[Foreman_450]

Hey guys.
So the other day I was riding a 013 EFI 500, ran great, no problems, killed it for a couple minutes and when I fired it back up it started doing this:
With my hand off the throttle, the engine rpm is bouncing about 400 rpms up and down off idle. Basically: Rev, fall. Rev, fall. Rev fall. Continually

Give the bike a little throttle and she smooths on out, it would seem as if the EFI is trying to keep the bike from idling.

Took the air filter off and with it running I can partially block the air flow with my hand and it WILL idle smoothly.

The flap in the body is fully closing, good gas, unhooked the battery for a while, and just general inspection of the surface points no where.

What do y'all think? What should I check, I know it's gotta be a sensor, just not for sure which one does which.

 

[retro]

Get yourself a copy of the service manual and start checking is the best advice I can give ya. If you download the 2014-2016 500 Foreman manual you'll notice that the file name is wrong. It covers all Foreman 500 models from 2004 thru 2016.

With that said, check for any stored DTCs before you do anything. If I had to start guessing though (thats dumb)? I'd check for an intake air leak and then check the IACV sensor. May as well check the TP/MAP sensor too while in there. You know the drill tho.... start unplugging connectors, clean and reconnect... before ya know it all of the plastics are off it and the manual keeps tellin' ya to replace the PGM/FI ECM hoping you'll fall for that $$$ thieving nonsense... when its rarely the ECM that ever goes wrong on Honda's. Good luck and have fun with it!

 

[Foreman_450]

Turns out it is the IAVC, evidently the IAVC is stripped. The round plastic piston thinga bob no longer screws in or out. $20 off eBay and I'm good to go.

 

[Jeepwm69]

Thanks for reporting back on what the problem was. That will help someone in the future.