Started out the night before the ride when I let it idle it started acting funny but when I rode it hard it acted fine again. So went out today on a nice ride and about 10 miles in I stopped waiting for my bud and it started cutting out at idle. I went a little further and it sputtered and died. Waited around a little and it fired up and drove sputtered backfired died. Had to fire it back up about 5 times on the way back to the truck. At high rpms it would run still missing but it would at least run. Then back at the truck started idling real high above 2k rpms then would sputter out and die. Now that it's home still doing the same thing idles real high when I start it and been sputtering out. Been going through it and can't find anything obvious. Started it this evening and it just idled real high and ran good. Had good throttle response and idle around 2500rpm. No check engine on and never over heated. Has good gas in it ethanol free and plugs are only a few months old. I have only owned carbureted quads before this and am at a loss? where do I start. thanks and sorry for the long post.

 

Look at the "sticky" post in the expert section on 800 efi problems.This applies to all 500,700,800 models. Common complaint on cutting out,erratic idle,backfiring, general bad running,etc. Most of the time it's because of wiring shorts in the t-bap sensor harness,tps or crank sensor harness or even in the connectors themselves.Check the t bap harness coming from the sensor located in the rubber boot at the back of the throttle body. Also check the wiring from the tps sensor on the throttle body and crank sensor harness wiring. Check these areas for obvious bare wires,also for any "soft" wires which could be from internal breakage. At times some machines would run good,then they would start acting up. You can check for codes on the speedo,but they often don't show up or throw codes that aren't correct. Like code 21 "loss of sychronization" If you throw a code 41, 45 or 46 then this could be close to the problem of a t-bap wiring problem. Very few times is the sensor themselves at fault,mainly just the thin efi sensor wiring and connectors.You can also eliminate a fuel pump problem if you have a fuel pressure gauge and adapter to fit the fuel rail. It must hold 39 psi without any drop. If you narrow it down to a harness problem,don't use the Polaris kits! You'll get the same thin wires! Stronger wiring kits are mentioned on the "sticky" post and some are available on Ebay. http://www.otbpowersports.com/t-bap-info.htm Here's the link on the harness kits. OPT

 

Thanks for the info new at this efi four wheeler stuff and sorry for the common newb post. I already tore all the plastics off to get a better look so I'll be out there today trying to chase stuff down.

 

I feel slightly dumb but is there anyway a loose throttle cable could have caused this? I bumped it and throttle went crazy so found where it had loosened up and got it all tightened and adjusted properly and it's running fine. I'm gonna put some of the stuff back together and maybe take it for a little run around the house see what's going on.

 

It's entirely possible if the throttle slack was more or less than the 2 mm (.080) slack called for between the contact points of the etc switch in the throttle housing,especially if the contacts touched. Try it and see how it does after the slack is adjusted.This distance is usually about 1/8" slack on the thumb throttle lever. If it acts up again,then still could be an intermittent wiring harness problem. This is how most would do,run good for awhile,then run crappy.Keep us updated. OPT

 

Thanks and it has run good today so far, ran it for about 20 minutes around my 5 acres. Tomorrow I will take it a little further out see how it does.

 

either a too tight or too loose cable can activate the etc and cause the limiter to kick in so it coupld be the issue. just keep the tbap harness in the back of your mind though.

 

Took it for a cruise today dead again. Was fine till I slowed down and shut it off then when I turned it back on it would run good for a short amount of time then stumble die. So as a test I popped the radiator cap and it was barely luke warm and the block was real hot. So I took off my side plastics to let air flow and turned it on and had no water flow. I let the wind blow through it and let it sit and it would run longer. So I would let it sit and run it till I got it to a point where I could get my truck in and pick it up. Hope the motor ain't toast but took the impeller off and it's been worn down to about nothing so that part should be in Friday and we'll see again then. I feel pretty dumb but didn't get a warning on the display or nothing. Stupid little piece of plastic.

 

Why the impeller melted is because of cavitation,same thing that can happen to pwc impellers. I've even seen these stainless steel impellers almost eaten through along with melted plastic atv impellers! It's the trapped air that circulates through the water pump cavity that heats up and does the damage,melts impellers,damages seals,etc!.You may want to remove the thermostat housing and check that the seal is ok also. When you replace the impeller,make sure you jack up the front end(manual says on its side,but front end works better) Have the tires off the ground about 6-8 inches,fill the radiator and crank the engine with the radiator cap off. You can help it along in removing any trapped air as it warms up by squeezing the hoses. When the fan cycles on,the level will drop in the radiator,then you can add coolant to the radiator. You may have to do this several times to purge all the trapped air. When you're certain the air has been purged,top off the radiator,replace the cap and top off the overflow bottle.Make sure the hot light doesn't come on and the fan cycles on and off. OPT.

 

We burn up brass ones at work but that's on a huge water system the wear looks the same. I still can't believe it's plastic. What did that save 12 dollars maybe. Thanks for the info I always got to do the same thing on cars or pop the highest line open to bleed the air.