Another Cold Hard Start...

RonH

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Stalls it doesn't cause. Maybe I misunderstand the problem you are having. If stalling after start, that is no way a battery problem. The problem I have had, and discussed in detail for several years are mostly go out to start cold, the motorcycle fails to start, sometimes can be started with full throttle, sometimes not. Can be a real bear to ever get running if full throttle unsucessful. What happens is the battery, although not too bad, is just weak enough where the motorcycle does not start and floods, then starting gets iffy from there.
So if stalling ect after start, another story. If hard to get started sometimes cold, get a battery and most likely problem will be gone.
 

SHUMBA

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Dec 29, 2018
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ONTARIO, CANADA
An update. I’m now at 36k miles and experienced another stall; this is the fifth or sixth stall since I’ve owned the bike. Also, the bike is now at the point where I twist the throttle ever so slightly for a quick start; warm very slight but cold significantly more. Still no check engine light or fault code...

Did a deep dive into shop manual, which I used to see if I could find any diagnostic codes, and found reference to poor engine performance and no codes, see picture. Since the bike is requiring some throttle to start I now feel I’m at the point where the problem is consistent enough to troubleshoot.

My plan of action, once I complete a medical procedure next week.

Take bike to dealer and use Yamaha diagnostic tool to determine if any fault codes exist. If so, address.
Next, use diagnostic tool to check throttle position sensors and adjust to midrange value if not already.
Do same for acceleration position sensors.
The manual specifically identifies these sensors along with coils and fuel injectors. Since the bike runs fine the rest of the time and spark plugs look great I really doubt a problem exists with a coil or injector.

Comments? Anyone have experience with these two types of sensors, four in total?
View attachment 65132
Very difficult hard start today.
2018 ES one year since new 22,000 km or about 15,000 miles.
Bike was stored in a semi heated shop, full of 91 octane gas with fuel stabilizer and ran for a good half hour before the bike was put away in mid November.
Started the bike on March 12th, a little hesitant, but no problem.
I've been riding about five times this season without any issues. Bike now at home in my garage.
Now, today, about 8 C or 42 F I tried to start the bike, but it cranked ok, but very weak firing, no gas smell either.
After four attempts, I plugged the battery tender in and let the starter motor cool and looked in my Yammy manual for any help.
As many of you, like us up here in Canada the dealerships are closed. So no answers there. Always 91 octane, bike was almost full of gas.
After about 15 minutes a final attempt at a start was successful. Then went riding for the afternoon along with five starts with no issues.
WTF??
Any comments or suggestions or assistance would be greatly appreciated
SHUMBA

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Nikolajsen

"Keep it simple"
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Pretty sure is was due to a battery with too less cranking power.
Maybe the previus trip was to short to fully charge it.
I would change the battery
 

old1959

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Mar 3, 2018
Messages
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Texas
Clarification on my stalls. The stalls are random; extremely random and lately have been occurring after sitting at a light for a minute or two. When I twist throttle to accelerate, engine stalls.

Regarding hard starts, bike turns over fine and always starts but requires a twist of the throttle. A little when warm and more when cold. All this leads me to question the throttle and accelerator sensors. More to come once I can get the bike to the dealer and tied into their diagnosis tool.
 

Cycledude

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Jan 29, 2016
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Rib lake wi
Clarification on my stalls. The stalls are random; extremely random and lately have been occurring after sitting at a light for a minute or two. When I twist throttle to accelerate, engine stalls.

Regarding hard starts, bike turns over fine and always starts but requires a twist of the throttle. A little when warm and more when cold. All this leads me to question the throttle and accelerator sensors. More to come once I can get the bike to the dealer and tied into their diagnosis tool.
what year is your Tenere, if it’s a 12 or 13 have you had the wiring recall done ?
 

SHUMBA

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Dec 29, 2018
Messages
912
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ONTARIO, CANADA
Clarification on my stalls. The stalls are random; extremely random and lately have been occurring after sitting at a light for a minute or two. When I twist throttle to accelerate, engine stalls.

Regarding hard starts, bike turns over fine and always starts but requires a twist of the throttle. A little when warm and more when cold. All this leads me to question the throttle and accelerator sensors. More to come once I can get the bike to the dealer and tied into their diagnosis tool.
Okay thanks please let me know what your dealership has to say
SHUMBA

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old1959

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Texas
My S10 is a 2017. Replaced plugs approximately 10k miles ago. Stalls have happened throughout ownership of the bike, before and after spark plug change, but so infrequent that I've never been able to troubleshoot or at least feel confident enough that another mechanic could troubleshoot. Now that the starting is requiring a throttle twist I feel that maybe something could be found.

Unfortunately, I'm an older guy so been staying home so haven't been to the dealer yet. Of course, I've been out for a spin or two:cool:
 

WJBertrand

Ventura Highway
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Jun 20, 2015
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Ventura, CA
Wonder if a reflash by Anthony would cure this?
Good question. I know (think?) that Anthony's flash defeats the deceleration fuel cut. This is a function that stops the injectors during deceleration to avoid excess HC emissions, since with the throttle closed there may be too little air and the mixture would otherwise go rich. The ECM switches to an idle map when engine RPM drops to idle speeds. My stalling events usually happen after deceleration when pulling in the clutch at mostly very low speeds or just before stopping. I've wondered if the ECU sometimes lags switching from the fuel cut map to the idle map, just long enough to let the engine stall? I've never had the engine stall once idling however.

Like old1959, these stalls happen so infrequently it'll take several thousand miles and several months for me to be able to see any indication that the re-flash has fixed this issue.
 

old1959

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The latest news. And one that I may have to eat some crow... The past few times that I’ve been out I noticed the bike was becoming hard to start even when warm. Also, I have a voltmeter/USB plug but the voltmeter is hard to read in direct sunlight. However, I ended up in a low light situation and happened to noticed the voltmeter dropping around ten volts while starting Which seem low to me. This got my attention and so when I returned home I started bike in a dark garage so I could easily watch the meter and saw less than ten volts.

Consequently, today I replaced the battery with a 14 Yuasa. Bike starts fine now, or at least in warm weather and when hot. To all who said to replace the battery and I disregarded, my apologies. Haven’t a clue if this will impact the occasional stall; may need to ride a few more years to know since they happen so infrequently.
 

old1959

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Texas
Update. I have ridden over a thousand miles since the battery change. Bike has been starting fine and no throttle needed hot or cold (haven't experience much cold). I'm now wondering if the previous battery was marginal for a long time. Regarding stalls, none but they happened so infrequent I feel to early to tell.
 
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