Auto tune issue

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May 16, 2023 | 10:16 PM

sleighcrane

Thread Starter

Tourer

Joined: Jan 2013

Posts: 411

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From: Parksville B.C.

Auto tune issue

I have done several auto tune runs but my bike sometimes stumbles when I leave from a stop. Is this something I should be able to correct through autotune or a dyno run? Recently installed S&S 475 cam, jackpot mufflers, on a 2019 road king 107. Bike runs strong just a very occasional cough starting off. Thanks

Last edited by sleighcrane; May 16, 2023 at 10:27 PM.

May 17, 2023 | 08:52 AM

strych9

Seasoned HDF Member

Joined: Aug 2017

Posts: 7,323

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From: Omaha,NE

I don't believe auto tune would help you in that range. Sounds like you need to do some data logging to see what's causing the issue. Foremost, check the basics first. I would check my ignition wires first to make sure no spark leakage exists either along the length of the wires or at the plugs. Torn boot? Vacuum leak somewhere? Smacks of a possible misfire. If your fuel tables have smooth transitions in the areas where you have the stumble, I'd be surprised if it were a fuel issue. Good luck.

Jul 13, 2023 | 10:42 AM

sleighcrane

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Joined: Jan 2013

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From: Parksville B.C.

After several auto tune runs and another map from FM who have been very helpful I began to see a pattern develop. Bike had to be at operating temp a bit of high speed and then idling. When I would go to leave a stop was when I had the sputter. Realized that my EITMS was enabled and I believe the transition to throttle up was causing it. I have since disabled it and preliminary runs show improvement. Preference would be to get it on a dyno eventually after I find one reasonably close to home.

Jul 23, 2023 | 03:55 AM

DeeRoe

Road Warrior

Joined: Dec 2005

Posts: 1,276

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From: SE SC

So, I've found that with EITMS, if I notice it's activated at a stop light, I'll just blip the throttle before engaging the clutch and accelerating. This eliminated the "stumble" for me at stop lights. Technique, only.

Jul 23, 2023 | 10:01 AM

sleighcrane

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From: Parksville B.C.

That's encouraging thought I was actually doing the throttle blip as well trying to overcome it. Simply turning off the EITMS seems to be the trick. With the 475 cam and the lumpy idle lope I don't think I picked up that it was active.Seems fine now

Jul 27, 2023 | 01:57 PM

GPHDXLC

Grand HDF Member

Joined: Jun 2007

Posts: 4,599

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From: Lansing mi

Quote:

Originally Posted by sleighcrane

I didn't catch, what kind of tuner do you have??

Jul 27, 2023 | 02:57 PM

downzero

Stellar HDF Member

Joined: Mar 2008

Posts: 2,328

Likes: 2,205

Quote:

Originally Posted by DeeRoe

That sounds like it's lean to me. If you blip the throttle you're going to get a little bit of "pump shot" fuel to prevent it from going lean when you first crack the throttle. I'm willing to bet if you enrichen it a smidge right where the stumble is, it'll go away without your "technique."

Auto tune is hard in this area because many of these softwares aren't going to want to "learn" when another fuel map is adding fuel, in your case the pump shot or acceleration enrichment.