Hi, This is the first time on this site.I have 2 2016 500 ho 2 up models that are not wanting to start in cold weather.When it is cold and you turn the key on the fuel pump does not kick on.It happens mostly  from 20 f and below.it is irratating because we like to ice fish and use the the machines but won"t start. I have checked all wire  connections , kill switch and so on.(used to work on Atvs for a living,so not completely lost) but this has me stumped. Any help would be greatly appreciated.

Maybe this help, the software number is written on the ECU so you identify. Also the comment about oil weight, I'm not sure the issue this .......I will find out.


Problem:
On certain Trail Tracker 500 EFI, CFORCE 500 and CFORCE 500 HO models, there may be some difficulty
in cold starting the vehicle. When the start button is pressed the motor will turn over but not start. This issue is
more prevalent as the ambient temperature outside drops. Once the vehicle has started everything works
properly until the next cold start.
Correction:
To remedy the situation, CFMOTO has put in place new programming of the ECU aimed at rectifying these
cold start issues for each model listed in this bulletin that demonstrate this particular problem.
Important Note:
Prior to replacing the ECU in vehicles that have the issues described above, assure yourself that there are
no error codes showing on the diagnostic unit. You can also determine the programme version of the ECU
using the same diagnostic unit while using the function ''Read ECU ID'' and ECU software num. The new
program number for the Trail Tracker (EFI) and the CFORCE 500 is R4070123. The new program number
for the CFORCE 500 HO is 6R10A222. Also, ensure yourself that the correct grade of motor oil is used
while taking into account the outside temperature. Check that the battery is fully charged. You must also be
sure that there are no other mechanical problems that may show similar symptoms.

Valuable info, thanks.

[2015 Z Force 800 53/Trail EPS]

Still...I wonder how a map or program would stop it from starting just because of lower ambient air temps. Now my wife can say "F-that" if it's too cold for her to go outside or for a ride...but a machine?   

Thanks on the advice on the ecu will check them right away.

Still...I wonder how a map or program would stop it from starting just because of lower ambient air temps. Now my wife can say "F-that" if it's too cold for her to go outside or for a ride...but a machine?

Just a guess mind you but I imagine it might just be that the mapping doesn't add enough fuel for temperatures below a certain engineer's anticipated amount and not enough is not enough.

I base the following on previous experience with the VDI fuel and ignition mapper. The thing proved to be extremely fussy and required in many cases including mine, a great deal of minute adjusting and testing to both run properly and to fire up reliably in various conditions of air temperature and motor heat. I have never quite wrapped my head around the excuses that small differences in manufacture tolerances between machines of the same make and model ought to be expected to be the reason such dial-in requirements should be needed in order for the quad to start reliably. This when any stock ECU can be removed and put into any other example of the same model machine and it'll run and start just fine.

I have operated gas engines using much cruder fuel metering, including my King Quad when it had a clogged injector out on a group ride one summer. I parked the quad and loaded it the next morning.
I took the air cleaner off, started it and rode the quad to the trailer and loaded it in by just squirting raw gas down the throttle body using a Sunlight dish detergent bottle I'd cleaned and half filled with gasoline. A squirt was good for about five seconds of operation then it would falter and need another squirt. How's that for crude metering, and it started and ran just fine!)
How you can run a motor like this and yet the ECU run motor alone seems to need fuel metering that's accurate to the molecule in order for it to start, is more than I can quite fathom.
The point is though, give a gas motor a shot of gas and it'll start when cold.

But yes, in the case of the OP's problem I just don't think it was getting enough gas when it's really cold, to light the fire.  Not much to be done about that except maybe chuck some gas down the throttle body throat. Or get newer mapping.

[2015 Z Force 800 53/Trail EPS]

Or..give it a shot of starting fluid... Used to do that to save my starters on carbed machines in the cold. But even those would at least try to start. The OP's won't even hit once...so weird. Well, glad mines in a nice warm shop and..it just doesn't get that cold down here. And if it does..I say "F-that" and it sits for a better day..

Still...I wonder how a map or program would stop it from starting just because of lower ambient air temps. Now my wife can say "F-that" if it's too cold for her to go outside or for a ride...but a machine?

My experience is most of these types of vehicles or let's say anything with a motor will have tendency to display female symptoms from time to time. Or course being mechanically powered we are able to use logic, common sense & reason to resolve the issue 

Some of things I have not had time to monitor(sled season) injector pulse with colder temps for enrichment. Is the engine coolant sensor reading correctly & not out of range. Their are conditions I've been told that change the ignition timing during cold start.

I had a CF 400 early Dec. when the temps fell to just above freezing that would crank endlessly then burst to life...like whats your problem  I had that thing in pieces so I shoot raw fuel into the TB, Volt meter on the primary side of the ignition coil & a fancy peak voltage meter on the crank position sensor. I'm not 100% sure & need to get back to it, appeared the ouput of ECU dropped so the spark became very intermittent.