Look at the clutches. Broken spring,Too tight belt deflection. Dirty?
SRXSRULE2
Expert
Well the spring has broken before, it has already been changed once or twice, it’s not broken. However I have the sled all apart right now, no belt on it. I Can fire it up, it will some what idle, not at the 1800 or so rpm it usually does when cold, maybe 1500-1550 rpm. If I touch the throttle slightly it will bog and stall (litterally touch it enough to move the throttle blades). I loosened the throttle cable even though it wasn’t tight, same deal. If I let it warm up, it won’t stall but it doesn’t come back to idle without running rough (low idle) for say 3-5 seconds.
Just surprised to see all these posts about tight valves and then I open it up to find everything as it should be. Looks like brand new under the valve cover (it does get maintained well)
Count yourself lucky! Maybe the throttlebodies are out of sync.
There is a diagnostic mode of dash. Hold both bottom buttons left and right sides in. Check the TPS readings. This is just like a car. All the IACV is doing is creating a vacuum leak. Make one and see. Maybe the IACV port has carbon in it? Obviously since you said the valves arent tight you should start a new thread for your issue.
TILAM1
Veteran
- Joined
- Jan 26, 2017
- Messages
- 45
- Location
- Ontario
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- Canada
- Snowmobile
- 2017 SR Viper R-TX-SE
- LOCATION
- Eastern Ontario
I was just thinking throttle body sync too. My motorcycle was having occasional stalling issues and a sync seems to have cured it. Not much talk of syncing the throttle bodies here on this site.
There was a couple flashes ago. Some were found off. I checked mine and they were perfect.
https://ty4stroke.com/threads/synchronizing-the-throttlebodies.145291/
Allan
TY 4 Stroke Junkie
Seam like you have everything going on like I did and my valves were out of spec. Mine would start at normal idle of 1800 the drop down to 1200 and sound like a 2 stroke when cold but when warm it was fine. you say you can out a 0.008 feeler gauge in . the spec is 0.0083 -0.0098 so they are out of spec?
SRXSRULE2
Expert
While they are at the low end of the spec being at 0.008” are they technically “out of spec”? Yes, but I don’t own a set of feeler gauges that measures to the ten-thousandths of an inch and I don’t have any metric ones either. But 3 ten thousandths of an inch? We’re splitting hairs here. If that is causing it to not idle properly that’s a joke. The valves being at the tight end of the spec for 20k km’s.. I’ll take it, that’s normal wear. There are millions of cars on the road using the same direct acting bucket design that don’t have this problem. Yea, these things see more abuse because of the RPM and the load they are under all the time, but the problem lies somewhere else.
SRXSRULE2
Expert
I have been using the diag mode on the gauge, problem being it’s too slow to catch anything. You would need something that can show real time like a scope to see what’s going on with the IACV. The valve does move, I had it off and I can see it cycle when the key is turned on.
Make a new thread.
SRXSRULE2
Expert
As requested, I am starting a new thread on this. Details are as follows. I owned a 09 nytro which started in the cold all the time, even to the amazement of a lot of other nytro owners. I remember seeing people with their sleds in trailers with heaters in them trying to get them to start. I had nothing special done to my nytro, maybe I was lucky. The sled couldn’t do anything else right, but it would start in -40 Celcius. After putting nearly 5000 Km’s on the nytro in a season, enough was enough and I jumped ship. My dad only ever owning Yamaha’s his whole life back to an 81 exciter decided to march on.
This is my fathers sled, a 2014 viper with 19,890 km’s on it. It is stock, has absolutely nothing done to it as far as modifications go except for skis and a Polaris brake handle as apparently cat doesn’t know how to design those either. This sled in my opinion from day 1 never started as it should. It has had two flashes, both of them which didn’t improve the starting in my opinion. 2 seasons ago it back fired so bad it blew the muffler apart, that was a fun trip as they were back ordered (surprise). The end of last season became the new problem where it won’t idle cold and stalls when coming to a stop. Basically in the morning going for a ride, you have to start it, keep on the throttle lightly and ride around in circles in the parking lot so it doesn’t stall. If it does stall, it takes a lot of cranking to get it going.
Things I have done. I checked the IAC to see if it moves, it does move when you cycle the key to Run. I have checked for vacuum leaks, can’t find any. Spark plugs are new, belt is off so there is no resistance on the engine. If I go in my garage and fire it up, it will “hunt” at idle from 1450 to 1600 rpm. It should idle at about 2000 and come down to 1800 IIRC. If I even touch the throttle it will stumble for a second and stall. 3 dealers have said to adjust the valves so I pulled the valve cover off, rotated the crankshaft so the cams were on base circle at the valves I was checking. They are on the low end of spec but in my opinion they are within spec. Can’t remember what compression numbers were, I checked last spring but they were good and even across the board. Leak down, they are less than 5% and they are even on all 3 cylinders. Checked with 2 gauges, same results.
In my opinion, that of a master tech for Ford, it seems like an IAC issue as a car with the same symptoms would act the same. Why you can’t purchase this separate, I’m not sure. My father doesn’t want to blow $1400 to find out that’s not the issue and I don’t blame him. If anyone knows where I could source an IAC separate I’d be glad to go that route. I’m working on hunting down a used one.
This is my fathers sled, a 2014 viper with 19,890 km’s on it. It is stock, has absolutely nothing done to it as far as modifications go except for skis and a Polaris brake handle as apparently cat doesn’t know how to design those either. This sled in my opinion from day 1 never started as it should. It has had two flashes, both of them which didn’t improve the starting in my opinion. 2 seasons ago it back fired so bad it blew the muffler apart, that was a fun trip as they were back ordered (surprise). The end of last season became the new problem where it won’t idle cold and stalls when coming to a stop. Basically in the morning going for a ride, you have to start it, keep on the throttle lightly and ride around in circles in the parking lot so it doesn’t stall. If it does stall, it takes a lot of cranking to get it going.
Things I have done. I checked the IAC to see if it moves, it does move when you cycle the key to Run. I have checked for vacuum leaks, can’t find any. Spark plugs are new, belt is off so there is no resistance on the engine. If I go in my garage and fire it up, it will “hunt” at idle from 1450 to 1600 rpm. It should idle at about 2000 and come down to 1800 IIRC. If I even touch the throttle it will stumble for a second and stall. 3 dealers have said to adjust the valves so I pulled the valve cover off, rotated the crankshaft so the cams were on base circle at the valves I was checking. They are on the low end of spec but in my opinion they are within spec. Can’t remember what compression numbers were, I checked last spring but they were good and even across the board. Leak down, they are less than 5% and they are even on all 3 cylinders. Checked with 2 gauges, same results.
In my opinion, that of a master tech for Ford, it seems like an IAC issue as a car with the same symptoms would act the same. Why you can’t purchase this separate, I’m not sure. My father doesn’t want to blow $1400 to find out that’s not the issue and I don’t blame him. If anyone knows where I could source an IAC separate I’d be glad to go that route. I’m working on hunting down a used one.
If it is IAC then a simple check would be to remove airbox and check that the IACV passageway isnt plugged.
After a stall how do plugs look?
Map sensor also.
SRXSRULE2
Expert
I haven’t pulled the plugs but I know they are going to be wet/ rich as I can tell it’s running rich by the smell of the exhaust and the low idle. Plugs were new last season, I can throw another set in, just didn’t feel the need to foul another new set.
Near the end of last season I swapped the baro and map sensors (same part number) to see if there was a change, ran the same. I used my voltmeter to back probe the readings with the key on engine off, both the baro and map were reading the same as they should. When it’s running, the map sensor changes voltage as it should, also checked it using a vacuum pump.
A couple nights ago I pulled the IAC apart, it was clean and the valve is not binding. When I turn the key on the valve opens up to say 50 % as it should for cold start. When the key is turned off it cycles to the nearly closed position and then slightly open. Interesting part, when I removed the solenoid from the housing part of the IAC and cycled the key a bunch of times, each time the valve would come out a little further (towards the closed position) and would change its rest position key off. I reinstalled the valve and tried it, it idled pretty good around 1750-1800 rpm. Watching the IAC reading on the gauge it was moving around and changing like it should. I let it warm up to operating temp and shut it off. Yesterday I let it sit outside the garage for a few hours, tried it and it stalled. Gauge was showing 120 on the IAC which seems to be the max/ full air bypass.
So without being able to see how this ecu works, I would assume the only inputs to the fuel injection would be the map, baro, intake air temp, coolant temp, crankshaft speed, and throttle position. I have ruled out the map/baro, crankshaft speed is fine. Intake air temp seems to read what my thermostat in the garage reads so I rule that out. Coolant temp reads normally. The throttle position sensor reads 0% and 0.6volts and idle and 98% (can’t remember voltage) at WOT.
If someone can chime in with their TPS readings and IAC values when idling to compare I will have ruled out just about everything.
Near the end of last season I swapped the baro and map sensors (same part number) to see if there was a change, ran the same. I used my voltmeter to back probe the readings with the key on engine off, both the baro and map were reading the same as they should. When it’s running, the map sensor changes voltage as it should, also checked it using a vacuum pump.
A couple nights ago I pulled the IAC apart, it was clean and the valve is not binding. When I turn the key on the valve opens up to say 50 % as it should for cold start. When the key is turned off it cycles to the nearly closed position and then slightly open. Interesting part, when I removed the solenoid from the housing part of the IAC and cycled the key a bunch of times, each time the valve would come out a little further (towards the closed position) and would change its rest position key off. I reinstalled the valve and tried it, it idled pretty good around 1750-1800 rpm. Watching the IAC reading on the gauge it was moving around and changing like it should. I let it warm up to operating temp and shut it off. Yesterday I let it sit outside the garage for a few hours, tried it and it stalled. Gauge was showing 120 on the IAC which seems to be the max/ full air bypass.
So without being able to see how this ecu works, I would assume the only inputs to the fuel injection would be the map, baro, intake air temp, coolant temp, crankshaft speed, and throttle position. I have ruled out the map/baro, crankshaft speed is fine. Intake air temp seems to read what my thermostat in the garage reads so I rule that out. Coolant temp reads normally. The throttle position sensor reads 0% and 0.6volts and idle and 98% (can’t remember voltage) at WOT.
If someone can chime in with their TPS readings and IAC values when idling to compare I will have ruled out just about everything.
