I have a 2019 FLSB Sport Glide. The idle speed has jumped to 1500-2000 rpm, will not throttle down. After I got home and the bike sat about 15-20 minutes, I went back out to the garage, and their was a strange sound from the gas tank. I loosen the gas cap and a big vacuum sucked a lot of air into the tank. I re-started the cold motor, and it idled fine while the motor was cool. After warming up, the idle surges up and down between 950-1600, the engine acts like its going to die. Any ideas ? Thanks for your help.

 

Is the bike stock? If not, done anything to it lately?

 

1. Try an idle reset:

To reset your idle setting back turn the ignition switch on for 10 seconds off for 10 seconds (do not start the engine), repeat a total of 4 times. That should reset your original throttle position.

The throttle by wire will remember throttle position each time the bike is shut down

That said, some are having problems rolling the throttle a bit when using the kill switch

This can cause this type of problem


2. Do you have an OEM Gas Cap?

3. Check your fuel tank venting.

 

Hey GalvTex, it's got Stage One SE tune, SE intake, and Tab Exhaust. Has been running fine for months. The vacuum being pulled in the gas tank is new, I've never had the tank off. It's strange that with vacuum on tank vented, it idles fine, but if you twist the throttle a few times it runs like s***, and idle then hunts up and down.

 

Thanks for your advice on TPS reset, did the reset, still acts as first mention. It has stock gas cap, will try to check venting on fuel tank, does the tank need to be removed to check venting. ? Don't know how to check vacuum. The speedo display now shows a Check Engine icon, after running poorly a minute. I'll keep on following ya' all advice. Bob

 

Okay on the TPS reset was a easy free check.

See if there are any codes associated with the check engine light, might be a clue to what is going on.

https://www.fuelmotousa.com/p-29661-...ble-codes.html

You may be able to check the vacuum by looking under the tank and locating the vent tube.

 

Thanks for the links to check TC's. Is that number 7 some kind of valve in the pic ? I checked the gas cap (don't ask how). When you flow air into center of the cap, it is blocked, when you pull air from the center of the cap, it flows freely. So how did the tank pull a vacuum ? It would have to be the gas cap not venting into the tank ? Just thinking. Thanks. Bob

 

Link to parts diagrams:

https://www.harley-davidson.com/us/e...s?aribrand=HDM

Ref:7
62150-85
VALVE,FUEL,X
Price: $19.11

I think it is a one way fuel venting valve to vent in case of excess pressure. You seem to have vacuum so I do not know.

 

It wasn’t releasing pressure and you thought it was in a vacuum?

 

A vacuum as you describe & observed in the fuel tank is not normal from my observations. I suspect the gas cap is not venting under vacuum as needed. 🍻
Btw, is EITMS enabled and also coming into play? 🤔