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MidlifeCrisisGuy

Warning: "C1" winter starting issue.

18 posts in this topic

It appears that the C1 ECU parameter, commonly used to improve starting performance, exhibits very high temperature dependency.  A C1 setting that works well in summer temperatures doesn't work at all in near freezing and colder conditions.   

 

I have observed on 2 FI WR450Fs that setting C1 to 8 will make the bike extremely rich during the start cycle at temperatures below freezing.   If the bike stalls in warm up with C1 set to 8 at these temperatures, it is nearly impossible to restart the bike, due to an extremely rich mixture.   Setting C1 to 0 allows the bike to be restarted easily, but that may be the ONLY way to get it to start.  Restart attempts at these temperatures with C1 set to 8 will only result in severe flooding and no restart.

 

This behavior was observed on these bikes with 3 different maps loaded into the comp ECU - stock (all zeros), FMF and the YZ exhaust map.  These bikes both had aftermarket exhaust systems and otherwise ran great.  They had TPS readings (d:01) of 12 and air pressure readings (d:03) of 87 kPA at 3500-4000 feet when local weather stations were reporting atmospheric pressure readings of ~ 100 kPA.  No codes were present on either bike.

 

I recommend that people fully test the ability to start and restart their bikes in cold weather conditions if they have C1 set to something other than 0.  Specifically, in freezing conditions and colder, if you kill the bike during warm up, can it be restarted and can it be restarted when hot.

 

I make this recommendation in order to prevent someone from being unable to restart their bike should it stall out on the trail in cold weather.

 

I hope this helps someone.  I spent 3 days chasing this issue before I isolated it to the C1 parameter.  Luckily mine failed to restart in the garage and not on the trail, in the middle of no where.

 

 

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Isn't it more likely an air density/moisture content issue, rather than tempreture?

High moisture during extreme cold will render the FI extremerly rich....and it can't compensate until you get it running........

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I'm not sure on this one. I have my CO bumped to 15 and at 7000ft on a 36-42 degree mornings with the coldstart knob pulled out it fires up just fine. Also there was a good chance that it was a bit colder than that when we first started. But the interesting thing is the colder it is the higher the air density is. And once your motor is fired up it gets warm pretty quick and that would help with the restarting as well. Have you looked at your air intake temperature sensor? Also the coolant temperature sensor? Does the temp signal make to the ECU? Its there a code if the temp sensor is bad? Kinda strange

Edited by vlxjim

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Mine starts just fine with CO at 10; it's cold (25 F); I live at 7000ft, and I follow all recommendations given   :rolleyes:.

 

 

:smirk:

Edited by AtomicXRer
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They will start fine initially.  Both these bikes started on second kick.   The problem is if you stall it during warm up.

 

Try this:  cold start the bike.  Let it idle 10-15 seconds.  Stall it by blipping the throttle too early or letting the clutch out in gear.  Try restarting it.  You'll experience a severe rich mixture.

 

Double check that the air temp is in fact below freezing by reading the air temp sensor on the bike.

 

We observed the exact same behavior (no restart and flooding) on 2 bikes.  Its repeatable too.

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I'm not sure on this one. I have my CO bumped to 15 and at 7000ft on a 36-42 degree mornings with the coldstart knob pulled out it fires up just fine. Also there was a good chance that it was a bit colder than that when we first started. But the interesting thing is the colder it is the higher the air density is. And once your motor is fired up it gets warm pretty quick and that would help with the restarting as well. Have you looked at your air intake temperature sensor? Also the coolant temperature sensor? Does the temp signal make to the ECU? Its there a code if the temp sensor is bad? Kinda strange

 

 

36 to 42F isn't below freezing.  And the issue isn't with the initial start.   Its if it stalls and you need to restart it.  It then floods continuously.

 

The air and coolant temp sensors worked fine on these bikes.  They read correctly on the FI tool.  No codes were present either.   The only way to get both bikes going after the stall was to reset C1 to 0.  Then they restarted fine.

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36 to 42F isn't below freezing.  And the issue isn't with the initial start.   Its if it stalls and you need to restart it.  It then floods continuously.

 

 

The air and coolant temp sensors worked fine on these bikes.  They read correctly on the FI tool.  No codes were present either.   The only way to get both bikes going after the stall was to reset C1 to 0.  Then they restarted fine.

 

Thanks I know 32f is freezing. But I did say that: "Also there was a good chance that it was a bit colder than that when we first started" And it was. It could of still been 22f - 28f out when I first started out. The sun was still behind the mountains. 

 

Anyway:

 

Air density decreases with altitude. Less air molecules are available Making it rich.  (at 7000ft you would lose about 30% of your power (HP) if was tuned right)

 

As altitude increases you would add less fuel.  Or the opposite.

 

 

 

Air density increases with cold air. More air molecules are available, Making it lean. (So it should be lean not rich)

 

As temperatures decrease you would add more fuel.  Or the opposite.

 

 

 

The more water in the air (grains of water) the less air molecules are available.

 

The more grains of water you would add less fuel.

 

 

These bikes run with an wide A/F from about 12.6 to 16.3 or so. Hence all the tunability with maps.

 

So its still strange that some of us have had no problems with this. And I'm sure all of us have stalled out in warm up. 

 

Do you think that you have a weak spark? Seeing a spark does not mean a strong spark is there. This is something that need looking into more. Don't forget about those guys with the 2012+ that are running the belts on the rear and the skis on the front. In fact if I remember right the one guys was not starting right and the dealer bumped up the CO and all was good after that. There should be some post about it on here somewhere. And the fact that lots of us have had the CO bumped up sense 2012. And now a problem shows up on more than one.

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Last weekend we had our first cold weather ride and my WR and my friend's WR (both 2012s with the competition ECU) were extremely hard to start at the trail head.

 

It froze overnight the night before the ride.  He had his bike parked in my garage, which is un insulated.   He started his bike in the garage no problem.  I started mine in the garage, no problem.   We loaded them in the truck and drove to the trail head, about an hour away.  The temps were sub freezing most of the way there.  28-30F.  The temp readout on my truck said 33F when we arrived at the trailhead, elevation 45-5000 feet.

 

We unloaded.  My bike started on the 3rd kick, no problem.  It usually starts on the second kick on a summer morning, so an extra kick seems reasonable given how cold it was out.   I let it idle for a bit.  At some point I blipped the throttle and it died.  After that, no amount of kicking or cursing would get it to run.

 

I had the same problem last year and spent about a month trying to figure it out. http://www.thumpertalk.com/topic/1112854-warning-c1-winter-starting-issue/

 

Luckily I had my Yamaha FI programmer tool along.  I reprogrammed C1 from 8 to 0.   Still no amount of kicking would get it to start.  Finally we towed it.  It took about 50 feet of turning over before it fired up.  It ran and started perfectly the rest of the day.   We had an excellent ride.

 

While I was trying to get my bike going, my friend was trying to get his started.  No amount of cranking would get it to fire.   I reprogrammed his bike's C1 from 0 to 8.   Finally it started.  It ran fine all day, but it still doesn't start very well when hot.   I think it hot starts better with C1 set to 8 rather than 0, but it still doesn't start without some cranking.

 

Once we got them going we had a great ride.   The sun came out and it warmed up.  We rode about 25 miles of really nice singletrack on a beautiful fall day.

 

When I was troubleshooting this problem last year, I found the plug to be severely wet with fuel.  Any idea on why my bike starts fine but dies when you blip the throttle the first time and then continuously floods ?

 

Any idea how to get my friend's bike starting better in the cold ?   What is the biggest C1 setting anyone has run ?

 

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Why is stalling a cold motor on purpose a problem?

 

I didn't stall it on purpose.  I blipped the throttle.  It quit on its own.   I was asking people to stall theirs to see if they could repeat my no restart condition.

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Last week it was -5 C. My bike stalled while warming up. It fired back up no problem. My C0 is set to -3.

 

Edit: altitute is ~ 500 ft and it was snowing out.

Edited by Spiritwalker2222
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Last week it was -5 C. My bike stalled while warming up. It fired back up no problem. My C0 is set to -3.

 

Edit: altitute is ~ 500 ft and it was snowing out.

 

Why was C1 set to -3 ?  Is that where it runs best (in summer) ?  Did it stall on its own or did you blip the throttle ?

Edited by MidlifeCrisisGuy

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I had the same issue this weekend but luckily I was on a hill as it fires right up with a bump start

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Tim just curious, but did you try to pull the gray knob on the side of the throttle body (left side)?

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Try going the other way. I have been playing with mine quite a bit and have found it starts better with a negative setting, mine is at a -12 right now. I suspect it has  quite a bit to do with the map you are running as well. the CO setting only addresses the throttle at 0, when you hit the throttle it is going to use whatever setting you are at 1/8 throttle and so on.

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Why was C1 set to -3 ?  Is that where it runs best (in summer) ?  Did it stall on its own or did you blip the throttle ?

 

That's where it ran "best" (still has starting issues when engine is hot) in the summer. The bike stalled on it's own, I was 10 feet away from the bike.

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It's not uncommon for fuel injected engines to flood when shut down during cold start enrichment. Did you try restarting with the throttle open and are you running a fine wire type spark plug?

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