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Cold starting

grizztracks said:
Your statement is a little misleading. The update relay that I've referenced many times is a sealed relay unlike the stock relays. It won't cure all the start issues but may reduce the chance of a no start due to a relay freeze up which can happen in extreme cold conditions. The cold start issue is more than likely due to a poor ECU design and programing. My 15 Viper has more of an issue with a warm start than it does cold. It can take several attempts after I shut it down then try to restart after 20-30 mins (haven't done the more recent 16 flash yet).

The rear battery location is not the problem although maintaining a good battery voltage is important for the Cat electronics to function properly. The Viper's extra length in wires to the rear battery has minimal voltage drop in comparison to a Nytro. There is a 15 Viper out there running around with a Nytro engine and electronics that does not suffer from the typical Viper start issues and it's battery is still in the rear with the same size and length of wiring. The Hybrid Viper starts every time as if it was still in the FX chassis.
Click to expand...

( The cold starting issue is more than likely due to a poor ECU design and programming.) I believe this is exactly the issue. Yamaha can reprogram this ECU forever but they can only program it to work within its capabilities. These engines are fantastic engines in my opinion and are the best in the snowmobile industry but need to be controlled with an ECU with a broader range of speed and capacity. It seems as though the original equipment electronics on the Nytros was able to meet these needs. I just can't see Yamaha stepping up and changing the Vipers over due to cost alone. Too bad as these are a great machines otherwise.
 

My new 18’ has been giving me grief lately. 2 tries every time. I have it in the shed right now and the heat has been on all night so I’ll try and fire it up later today...see how it starts in the heat since I’ve never tried yet.
 
Mine fired up this morning after being out over night at below -22 C. Started 2nd try and was a bit rough for a couple of seconds but not really an issue. My friend with a Skidoo says the relay issue plagues them too. They just pull the relay and hold it in their hand for 30 seconds and then it starts after reinstall. Where exactly is ours and how easy is it to access? Might be the same Chinese supplier.
 
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Just fired it up, took 2 attempts. Held it for like 7-8 seconds first try...nothing. No spitting or sputtering, just consistent cranking. Turned sled off, fired instantly 2nd time. +15 degrees in the shed.
 
I have been testing a voltage adjuster to ECU that avoid voltage drops when cranking. A guy help me with the eloctronic. Put it in on the power supply to ECU.

Have been testing since last spring and its works great. -25 Celsius no problem. Waiting for som cold mornings below -30 Celsius to do some cold start testing.

 
Janne339 said:
I have been testing a voltage adjuster to ECU that avoid voltage drops when cranking. A guy help me with the eloctronic. Put it in on the power supply to ECU.

Have been testing since last spring and its works great. -25 Celsius no problem. Waiting for som cold mornings below -30 Celsius to do some cold start testing.

Click to expand...
Nice looking sled, love the venting. I to put an auxiliary power source on the ECU power feed and had the same satisfying results. I removed the device as to preserve my warranty.
Cold starting with bad fuel, old fuel or fuel with an ethanol mix, combined with a voltage drop to the ECU while cranking the starter can be very frustrating. With out a doubt starting a snowmobile in cold weather should not be a "roll of the dice". It should be a given, that when you turn the key your sled will turn over and begin to warm up. I have had the fuel issues. The first ride of this season, the first morning was -12 f and two Vipers would not start but three Apexes did. The Vipers needed to have the batteries jumped after dying while cranking. The Apexes started on the second try but the cranking never slowed as the Vipers did. All the sleds were housed in the same place, summer treatment was identical with the same fuel from the same station 8 months previous. The battery voltage levels were at spec on all the sleds. After running the fuel thru the Vipers and filling 4 or 5 times over the next two days with ethanol free fuel the Viper starting issues seemed manageable. They would start after two or three tries, ridicules however at least they started. It seems the Vipers "slow crank" when trying to start while cold. I know that there are Vipers out there that don't seem to have issues and even a hybrid Viper/Nytro (Nyper) with an ECU from a Nytro without any issues.
I don't have an ECU from a Nytro and my ECU input voltage does drop to a dangerously low level while the starter cranks, maybe too low. In fact the voltage to the entire fuse block drops. I do know that with or without decent fuel and auxiliary power supply wired to the ECU and fuse block my Viper started perfect every time, freezing cold or warmed up. I would love to have a parts list of what your friend installed on your sled.
 
Mine hasn't been bad, started at -20* f both times I've tried on the second attempt , first attempt was a good 10 second crank with a pop or two). I'm going to replace the main power lead and ground with some high quality welding lead wire this summer and see how that goes, not sure what size the factory leads are but the 6 gauge welding wire I have looks far more beefy (more copper than some 4 gauge audio wire I have)
 
The welding cable will have a higher strand count which will ease the voltage drop some but the cable to replace that may help more may be the supply to the ECU and fuse block.


Sent from my iPhone using Tapatalk
 
mine starts hard cold or hot, battery is fine. put in the cr10ek plugs hopefully that helps. very very frustrating. if somebody can come up with a plug and play harness to put a Vector/Nytro ECU in these they are going to make a fortune $$$$$ I get scared to turn this off in the middle of the woods for fear ill be walking. It blows no codes so as far as I know its just because of ECU tuning. Does the EVO flash help? I know they do mostly turbo related ECU stuff but maybe they have something for a stocker. It seems that it is extremely rich when starting smells of raw unburned fuel
 
Flashing the ECU is a software program that makes changes in engine mapping or how the ECU processes information. Like I've said before, no matter how good the programing is it will always be limited by the system or hardware it is controlling. If the System or in this case the ECU is flawed then no programing updates can fix it. A flash update even by EVO can't fix the problems that the Viper's have. The bottom line is that these Arctic Cat ECU's struggle to process information if the input voltage drops to low. Several people have proven that if you maintain a proper ECU voltage during a start cycle the problem appears to be resolved.
 
Mike P said:
Nice looking sled, love the venting. I to put an auxiliary power source on the ECU power feed and had the same satisfying results. I removed the device as to preserve my warranty.
Cold starting with bad fuel, old fuel or fuel with an ethanol mix, combined with a voltage drop to the ECU while cranking the starter can be very frustrating. With out a doubt starting a snowmobile in cold weather should not be a "roll of the dice". It should be a given, that when you turn the key your sled will turn over and begin to warm up. I have had the fuel issues. The first ride of this season, the first morning was -12 f and two Vipers would not start but three Apexes did. The Vipers needed to have the batteries jumped after dying while cranking. The Apexes started on the second try but the cranking never slowed as the Vipers did. All the sleds were housed in the same place, summer treatment was identical with the same fuel from the same station 8 months previous. The battery voltage levels were at spec on all the sleds. After running the fuel thru the Vipers and filling 4 or 5 times over the next two days with ethanol free fuel the Viper starting issues seemed manageable. They would start after two or three tries, ridicules however at least they started. It seems the Vipers "slow crank" when trying to start while cold. I know that there are Vipers out there that don't seem to have issues and even a hybrid Viper/Nytro (Nyper) with an ECU from a Nytro without any issues.
I don't have an ECU from a Nytro and my ECU input voltage does drop to a dangerously low level while the starter cranks, maybe too low. In fact the voltage to the entire fuse block drops. I do know that with or without decent fuel and auxiliary power supply wired to the ECU and fuse block my Viper started perfect every time, freezing cold or warmed up. I would love to have a parts list of what your friend installed on your sled.
Click to expand...

I don't now what what parts he use. I only cut wire and plug it in :) Here some pics but in swedish

downloadfile-6~2.png
downloadfile-1.png
 
grizztracks said:
Your statement is a little misleading. The update relay that I've referenced many times is a sealed relay unlike the stock relays. It won't cure all the start issues but may reduce the chance of a no start due to a relay freeze up which can happen in extreme cold conditions....
Click to expand...

I apologize. I should have worded it, "in my case, the upgraded relays did not help." Warming up the relays, even the improved ones, did not help.

Sundays morning -26f all night. I didn't even try. Placed a heat gun, on low up the exhaust pipe, and went to breakfast at the motel. After, coolant was at -13f. Knew it still wasn't enough.
Heat gun on high for about 10 minutes raised temperatures to -9f.

Sled started, on third try, but very labored. Let idle for a minute. Tried giving it a little rev and it died. About 5 more cranks and started again. Let idle until coolant reach 190f. Good for the rest of the day as usual. No problems at trail stops or lunch. Always 1st or 2nd crank.

I'm tempted to try an inline ATV coolant heater. The Voltage drop theory is intriguing. Hate to starting cutting harnesses and find out the issue is temperature related.

-8f and above appears to start acceptable.
It's the -14f, and colder, morning starts that are a real issue with mine.
 
I have just arrived from a trip of three days. -25 ° C at startup after a very cold night. It started the first time! I just really press very little on the accelerator by starting. I was really surprised by its start so fast the first attempt, however it is necessary to wait until the engine temperature rises to about 30 ° C before releasing it, otherwise it stops. Finding: He is too rich at cold temperature and he needs help to keep idle. Finally, I used the same method as my friend with his Apex and his old vector, except that the Apex did not start ... as usual
This technique has worked twice so far for me, I'm looking forward to the next -30°C.
 
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