viper is running funny

snoprokidf6

snoprokidf6

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Joined
Apr 5, 2007
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521
Age
34
Location
Lee Center, NY
Well, spring break came here at college and when I went home I loaded up my sled to head up north. Got to my drop site, plenty of snow, mid 30's so my sled ran a tad rich, no biggy. I let my sled warm up as usual, playing with the throttle a bit to make sure I didn't foul a plug. After my warm up, i went down the trail, again playing with the throttle to see if it was loaded up from idling and all was fine so I proceeded to WOT and when i let off, it was like the sled went into limp mode. It ran like the TPS was doing what it is supposed to do. I could not move the sled until I let it idle down to normal then take off again. Every time i tried to go again w/o letting the sled idle down, if I compressed the throttle, it was like a rev limiter was set in place, or the TPS was cutting in. This only happens when I let the sled sit for extended periods of time, say a couple weeks to a month, and only then does it for the first 10 - 15 minutes of riding hit or miss. My brother said to get my ECU checked, but I'm clueless on what this could be. My sled has 5100 miles on it and i know it's not supposed to be doing this, i bought it August with 3500 miles on it and it ran flawless for me, never did this before. Any thoughts or suggestions. The engine is complete stock with the exception of the needles dropped one position lower to lean it out a hair and get more power out of it. Again it ran flawless all winter and last december was when I did my adjustments then never touched it again, carbs are also clean but i may clean them again before i take it out on the water this summer.
Any help would be appreciated.
 

I think you mean TORS, not TPS. Have you tried to plug the 2 wires together to see if that helps?
 
First clean the carbs, with todays gas a month is more than long enough for dirty carbs. And unless you running premium octain fuel and your sure of the source i would get those needles back to stock. But not sure by your post. If you droped the needle meaning raised the clip and or washers for sure get back to stock. With a stock viper this is not going to get you any noticable power gain, but i could be wrong. But i do know it will be at a cost. Also check your compression to make sure your not burned down or starting to already. Chris
 
no guys you dont understand. take little assembly out of you sled behind your throttle where the button has to be pushed in. then try and rev up your sled. it retards the motor so it doesnt go above the rpm for engagement.

im thinking it is either a ecu rub through our something wrong with his tors. but idk yet
 
If you bypass the tors and the problem goes away then it is either a bad switch or the throttle cable freeplay needs to be adjusted. I think there is a way to test the switches to see which one it is (throttle or the carb). I thought I saw a thread on that somewhere. How about the coil wires? Have you made sure there are no loose ones? Start at the most likely place and work easiest to hardest to fix and test each problem, one by one, while it's acting up...
 
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Its running too lean when you come down off the throttle. Had the same problem on my Viper at the beginning of the season. At the time, I had my fuel screws set to 2 turns out and had tried to put them back to stock. Every time I would get on the throttle and then let off for a slow corner, sled would act like it was the TORS kicking in but at a slighly lower RPM. Sled would not go anywhere and I would have to let it sit for 5 seconds or so and then would be able to take off again. Turned my screws back to 2 turns, problem solved. Upon further inspection, my v3 reeds are worn out (curled on edges) which may have had something to do with it. Check your pilots, and as stated bring your needles back to stock. May be some crap in the carbs from sitting. Do you use a fuel stablizer?
Just my .02.
--Brian
 
FJviper, it only does it when i first start it up, and i ran it all winter w/o problems, it just started to act up after it sat for a while, i'm thinking it's bad gas, faulty TORS switch, or an ecu rub through, i've heard of a couple of vipers with high mileage having similar problems, not that mine is ready for a top end like most other brands haha, thanks guys
 
yeah, In re-reading your post I see it only does it for 10-15 min. Strange. Did you bypass the TORS like these guys stated? Could be the fuel or electrical but only 10-15 min for electrical? Like you said, maybe just bad gas. Could be some crap in the carbs that needs to flush through? My Viper had about 3500 mi. on it. I know mine wasn't the TORS since I did bypass it. Totally different motor and RPM sound. What are your fuel screws set at?
Keep us posted.
 
not sure, but I can say there is no need to play with the throttle during warm up. it will not load up or foul plugs. I actualy try not to touch mine at all as it will idle a bit higher until you do touch the throttle, then it will idle down
 
I would agree with you viperguy. I don't touch my throttle till I'm ready to move out. Haven't fouled a plug yet. Man....I miss my sled already. Onto the bike I guess.
 
yeah, and I can let it sit and idle for 10-15 minutes issue free. not a sleds for the mid seventies that floods even when you are on the throttle lol!
 
FJViper said:
Its running too lean when you come down off the throttle. Had the same problem on my Viper at the beginning of the season. At the time, I had my fuel screws set to 2 turns out and had tried to put them back to stock. Every time I would get on the throttle and then let off for a slow corner, sled would act like it was the TORS kicking in but at a slighly lower RPM. Sled would not go anywhere and I would have to let it sit for 5 seconds or so and then would be able to take off again. Turned my screws back to 2 turns, problem solved. Upon further inspection, my v3 reeds are worn out (curled on edges) which may have had something to do with it. Check your pilots, and as stated bring your needles back to stock. May be some crap in the carbs from sitting. Do you use a fuel stablizer?
Just my .02.
--Brian
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I'd guess the lowered needles are adding to an already lean condition (cold engine) since it's only happening in the first 10 minutes. I'd start with raising the needles or turning the screws out. You could verify it's a lean condition by flipping the choke when it's hesitating to see if it improves. Based on what's been said about the part throttle lean spot on Vipers, I'd raise the needles anyhow.
 
took the entire sled apart down to bare chassis pretty much, doin my summer over haul, will find out when i get it back together, thanks for the help thus far
 
Same as Viperguy and FJ...
Don't touch the throttle when it's warming up. I've done it by accident before it has warmed up, and then she'll just stall on you.

Full choke to get it started from cold, then half as soon as it's running, leave it there for a few mins, and then no choke and let it idle for a few mins... good to go.
 
akrievins said:
Same as Viperguy and FJ...
Don't touch the throttle when it's warming up. I've done it by accident before it has warmed up, and then she'll just stall on you.

Full choke to get it started from cold, then half as soon as it's running, leave it there for a few mins, and then no choke and let it idle for a few mins... good to go.
Click to expand...
pretty much what I do. I might go to and from half and no choke a few times. always trying to just get it off choke asap as long as it will hold 2krpm. why the full teardown? lots of miles?
 
i bought my 01 sxr this winter an no nothing about it i plan to complete teardown jus so i know what i got an inspect all of it plus my boys walkin now an i wanna gettem started early haha
 
well i took the y pipe off and didn't like the look of the pistons so i took the jugs off (extremely bored) and i have some blow by in my cylinders, so i'm gonna re ring it and change the type of oil i'm using
P1020124.jpg
 
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