Yamaha Spark 115i - EFI issue? Keeps stalling in idle, won't start

[onlycw]

It began yesterday, when this kick-start only model coughed and then died. A few kicks later, it ran and a kilometer later, the engine stalled again at a red light. Back home, it stalled at the gate. This time, it wouldn't start at all.

Dirt in the injection nozzle? EFI electronics? Am stumped. And not at all mechanically minded.

Fuel consumption appears to be way too high as well.

Often, issues are model-specific. Hope someone will be out there who experienced the same issues?

Cheers!

[papa al]

you did have bike blessed by monk when new, right?

or

maybe a yamaha thing

my nouvo did same after using 4.2 liters from tank.

okay after adding fresh fuel.

[not E20, E80 nor diesel]

if not, mechanic should √ & blow job to: injector, tank, valve, line(s) & filter

√ spark plug & lead

still no va?

chip

on the odd chance you are in Pattaya,

papa can recommend cracker-jack mechanic.

[daveAustin]

Wrong fuel?

[Rama]

idle may need to be reset. Had a bike that did this before. Mechanic fine tuned the idle. Fixed it.

[In the jungle]

My advice is to check the simple stuff first before looking at more complex and expensive things.

Firstly check in this order, spark plug, air filter, battery condition, fuel filter and, if it has done more than about 20,000 km, valve clearances. Problems with one or more of these components can cause the stalling and difficult starting you describe.

A light tan colour is normal spark plug. A black spark plug indicates running rich = too much fuel.

If those items all check out good then my next suspects would be the lambda sensor or the engine temperature sensor. The reason I suggest looking at these two components is because you say fuel consumption is way too high which suggests the bike is running rich. If a lambda sensor fails most engine computers default to running rich in the absence of data from the sensor. The engine temp sensor is, in these simple bikes, used as the equivalent of a cold start device. Cold start device = old school choke = throw more fuel into the engine. In the absence of data from the temp sensor the engine computer most likely defaults to a rich setting. Another reason for looking at the engine temp sensor and lambda sensor is because these can be diagnosed using a multimeter (a common electrical test tool).

Beyond that would be throttle position sensor, engine computer and other stuff.

For now I would not attempt to mechanically alter the idle. You can bet it was right out of the factory and in messing with it you would most likely be seeking to compensate for a problem elsewhere. Fiddling with it would require re-calibrating the throttle position sensor and I hazard a guess that most mechanics don't know this.

It could be numerous other things but the key is to have someone work through the steps logically without a bias towards selling you expensive bits such as engine computers and sensors.

[onlycw]

Thanks - am deeply grateful for the excellent advice!

Found the cause, there was oil in the fuel, clogging the injector nozzle. Fresh fuel diluted it further and this stopped the symptoms.

[papa al]

Wrong fuel?

Bingo!

[papa al]

Thanks - am deeply grateful for the excellent advice!

Found the cause, there was oil in the fuel, clogging the injector nozzle. Fresh fuel diluted it further and this stopped the symptoms.

Curios.

How was oil in the fuel clogging the injectors diagnosed?

Somebody in the family have a chain-saw or sumfin?

[01322521959]

Sorry you atr having prpbs. I have the carb model and always fill up with Shell VPN 95.

"Sparky' loves it.

[MAZ3]

Slightly off subject,but is Benzine ok with the EFI model(2014)?.

[papa al]

Benzine fine but will increase power, watch-out.

[MAZ3]

With my weight,I'll need Dope to get to move me!

[MAZ3]

Benzine fine but will increase power, watch-out.

The wife will cope ;-)