Missed a ride yesterday because of this. Hate that. Anyway...was sitting at a light for 5 second and suddenly my idle jumps from 1500 to a bit over 3000rpm and FI light turned on.

Checked throttle cable, no problem. Took her apart on the side of the road and couldn't find anything. So limped her home.

Before I remembered the bike has a self diagnosis function, I checked everything. Battery good, swapped my backup EJK, spare O2 eliminator thing, checked for intake leaks, etc, etc...

Then remembered and got error code 32.

From the service manual:

"Subthrottle sensor malfunction, wiring open or short"

That's assuming we have the EU model in Taiwan. I'm 90% sure we do. If not, then it's this:

"Subthrottle valve actuator malfunction, wiring open or short."

When you turn the bike on you can hear the fuel pump pressurizing and that butterfly valve moving as usual. But then the butterfly valve keeps moving and twitching. Almost sounds like an older dot matrix printer warming up. Just twitches a bit.

I tore her down and got a look at it. Seems normal; it moves. I also went through all the electrical checks recommended in the manual for those errors. For the subthrottle actuator, all checked out perfect. All wire continuity good and voltage and resistance correct.

For the subthrottle sensor, all wire continuous and voltage resistance good except one. One wire should have had some voltage but didn't show anything.(coming from ECU). Mayne I was doing it wrong. Possible. But if that was correct, the manual recommended a new ECU.

After I put her back together, it seemed to run normally. No FI light and RPM's normal. Drove for about 20 min and decided to open her up. FI light on and power disappeared. I'm guessing "limp home mode" kicked in. So turned off and restarted a few times and she ran completely normal...perhaps better than normal. FI light still on though.

Any suggestions before I take her to the dealership? From some research I'm guessing the subthrottle sensor is screwed up and giving a wrong reading (hence the RPM's jumping up?) Or...really hope not...the ECU is messed up.

Oh, and when the RPM's jump up (usually a few seconds after turning the engine on) they jump to the exact number every time. Very repeatable, so definitely a computer issue.

Thanks

 

I know a guy with a KLX. I'm going to see if I can put his ECU into mine and see what happens. At least can eliminate that

 

Is the metal lobe on the subthrottle doing a quick spin either way when the bike ignition is switched on? I had the take the shaft out & re-align it with the servo after taking off the subthrottle butterfly as my F1 light kept coming on! Was very annoying & took a lot of time to diagnose. No problems with F1 lights now for 2 years.

 

You're talking about the little circle thing inside, right? (Thing that controls the airflow)

It moves back and forth once like usual. Then kinda slightly moves a tiny bit a few times over the next 10 seconds...not like usual.

Of course this happens a month after my warranty ended. Dealer said they'd try to help me out if I take it to them.

 

Oh yeah, the lobe. The one you can see when you pull the black cover off the side of the unit. That moves, yeah.

 

Just got the bike back from the dealer. Took him a week to figure it out. (A one-man show)

My wife was translating, and a lot of terminology was over her head so I'm not entirely sure what the issue was. Mayne someone with more knowledge on EFI could see if this makes sense...

The root cause of the problem was apparently the throttle body was dirty...or throttle sensor. He said it was dirty and after cleaning it, all was well. From what I understand, if the throttle body is dirty, then the sensor will get a wrong reading and strange things will happen?

He thinks what caused it being dirty was the EJK. Maybe I've been running it too rich? (Spark plug always looked good, but that's not a foolproof method, so...)

He said when he got into the ECU he noticed some settings were off. But had no clue why.

In short, he didn't really seem to 100% understand what actually caused the problem. Just that he cleaned the throttle body/or sensor and all was well. Doesn't really give me a confident feeling riding the bike.

Does any of that make sense to anyone?

Main thing...the bike is running and only cost me a week and $67. Decent ending I suppose.