Yamaha Fiore - Idle Surging

[wantan]

Our Yamaha Fiore 2011 (Fuel Injection) has a "surging idle" occasionally. The idle increases from normal to faster in a frequency round about 0.7-0.9 seconds then. The idle increases so much that the automatic clutch engages and the bike wants to move slightly for a short moment. This happens only occasionally, mostly directly after the engine start. If the engine is switched off and on again the problem most times is gone. I also noticed that the idle ist too fast most times, but sometimes it is OK.

No Warranty because we have no service book. And our local Yamaha service mechanics aren't much interested in such small problems

Someone has heard of such thing and has an idea?

[BSJ]

Generally speaking it's usually the TPI sensor or O₂ sensor that causes the most problems with EFI. Firstly you may need to strip the body off pull all the electrical plugs and clean them, then lube with WD40, put back together and test. If it still does it you may need to get an engine analyser to diagnose which part is at fault.

If your lucky it maybe a loose or disconnected wire.

Edited November 9, 2012 by BSJ

[wantan]

Generally speaking it's usually the TPI sensor or O₂ sensor that causes the most problems with EFI. Firstly you may need to strip the body off pull all the electrical plugs and clean them, then lube with WD40, put back together and test. If it still does it you may need to get an engine analyser to diagnose which part is at fault.

If your lucky it maybe a loose or disconnected wire.

Shit, i will need a whole day to get rid of all this plastic junk for doing a body strip and put everything together again. This is the only thing i really hate on this little modern step through scooters. There are so many hidden screws, plastic lips, ... especially if you are doing it for the first time it takes a lot of time

With "TPI sensor" you mean the Throttle position sensor? I can not find a Throttle position sensor in the parts catalog. I guess its included in the throttle body assy. I would assume a TPS is needed on a FI bike?

This is what i found in the parts catalog to have a look at:

• THROTTLE BODY ASSY 2,116 Baht
  
• MANIFOLD 386 Baht
  
• INJECTOR ASSY 705 Baht
  
• SENSOR, OXYGEN 1,149.53 Baht
  
• THERMO UNIT (Sensor) 135 Baht
  
• FUEL PUMP COMP. 1,864 Baht
  

Did i forget something? It seems the Fiore has basically the same engine and frame than the Filano. Sadly it seems impossible to find a Service Manual.

Edited November 9, 2012 by wantan

[VocalNeal]

Wantan,

How does the bike get ridden? Maybe it just needs a good run or a tankfull of real petrol? Could also be a dose of bad fuel.

[wantan]

Wantan,

How does the bike get ridden? Maybe it just needs a good run or a tankfull of real petrol? Could also be a dose of bad fuel.

My wife rides it, mostly very short rides. 100m - 2km. Sometimes 3km - 5km. But never longer rides. But i don't want to tell her to better "ride it hard", because she doesn't like safety gear very much

The O2-Sensor does not look good. But if the Idle Surging happens and i disconnect the O2-sensor nothing changes.

[VocalNeal]

Have you tried a new plug? Or give it a good canning yourself?

[BSJ]

Wantan,

How does the bike get ridden? Maybe it just needs a good run or a tankfull of real petrol? Could also be a dose of bad fuel.

My wife rides it, mostly very short rides. 100m - 2km. Sometimes 3km - 5km. But never longer rides. But i don't want to tell her to better "ride it hard", because she doesn't like safety gear very much

The O2-Sensor does not look good. But if the Idle Surging happens and i disconnect the O2-sensor nothing changes.

The only way I know if the O2 sensor is trashed is to test it with a multi meter, for resistance, short of having a computer diagnostic.

Shitty petrol can lead to small deposits blocking the injectors....but you said it runs fine most of the time. Ultrasonic cleaning can fix that more often than not. Ultrasonic cleaning can dislodge small deposits very effectively in complex parts.

Don't go buying all those parts until your checked the basic stuff. Wiring, connectors, hoses, air filter, spark plug. Sometimes it some silly thing.

You really need a manual to follow to diagnose whatever it is. There must be a manual in English available somewhere. It will have all the common faults listed, the test procedures.

Edited November 9, 2012 by BSJ

[wantan]

The only way I know if the O2 sensor is trashed is to test it with a multi meter, for resistance, short of having a computer diagnostic.

Shitty petrol can lead to small deposits blocking the injectors....but you said it runs fine most of the time. Ultrasonic cleaning can fix that more often than not. Ultrasonic cleaning can dislodge small deposits very effectively in complex parts.

Don't go buying all those parts until your checked the basic stuff. Wiring, connectors, hoses, air filter, spark plug. Sometimes it some silly thing.

You really need a manual to follow to diagnose whatever it is. There must be a manual in English available somewhere. It will have all the common faults listed, the test procedures.

No, i will not buy all these things. But good to know how much they cost

Yes, the bike is running fine most of the time. I guess the problem is caused by a sensor sending a wrong signal and than the electronic reacts to the wrong signal.

I searched for a service manual but haven't fount one. Neither in english now in thai. The only Yamaha FI scooter manual i found was for Zuma 125cc, in english. But it all seems different, even the error codes (blinking warning lamp).

[BSJ]

Without the manual it maybe in your best interest to get on a Yamaha forum and ask for help.

[VocalNeal]

As far as i can see there are only two external sensors the O2 the the lean angle, others must be in the throttle body. I was interested to note the the injector is direct in the cylinder head and not like Honda in the throttle body?

Bung some fuel injector cleaner in it and see what happens. Or make some of your own. If you are into alchemy and need a project. There are recipes on the interweb. I made some SeaFoam-like liquid just for a laugh.

[wantan]

As far as i can see there are only two external sensors the O2 the the lean angle, others must be in the throttle body. I was interested to note the the injector is direct in the cylinder head and not like Honda in the throttle body?

Bung some fuel injector cleaner in it and see what happens. Or make some of your own. If you are into alchemy and need a project. There are recipes on the interweb. I made some SeaFoam-like liquid just for a laugh.

I already put fuel injection cleaner in it. Problem still there. Yes, fuel injector sits on the cylinder head.

Without the manual it maybe in your best interest to get on a Yamaha forum and ask for help.

Good idea, but i don't know any good Yamaha scooter forum. And the models sold by Yamaha are very different all over the world it seems. Maybe there are some good thai forums. But difficult to describe such problem in thai for me

Guess i will bring the bike to the Yamaha headquarter in Bangkok. They have a decent service center there for problems that cannot be solved by the shops. Its just 20km to the east on the BangnaTrad from where i live. I guess its the best i can do now without wasting more time or starting to replace parts just by guesses.

Thanks.

[VocalNeal]

Not related but many years ago we had an old Dodge Omni. My wife used to complain it would stall at 4-way stops. Every time I took it out to replicate the problem, I never could. I put this down to the fact that when I drove I took off from the house at a "decent" lick, then drove around town to get the engine warmed up etc.

The Fiore may just need a run at a decent throttle opening to blow out some cobwebs.

[wantan]

The Fiore now has been at the service center at Yamaha headquarter on BangnaTrad. They cleaned the throttle body. Thats all. The bike ran fine now the last two weeks after the cleaning. No idle surging occured. If it ever comes back i will report it again here.

I guess some sensor (or contacts of a sensor) at the throttle body was dirty. Thanks all for help

Edited December 7, 2012 by wantan

[BSJ]

That's good news.