Question about 2008 Harley Davidson FLTR Road Glide

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Idle fluctuates on cold start - 2008 Harley Road Glide

On cold start the engine fluctuates from 1,500 rpm's to 1,000 rpm's and back up for a minute. When it goes down, it seems like it's going to stall out, but it doesn't.

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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

Posted on Jun 18, 2014


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SOURCE: speedometer cable 1998 Harley Road Glide

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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.

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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.

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SOURCE: My check engine light goes on sometimes and then

on your dash is the button to check your milage. push it in and hold it down until your codes come up. some of the numbers it will go through will only be ecm numbers

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Testimonial: "exactly what I needed. Thanks,"

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SOURCE: i lost the key to 2008 harley road glide

Sorry,sounds like a trip to the dealer.Take your title and vin number,they'll make you another key.I think the security thing is kind of universal it programs itself somehow. Anyway,good luck.

Posted on Mar 20, 2010

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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.

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Try this:
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Idle speed around 2000 rpm, 1st ride of the year , had this issue. I followed my Manual info and adjusted Cold and Hot adjustments. When restarted the idle was close to normal, but after a minute or 2...

Adjust the idle speed ONLY when the engine is at full operating temp. It should be idled at about 1000 RPM. It will probably be too low when cold and you may have to use the throttle control to keep the engine running until it gets completely warmed up. On the carburetor equipped engines, you cannot adjust the bike where it will idle cold and not be too high when it gets hot. The only way you can get this is with fuel injected models.

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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.

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2006 harley ultra with true dual exhaust. back fire and sputteres and dies on cold start, will not idle, after running a few minutes on the road it clears up. only does it when its cold,

did you upgrade the air filter and the module for the fuel injection.the minute you change exhaust it messes up the 02 sensor,and the map readings etc.

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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.

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1990 Honda Prelude 2.0 si F.I. Idle Fluctuation

This problem is a little bit hard to coz you need to check the following throttle body, fast idle valve & the IACV valve. First the throttle body it must fully closed during idle and the TP sensor voltage must be 0.5 volt. The fast idle valve is wax type there is a 2 small hose pass below of this valve, if the coolant water is not circulating the valve will not closed. You can check it by touching the lower portion of this valve after 1 min. Regarding the IACV you can check if this is the fault by removing the hose connecting the throttle body and air filter. there is 2 small hole near the opening of the throttle body, while the engine is running at idle close one by one and see which one cause this problem.I hope this will give help to your problem.

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Honda Accord 1991 idles high then low

)The fact that thge engine idle fluctuates when it is cold indicates that the Fast Idle THermo Valve is out of adjustment.
This valve is located ot the front of the intake manifold on the driver's side just below the accelerator cable. To adjust it, wait until the engine is cold (best to do it first thing in the morning).
Remove the two screws holding the cover on and start the engine. There is a brass needle sticking up through a plastic ring that has two slots in it. With the engine idle fluctuating, use a thin flat blade screwdriver to SLOWLY turn the ring CLOCKWISE
until the idle stabilizes. Once done. put the cover back on withg the two screws and you should be done.

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