Nytro powderlites DIES WHEN HOT

[Ultralord]

sounds like the trouble I was having.....but i dont have a RB3?? it was running perfect before it got heat soaked. Same kind of riding conditions. Also always stored on lift in a heated shop.

Once I had all the panels off it seemed to come back to life but I didnt do alot of testing as I was mostly concerned of getting out of the deep back country.


shrug....

That Is a bad fealing My buddy says to me hay pull a plug and check her for spark I told him to come take a look I had all the panels off It took him 5 minutes just to find a plug

But the good news was I had my tow rope and did not need it

 

[Hrt Offroad]

If when really hot and riding without a lot of air going through it stop and go to start but won't it has been fuel rail gas boiling and listen to hear if fuel pump is working right.
Not a lot of venting with trail tank guys and they are having some troubles by the phone calls we been getting.
Try snow on fuel pump or look at fuel pressure when it won't start.
Let us know so we can look in this problem.
Dave @ www.powderlites.com

My fuel pressure was anywhere from 0-10 during cranking but wouldn't hold a constant when mine wouldn't start, and the pump didn't sound quite right. Pressure would also spike every once in awhile. It did this twice after a long fast trail ride with lots of air movement, but only hovering around 0 deg air temp. Let it sit for 15-20 mins and it would start like a champ???
The hot fuel thing kinda makes sense...I have been looking into a putting a u cooler in my tail section to enable me to get rid of the radiator and free up some space, air flow and heat under the hood...maybe it's a better idea than I thought!?!?!

 

[WingNutRacing]

fuel boiling!

Never thought of that, you may have just pegged it!!!

Some old dirt bikes did that if I remember right.

When problem occurs:

Engine is very heat soaked
Fuel pump wants to work, but can't build the right pressure, i.e: 48psi, only goes to around 25psi sled will try to fire and spit and sputter, then die again: seemingly a lack of fuel, or the injection system is not working correctly, or lack of spark????
I"ve tried to blow on the return line from the fuel pump to force fuel through the tank into the system, worked once in a while but not really.
At the same time the RB3 box was very hot to the touch.
My initial thought was the fan relay is not working, or the temp sensor in the thermostat housing is faulty, therefore not kicking on the fan,, or the overheat light.

I've unplugged the RB3 box and the fuel pump still acts the same when turning the key to build fuel pressure, just wont start with the box unplugged.

Same issue with the box plugged in, but tries to start and dies again.

Now that you mention the fuel boiling issue, that seems logical, the symptoms are pointing in that direction.

I will go through the cooling system processes today and make sure that everything is working right.

If that fan is not coming on, no cooling back there at all.

Can you wire for fan operation all the time when the engine is running?????
Can you get a different sensor to kick the fan on earlier in the heating process?
Can you install an optional fan to blow downward on the fuel rail?
Can you wrap the fuel rail to protect it from heat?

We need to figure this out, I'm gettin frustrated, but I think we are on the right track now....

Thanks for any help....

 

[skydog]

yes right on!!

This makes tons of sence! When tuning my sled on stand it would slowly start to run lean.(pop and miss down low) When the motor was getting hot (190-199 on gauge) That is when the fuel is starting to boil. So i added fuel with my laptop. But after sled cooled down and restarted it, was SUPER rich down low! So now the hard part is out of the way! (finding the problem) Now for the fix!! What about hooking fan up to run all the time and run the fuel line back around there to get some air on the line??

Skydog

 

[WingNutRacing]

Ah ha!!!!!!!!!!!!!!!!!

Yep, I think we've got it....

Bring on the ideas, lets get this fixed, like I said before, THIS SLED FLAT RIPS when it's running right!

C'mon Powderlites, get us a good fix figured out!!!!!!!!!!!!!
I have regained faith!!!!

Thanks fellas, that's some good trouble shootin right there!

 

[Blue Light]

Great thread guys...I'll be watching.

I had a problem with mine at Cooke City ( 7 - 10 K feet ) this week, different though.

Got new map and fuel regulator set up ( 46# fuel pressure ) and got high A/F numbers even at high altitude and low boost. At WOT numbers would climb too high at even 9 lbs., then I could burp it to about half throttle and go right back to WOT and numbers would be low ( in the 11's ). WTF...any ideas?

BL

 

[Hrt Offroad]

Great thread guys...I'll be watching.

I had a problem with mine at Cooke City ( 7 - 10 K feet ) this week, different though.

Got new map and fuel regulator set up ( 46# fuel pressure ) and got high A/F numbers even at high altitude and low boost. At WOT numbers would climb too high at even 9 lbs., then I could burp it to about half throttle and go right back to WOT and numbers would be low ( in the 11's ). WTF...any ideas?

BL

I would guess that your o2 sensor is pooched!!

 

[WingNutRacing]

sensor

How much leaded race fuel are you runnin?? Those sensors and leaded race fuel don't get along very well....

 

[Blue Light]

91 and maybe 1-2 gal. of AV to clean it up per tank, never more than 12 lbs. The sled runs good and rips, just bad numbers...I'll check it out.

Talked to Dave and he says no more about 1 gal. of AV per tank as it burns slower and doesn't work so good on boosted 4 strokers. He says its cool in boosted 2 smokes though. I don't really get it though, it makes sense that AV is prolly made for higher compression engines.

BL

 

[Tuesday]

At least I am not the only one that has had this issue. When I was first posting about response was pretty dismal.

Had a similar fuel issue on a Yamaha 4x4 quad. They covered it up so much that with a bit of mud and debry it would super heat the fuel. Yami did come out with a tank insulation kit that helped. Also helped to vent some of the contained heat.

Seems like a few have had problems under the similar conditions. Set up snow with very warm temperatures. Most are confident that its not a moisture problem as the belly pans are dry.

Looking back on my 2 days ride the snow was so set up I really should have just run without the hood. I am betting there would have been no issue.

Hope we come up with a permanent solution because there is no way I am paying 16k for a new nytro hehe.

 

[Ultralord]

How much leaded race fuel are you runnin?? Those sensors and leaded race fuel don't get along very well....

I RUN VP C-12 I just replace the o2 once a year I would get about 300 miles on my T apex and then 02 would hang about 13 and not change thats when I would change the o2

 

[sledskiing]

I think my fan is busted. Last season my sled ran flawlessly and the fan would kick on from time to time. I have not heard it once this season and have had similiar issues discussed above. It only happens to me maybe twice a day but it will go away if i cruise around to get air flowing.

 

[Blue Light]

Good info.

BL

 

[Ultralord]

Anybody got any Ideas on where to install a fan maybe just a togle switch

 

[WingNutRacing]

Bad fan relay!!!

Found one big part of the problem, yep,, the fan relay was toast, that means,,,,, no kickin on of the fan, and I can almost guarantee the temp sensor is fried too......

Was thinking of a place to put a small fan also to cool that area a little better, but might try some vents first. Maybe some number plate vents from BR Tech..

Next year the big old headlight is gettin ripped out and replaced with one or two smaller ones and screen kit to cover the hole, maybe a Mtn fit headlight delete screen...

I have also mentioned having the option of turning the stock fan on when you wanted to, and also have it operate like it normally should. I just need someone to figure out that wiring scheme,,,,,, any electrical dudes out there????

 

[sledskiing]

where is the fan temp sensor?

 

[Tuesday]

Found one big part of the problem, yep,, the fan relay was toast, that means,,,,, no kickin on of the fan, and I can almost guarantee the temp sensor is fried too......

Was thinking of a place to put a small fan also to cool that area a little better, but might try some vents first. Maybe some number plate vents from BR Tech..

Next year the big old headlight is gettin ripped out and replaced with one or two smaller ones and screen kit to cover the hole, maybe a Mtn fit headlight delete screen...

I have also mentioned having the option of turning the stock fan on when you wanted to, and also have it operate like it normally should. I just need someone to figure out that wiring scheme,,,,,, any electrical dudes out there????

Where is this relay at? Any pics?

 

[WingNutRacing]

pics

Hey fellas, just got back from my buddies shop, sorry, no pics. I'll definately get ya some soon.

The relays are in front of the motor, under the airbox(stock) or under the intercooler(turbo). There is a sequence of them. The fan one is the first one in line as the wiring harness comes to them.

The temp sensor is in the thermostat housing, that dome shaped unit that all the large coolant hoses come into on the oil tank side in front of the engine. There is an electrical conection on there, that plugs into the temp sensor. That little bugger is tough to check while on the sled, and kinda messy to change, and it is also kinda fragile.

I'll have pics tommorow....

 

[IRONMAN]

I dont have a powderlights turbo but if your problem is under hood heat my sled should be worse being its a front mount. I have removed the headlight, and the rad and installed a rear tunnel cooler and small lites. I havent had or heard of others having the problem you describe, even peeps with mcx's. Mabey someone should try no head light to cool things off for a ride see if that helps. If not it sounds like the rb3 cant take the heat. jmo

 

[spray25]

I have an MPI stage two and have idle and starting issues that seem to be heat related as well. Once the sled has been worked hard and is heat soaked the sled will idle very lean and stall. Restarting it can be difficult but is possible. I have been able to richen the lowend (green setting) enough to make it idle descent, but it is till difficult to start and the off idle and low speed cruise are now pretty rich. If I get on the trail for a while with good cool air rushing through it seems to start much easier. Also as someone else described in the morning when the sled is cold it idles very rich only to be about right once the sled is heat soaked again. After reading this thread I decided to remove my headlight for yesterdays ride as an experiment. I am sorry to say I saw little if any diferrence in it's hard starting. I had tons of air and even snow coming in the headlight hole.

There is still another possibility with heat though. I have MPI's 1-1 regulator and a return fuel line going into my gas tank, but I am still using the OEM fuel pump which means the pump is now working all the time and much harder. I am wondering with the extra work it is doing is the fuel pump over heating and boiling the gas in the line? If it is the venting would likely not help cool the fuel line since it is rubber, fairly short, and largley covered by plastic or hidden behind the motor and radiator.