Possible HOT start issue fix.

[excallibur101]

See this discussed in length here,

http://www.ty4stroke.com/threads/hot-start-issue-found.129304/

 

[excallibur101]

Theres a very good possible cause to the heat issue,hot air directed to engine bay,makes a lot of sense after I read the article about the flow of hot air.Maybe try redirecting the air flow so the hot air exits a vent out of the sled instead of through engine bay.the problem is definately heat related.Closing in on the gap for sure.

 

[jetpilot785]

By cooling the radiator it will gradually drop coolant temperature as is dissipates through system.There is no coolant circulating correct so there is still hot coolant through engine but the fan does help to relief the heat starting at the radiator cooler air absorbing the hot,sometimes just turning engine over will help circulate the water.Keep in mind make sure your water/Antifreeze mix are with par .do not add mostly water as it will crack the block if it freezes.the balqnce of mix must be right.A hydrameteter works best.

That may be partially true but how long would you have to run the fan and beat on the battery before it transfers enough to cool the block? The battery would be dead before you got the block cool enough to make the sensors read normal temps. I just think people are just coming up with rituals and dances to get the thing to start. Both of ours have an occasional hot start issue but I think it has more to do with luck whether it starts or not than anything else. The only thing I noticed with ours is if the fan kicks on when you key it up, I wait until it stops pushing the hot air towards the air box and 9 out of 10 times it starts. If it doesn't start immediately, I just keep cranking it over until it fires and that is usually with another couple of seconds. Some people use the kill switch to shut it down, some use the key. Some say theirs never has a starting issue, some do. Some say cool the radiator first, some say to just key it up and rotate the engine without letting the fuel pump prime, some say this, some say that. I guess it comes down to whatever variables are present and whatever method you find starts the damn thing up for you. There isn't enough consistency of the issue and resolutions to know exactly why and how.

 

[excallibur101]

That may be partially true but how long would you have to run the fan and beat on the battery before it transfers enough to cool the block? The battery would be dead before you got the block cool enough to make the sensors read normal temps. I just think people are just coming up with rituals and dances to get the thing to start. Both of ours have an occasional hot start issue but I think it has more to do with luck whether it starts or not than anything else. The only thing I noticed with ours is if the fan kicks on when you key it up, I wait until it stops pushing the hot air towards the air box and 9 out of 10 times it starts. If it doesn't start immediately, I just keep cranking it over until it fires and that is usually with another couple of seconds. Some people use the kill switch to shut it down, some use the key. Some say theirs never has a starting issue, some do. Some say cool the radiator first, some say to just key it up and rotate the engine without letting the fuel pump prime, some say this, some say that. I guess it comes down to whatever variables are present and whatever method you find starts the damn thing up for you. There isn't enough consistency of the issue and resolutions to know exactly why and how.

By rotating the engine your transferring the cooled coolant from the radiator through the engine possibly allowing signal from temp sensor to tell ECM to enable.I am no expert here,only giving you some insight through my experience with my sled and found it was all heat related and these are some of the procedures I have endured to correct the issue,as most of my experience is involved with working on trucks as that is my field of expertise where all basic fundamentals are applied to the same for both.

 

[excallibur101]

By rotating the engine your transferring the cooled coolant from the radiator through the engine possibly allowing signal from temp sensor to tell ECM to enable.I am no expert here,only giving you some insight through my experience with my sled and found it was all heat related and these are some of the procedures I have endured to correct the issue,as most of my experience is involved with working on trucks as that is my field of expertise where all basic fundamentals are applied to the same for both.

As far as how long to leave fan on depends.Usually let fan run for few minutes prior to starting,permitting you have a good battery,generally most fans kick on automatically accord to temperature signal from sensor to the ECM.If at all possible hook up a toggle switch and do it manually prior to starting the machine during its heat soaking cycle.

 

[excallibur101]

Another sure win method is throw some snow on the radiator to cool the radiator quicker.Give it a shot,but not with a AK47. LOL

 

[jetpilot785]

By rotating the engine your transferring the cooled coolant from the radiator through the engine possibly allowing signal from temp sensor to tell ECM to enable.I am no expert here,only giving you some insight through my experience with my sled and found it was all heat related and these are some of the procedures I have endured to correct the issue,as most of my experience is involved with working on trucks as that is my field of expertise where all basic fundamentals are applied to the same for both.

I understand that as the waterpump is driven off the crank. Here is what I'm saying. You are telling me that you run the fan to cool the coolant in the radiator and that eventually transfers up the pipeline to the block which cools the block. Then you are trying to back this theory by saying that by cranking the engine it is pumping the cooler fluids into the block which cools it down which would be a true statement except in order to pump enough fluid to cool the block down to 160-170 degrees which is optimal operating temps, it would take several minutes of continues cranking which would beat the snot out of the starter and battery over time. I have seen several of these vipers including owning 2 myself and even when it is being a little difficult to start, it never cranks more than a few seconds past what would be considered normal cranking under normal conditions. So the engine is staring long before the pumping of coolant has any affect on overall engine temps. I'm just simply saying there is no one certain thing people can put their finger on to aliviate the issue. We are all experiencing things with our vipers and we all have our own methods to get it running again. But in the end, whatever works is the important part and as long as it starts up and gets your #*$&@ home, that's all that matters. I don't worry about it not starting ever, it just takes a couple extra seconds of cranking to get it to fire sometimes is all. Mine both usually Fire first piston up most times bith once in a while it stumbles a couple of times before it takes and it sounds like it may be flooding itself slightly and I would agree it is heat related so no argument there. I now have the Ulmer K&N setup with the power commander on mine and and hers is still stock and I mounted the air temp sensor up and away from the radiator fan so we will see if that helps at all.

 

[Studroes144]

My viper can be sitting all night at below 0 temps and when I go to start it if I let the fuel pump cycle completely then try to start it it'll sputter a bit then start. If I don't let the fuel pump cycle and start it right up it fires right away..that is when it's completely cold and not running for along time, same exact thing happens when it's hot, hot or cold it makes no difference on mine.

 

[excallibur101]

The steps I a have described to you may not totally eleviate your issue as the heat transfer cycle does take its time to pass through,these are steps I have done to my machine that have worked with mine and I no longer have the temp light issue and engine failing to start due to those facts.it has helped.Alternating your airflow through your radiator will also help by exhausting the warm air out of engine area.i must mention occasionally if I am riding on marginal hard packed snow i have encountered the sled running higher than normal temps and a few instances i shut sled down not thinking to cool it down in some deeper snows prior to shutting it off.As i go to restart sled not thinking the temps are still up there the sled would not fire up,sometimes it would if I opened throttle up it would so i knew then to let it cool down a little longer{smoke a cigarrete, take a leak or whatever}it always fired back up without issue.if i was antsy to get going faster i would throw snow on radiator or engine to speed up process{very few occasions}.the ECM is programmed to shut down in extreme conditions such as high temps and low oil pressures most of which is applied to vehicles as well .

 

[excallibur101]

My viper can be sitting all night at below 0 temps and when I go to start it if I let the fuel pump cycle completely then try to start it it'll sputter a bit then start. If I don't let the fuel pump cycle and start it right up it fires right away..that is when it's completely cold and not running for along time, same exact thing happens when it's hot, hot or cold it makes no difference on mine.

normally fuel injected machines.cars,trucks etc. you are not to touch throttle during initial start up as it may flood engine.certain circumstance that rule may differ.

 

[Studroes144]

I don't touch the gas at all on mine, I simply don't let the fuel pump cycle, I turn the key and start it right up and it takes right off. Every time I let the fuel pump cycle and then start it it'll crank a few extra times and sputter some before it starts, but mine has always started, hot or cold

 

[excallibur101]

Your smart enough to do that most people think its like a carburetor with a accelerator pump and choke and end up flooding engine,and there are those those that are just dummies.

 

[Studroes144]

For my sled personally I've seen zero signs where it's anything other than improper fuel mapping on the start. What works for some will not work for others tho as it seems to be a common trend with the viper.

 

[cannondale27]

Hopefully a month from now this will all be a thing of the past and everyone will just be able to turn the key and go.

 

[RTX]

Hopefully a month from now this will all be a thing of the past and everyone will just be able to turn the key and go.

I like the "hopefully"part.
Lol