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Discussion Starter · #1 ·
Rode home last evening about 10km over our lake after a great day hacking around in the woods in a couple feet of fresh snow. I was running at an easy crusing speed of 100km/h or so (about 60 mph) according to the speedo, about half throttle and 7000 RPM.

At this speed the throttle is usually very dull; you have to completely pin it to get any response (when you do, though, the sled accelerates strongly up to 140 -- 145km/h). But this time it was worse. It even seemed to bog from time to time. And it cut off briefly going over bumps.

And when I got home, it backfired quite a bit and the can seemed unusually hot. I guess these are symptoms of the fuel map problem which has been reported on this forum.

But get this -- I opened the gas cap, and there was a lot of vacuum in the tank. *%@??!! This can't be right or good. Vacuum in the tank = fuel starvation = lean condition = burndown, right? And/or fuel pump damage, it seems to me.

I'm going to start by look for a kink in tank venting (if I can find it). I assume I can't just loosen the gas cap.

Could this possibly be related to the glowing can problem? What do you guys think? Computer overcompensating for fuel starvation, maybe? Check your tank venting, guys!
 

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Discussion Starter · #3 ·
Well, it sounded like air rushing in. Maybe I'm wrong. I traced the vent lines and there were no kinks. It's a funny kind of system with a "T" joint, one line going through a one-way valve ("out" only) and vented to the frame; the other to some kind of vent.

I rode about 200km today. The sled runs fine, except that it doesn't like to hold 7000RPM or more for more than a couple of minutes.

It must be the notorious fuel map problem. I'm guessing now that EGT's go up at high speed cruise and the computer starts dumping in more and more fuel. The fuel burns in the can, making the computer think the EGT's are even higher, fooling it into thinking it's a lean condition when actually it's too rich. Thus ensues a vicious cycle until the can glows and the computer goes over to limp mode. What do you guys think?

Anybody get flashed to solve this?
 

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you can take the check valves out,i removed them on a few machz's,they keep sticking and cause erratic running,they run just fine removed.
 

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That could be the fuel pickup problem?
Mine did that and it was sucking air and not getting all the gas out of the tank. Even after my dealer claimed to have fixed it I can only suck 8.7 gallons out of the 10.6 gallon tank? Then it starts doing like you are saying and cutting out (running out of gas).
But if I run it out like that its at the 130 miles on the trip meter mark plus I have a jerry can.
 

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Discussion Starter · #6 ·
MXZonly said:
That could be the fuel pickup problem?
Mine did that and it was sucking air and not getting all the gas out of the tank. Even after my dealer claimed to have fixed it I can only suck 8.7 gallons out of the 10.6 gallon tank? Then it starts doing like you are saying and cutting out (running out of gas).
But if I run it out like that its at the 130 miles on the trip meter mark plus I have a jerry can.
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Hmmm, does yours do that only when the tank is low? Because mine does it even with a full tank.
 

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My tank pressurizes when the temps get high - the heat exchanger heats the tank sufficiently that the vapour pressure becomes quite high. Removing the cap will pop it into your hand. If its under suction the cap will be very hard to remove.
 

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Discussion Starter · #8 ·
joevella said:
My tank pressurizes when the temps get high - the heat exchanger heats the tank sufficiently that the vapour pressure becomes quite high. Removing the cap will pop it into your hand. If its under suction the cap will be very hard to remove.
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But shouldn't the tank vent system relieve positive pressure, as well as negative?

But I suppose a little positive pressure wouldn't hurt anything, so maybe that's it, and I just couldn't tell whether it was suction or pressure. Hmmm. So maybe there's nothing wrong; I just have the fuel mapping problem.
 

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709 000 059 is the vented gas cap from an Outlander 400 ATV, thats what I put on mine. The one off the 05 440 is the same except it says "Premix Only 40:1" or whatever on it and I have oil inject on my 800sdi as you would expect. I put it on because my 04 600sdi was really bad for putting right up and making a really annoying buzzing sound when I shut the sled off. The 440s all come with them so that the tank has no chance of pulling a vacum and causing a lean condition.

Not sure if this relates specifically to your hot can complaint but its worth a try for the $20 or so.

Also, I have an 800sdi in my 05 Mod Renegade and the exhaust temps in the mid-range, 6000-7000rpm are rediculous, I see EGTs at sustained temps of 1390-1420 at times. I have 1400 miles on my sled and have no signs of failure or any damage to my engine and aside from buying at Boondocker EFI box to adjust the map there is no way for me to change the mapping and cool it off. I run an MBRP can on mine and I have not seen and discoloration of the stainless and assume the heat there is not an issue like the 04/05/06 600sdi sleds have seen at times. I also have an 04 600sdi the threw blue flame out the can at time and has given me no problems since the remap, didn't have any before either other than the hot can.

Just food for thought, good luck.
 

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Discussion Starter · #11 ·
PrairieRenegade said:
709 000 059 is the vented gas cap from an Outlander 400 ATV, thats what I put on mine. The one off the 05 440 is the same except it says "Premix Only 40:1" or whatever on it and I have oil inject on my 800sdi as you would expect. I put it on because my 04 600sdi was really bad for putting right up and making a really annoying buzzing sound when I shut the sled off. The 440s all come with them so that the tank has no chance of pulling a vacum and causing a lean condition.

Not sure if this relates specifically to your hot can complaint but its worth a try for the $20 or so.

Also, I have an 800sdi in my 05 Mod Renegade and the exhaust temps in the mid-range, 6000-7000rpm are rediculous, I see EGTs at sustained temps of 1390-1420 at times. I have 1400 miles on my sled and have no signs of failure or any damage to my engine and aside from buying at Boondocker EFI box to adjust the map there is no way for me to change the mapping and cool it off. I run an MBRP can on mine and I have not seen and discoloration of the stainless and assume the heat there is not an issue like the 04/05/06 600sdi sleds have seen at times. I also have an 04 600sdi the threw blue flame out the can at time and has given me no problems since the remap, didn't have any before either other than the hot can.

Just food for thought, good luck.
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Thanks a lot guys! I'll try the vented cap, just for peace of mind. And I'll try to get the new fuel map. Take it from there. Sure do love my Summit, but these problems are kind of frustrating.
 
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