Idle speed 3k-4k rpm at times. I have a 1996 FLHTCUI with 58,000 miles on it. It was running fine till the speedometer cable broke. 20 or so miles after the cable broke are when the other trouble started. I backed off the throttle the rpm stayed between 3k-4k. When I throttle up it would spit back though the intake and then go on. Backed off the throttle it would stay 3k-4k If I pull the clutch and flit the kill switch to off and coast for a little ways, then flit the kill switch back on and let out the clutch to start back up, 90% of the time it will run and idle like it should. It may run fine for 20 miles or it may act up within ½ mile you never know how far you may go.

I replaced the cable so now the speedometer and the cruise are working, I have not found a shorted wire or plug so far. I have disconnected battery to try and clear any error codes that may be stored. I have sprayed wd40 looking for intake leaks. Has anyone had this trouble before??? I have not found anyone by using the search.
Thanks

 

Sounds like you may have the trottle blade or idle air control motor (IAC) sticking or defective. When you turn off the engine with kill switch, this resets the IAC to a predetermined step position. However, if the ECM commands the IAC to do steps and it does not, the ECM loses track of where it is so you have to turn it off and start all over again. A carb cleaner is normally whats used to clean them if dirty, may have to pull it out to do it. If you want to be able to ride it temporaily without the problem, start your engine and let it idleatnormal operating temp. Then unplug the IAC. This may causea serveng lite and you will not have a fast idle during warm-up but it beats 3-4K unexpectantly, until you find problem.

 

you didn't state if you are carb or fuel Injected.
In either case.
Make sure both throttle cables move freely and the thrttle blade (in carb or throttle body)
closes correctly.
The problem could be connected to cable break or just pure chance.
I had similar problem once.
Look very closely where throttle cables connect to the carb or throttle body.
I had a small piece of gravel wedge in there, every once in a while it would roll up when I
throttled up. Then wedge and stick.
If fuelly. Then check what the other guy said. IAC motor can stick.
computers can do funny things.
Also the cruise control relies on speedometer signal for operation. so if it is geting a faulty signal
from it, it could cause problem.
good luck

 

Thanks for the info guys, i'll check those out.
Sorry it's fuel Injected.

 

A 1996 Ultra is has an ISC which operates completely differently than an IAC in a Delphi.THey are not cleaner with Carb cleaner. However, the problem may be the ISC is sticking or a wire to is has a problem.

 

ISC...Idle Speed Control?? Can you give us more, now thatyou haveour attention?

 

I fully understand this, theyoperate externally with the throttle blade, but carb cleaner is one of several cleaners that cancleanits operating shaft. He probably has one of four problems, ECM'sIACdriver bad, harness/plug, IAC motor orbinding/sticky movement ofIAC mechanicaloperating assembly, usually the latter.

 

If you understand, why do you keep telling him there is an IAC when there physically isn't one. On a Marelli system, the most common physical problems of high idle are a bad ISC motor or a nut loose on the end of the shaft. Obviously you wold check connector integrity as well as for a broken wire inside the insulation where it goes into the connector. The electrical causes are usually related to someone plating with the idle and not resetting the base voltages by pulling fuses. If this behicle has the ISC motor that has a large tip (about 1/2" in diameter) at the end of the ISC shaft, I would update it to the most current version without hesitation.

 

ok guys, i am new to this forum... searched and found it out of NEED!!!
i am new to touring bikes
i have owned, or been part owner of sportsters since i started riding....
which has only been 5 years or so.
Well my wife and i traded up, so we thouht to a
96 electraglide ultra classic
mine, once it warms up, it will only run at 3k to 4 k rpms.... its kinda scary....
you pull in the clutch, and it ramps right up to a serious high idle.
Mine is the fuel injected version.
It is completely stock, no screamin eagle parts... factory pipes etc.
I took it to the dealer and they said it was broke wires, fixed it free... when i rode it home.. same thing happened.. they essentially did nothing...
I see you guys talking about ecms and all kinds of other sensors.
what ae they, where are they?
what can i do?
First i know i need a repair manual.
They bike is going back to the dealer, but i dont have faith in them, and i live over an hour away from them. I wont be cruising on a bike every other day for them to look at and do nothing about at the clip of a week each time.
I know i have 3 sensors in my throttle body.... should i start with changing them?
What are the 3?
Could it be connected with the cruise?
Also i seen a post about pulling fuses instead of the battery tot reset evevrything...
Pull the fuses while the battery is still hoooked up, right?
which fuses?
All of them???

Also, i know about batteries...
but is it normal, for when my bike is running normal, for my battery gauge, to be charging at 10.5 amps?
when i am riding and on the throttle, it is close to a normal 14 amps....
could any of that beconnected with my idle problem....
i aPpreciate any and all info that i may receive from everyone here..

Rick

 

This is getting to be a real confusing thread and I am unintentionally doing my share to help with this. One_Screamin_Eagle and I are talking about the same motor, just different terminology, I called it an IAC motor (idle air control) and he is calling it an ISC motor (idle speed control), they bothare amotor that controls the amount of air for engine idle speed. I am used to talking to techs that call it either because different ECM manufacturers refer to it by different names, but I'll give OSE the benefit of the doubt because I don't have the manual in front of me to seewhich oneMagnetti Marelli called it back in '96', sorry about that OSE.I assumeKodd andrlowride is the same person. When Kodd/rlowride states amps, I'm assuminghe means volts from the volt guage.

I should have caught this the first time aroundbutwe should not be troubleshooting your idle or anyEFI (electronic fuel injection) problems until we know thatthe voltage to it iscorrect, otherwise we could start running in circles. Even if a dealer is weakdiagnosing EFI problems, they should be good at fixing Harley charging system failures, alternator, regulator or wiring, get that fixed first, then if you still have a problem we'll do our best to try to help. If you are unconfortable with that dealer, isn't there any good independents around their, where the best techs for older bikes usually reside?