjusting the throttle stop screwon a
carbureted model.
To correct this condition we will be making several changes to the throttle gripsensor to
reduce voltage variances and also update the way the calibration's strategy looks at and
records these voltages. Completion of these changes and test validation will take several
In the interim we have released revised calibrations in the latest version of Digital Techto
alleviate the high idle concerns for those customers experiencing the condition. The current
software version (1.004.001) and details of the changes can be viewed by selecting the
What's New button on the home screen of DTII. This info is also on h-dnet under:
Service>Tools & Equipment Info>DTII>Version Updates-What's New. The new calibrations
will leave the ECM powered up for 10 seconds after key OFF to complete housekeeping,
allowing the rider more opportunity to release the throttle grip, so the throttle control can
return to true zero before the ECM poweris shutdown. This should eliminate rider induced
zeroing issues. Additionally, the new calibrations will be less sensitive to voltage changes due
to an increased dead-band in the operating strategy. Under certain conditions and riding
styles some customers may notice a slightly different throttle feel, or comment on reduced
engine responsiveness. This is due to the increased dead-band and will feel similar to a loose
throttle cableadjustment on non-ETC vehicles.
Therefore, we recommend only reflashing vehicles for customers experiencing the high idle
concern and wait for the next version calibrations before updating vehicles on a wider scale.
SE Race Tunerand SE Super Tunercalibrations have not been updated at this time, and
reflashing a stock cal over a Tuner cal may only temporarily alleviate the high idle, until you
reflash back to a tuner cal.
It is recommended anytime you replace ECM, TGS or Reflash the calibration to cycle the Ign.
switch 4times, waiting 10 full seconds after keying off between cycles, to relearn zero TGS
The following warranty credit procedures will apply to domestic dealers only:
Warranty credit will be allowed for reflashing the calibration at the usual rate.
For OE calibrations including CVO, file an MC claim using labor code 7804 for 0.2 hours
For SWR'ed P&A calibrations, file a PNA claim using labor code 8209 for 0.2 hours labor.
Non-registered P&A performance calibrations will require preauthorization for warranty credit.
NOTE: Labor code 8209 is a new code and may need to be downloaded into your system

May 17, 2014 | 2008 Harley Davidson FLTR Road Glide

1 Answer

06 street glide dying until warmed up

Your cold idle setting is wrong. You need to adjust that a bit higher. When your scoot warms up, it will drop back to your warm idle setting.
Go here and read

Semper Fi,

Jan 31, 2018 | Motorcycles

1 Answer

2003 HD Road King - starts fine, idle normal. Once it is warm, idles at 2000 rpm. Does not come back down, even after riding for an hour or two. Only idles normal when cold. Help??

If you bike is equipped with a carburetor, the idle stop screw is located at the top of the carb on the right side. Counterclockwise turn slows the idle speed.

If you bike is fuel injected, a dealer or shop will have to set the idle speed electronically.

Good Luck

Sep 16, 2010 | 2003 Harley Davidson FLHRCI Road King...

1 Answer

I have a 2008 ultra classic all of a suden when you start it idle is high 20 thosand rpm any thing i can try befor . thaking it to the dealer. thanks rick e.

20 thousand rpm? I don't think so. Obviously you're reading the tachometer wrong. It may be idling at 2000 rpm. I agree that this cold start fast idle is a bit high for me as well. You have no choice but to take it to a dealer or an independent dealer that can change the setting in the fuel control computer for the cold start fast idle speed. There is nothing that is "user controllable" on the late model's fuel control system. Sorry.

Good Luck

May 27, 2010 | 2008 Harley Davidson FLHX Street Glide

1 Answer

Idling high

Your sucking in air on the induction circuit somewhere. Probably a split in a pipe around the carbs. This leans out te mixture and raises the revs.

Jul 21, 2009 | 2008 Harley Davidson FLHX Street Glide

1 Answer

When I start my Harley-Davidson the RPMs jump up and stick. What is wrong?

May be normal. When cold ,the bike should idle fast for a few minutes. If started hot, will idle fast for a few seconds. Cold idle should not exceed approximately 1800 rpm.

May 09, 2009 | 2002 Harley Davidson FLHTCUI Electra Glide...

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