Axys 6850 rpm, won't rev past

TreeThrasher · Feb 24, 2017

So part way through the day today my axys started only turning 6850...turns it at all elevations...any throttle position. Sled fires up, idles, takes throttle real well. Basically runs perfect up to 6850 or so then she is done...

Any ideas? I went through all the connections I could find, I adjusted the throttle position sensor both directions a bit...managed to make it idle badly, that was about it.

It surely acts like a soft rev limiter or something similar.

No codes ever thrown on the dash. I rode it for about 3 hours after it started and it never changed.

Thanks!

ak · Feb 24, 2017

Sounds like your power valve are not opening could need cleaned are the relay might be bad.

TRS · Feb 24, 2017

ak said:
Sounds like your power valve are not opening could need cleaned are the relay might be bad.

^^^^^

Jason183 · Feb 24, 2017

I had the same thing happen to my sks last year tps sensior went bad at end of the year.

TreeThrasher · Feb 24, 2017

Ok so my power valve actuator does work...it moves the valves but maybe not full open? Seems strange...
Valves have been out and were cleaned 150 miles ago or so.

What is the story with the relay? Both my relays on the cross tube by the pipe have di electric grease and appear to have good connection

Thanks guys!

ak · Feb 24, 2017

Any codes are engine mods?

06redrevx · Feb 24, 2017

May be a broken primary spring, worth checking

TreeThrasher · Feb 24, 2017

ak said:
Any codes are engine mods?

No codes. Yep it's an Indy Dan long rod bottom end with an 860 top end that we did. Been real good, fast.

It was a light switch, sled was rocking for the first couple hours, then crossed a creek and nailed it and she would turn 6800 or 6850. Elevation made no difference, road vs powder vs hill. No change. 6850 is it

pinko · Feb 24, 2017

TreeThrasher said:
No codes. Yep it's an Indy Dan long rod bottom end with an 860 top end that we did. Been real good, fast.

It was a light switch, sled was rocking for the first couple hours, then crossed a creek and nailed it and she would turn 6800 or 6850. Elevation made no difference, road vs powder vs hill. No change. 6850 is it

Crossed a creek then it started acting up? My guess would be water in a connection somewhere

Sage Crusher · Feb 25, 2017

TreeThrasher said:
Ok so my power valve actuator does work...it moves the valves but maybe not full open? Seems strange...
Valves have been out and were cleaned 150 miles ago or so.

What is the story with the relay? Both my relays on the cross tube by the pipe have di electric grease and appear to have good connection

Thanks guys!

How are checking the actuator? Need to verify that it is fulling pulling the power valves to the full travel- your rpm is about right where they start functioning.

dude · Feb 25, 2017

When you start these sleds the EV actuator at the end of the cable will run thru a full open and full close procedure... you've gotta be quick to look after you start the sled (watch it from the can side of the sled with panel off) I was told if that initial run in and out by the acuator does not go well the check engine light should come on and give an EV code error. You can manually take the actuator arm thru the full open and full close too. Doing it manually while its not running can give you an idea of where full open and full close is to make sure the sled matches those parameters when it does it's self test when started. Not sure if that helps... By the way, one of the two relays on the crossbar above the Y pipe is the EV relay, and the other one is the oil pump relay. I don't think there is a way to tell which is which but that's where the EV relay is...

jhurkot · Feb 25, 2017

Is it a 16 or 17? my 17 had some problems with exhaust valve relay and check engine light came on. No code was shown but there is a way to pull the code when it's active. If you shut the sled off you can't get it back, so make sure if it does come on you pull it right away.

TreeThrasher · Feb 25, 2017

Thanks guys!

So as per the usual way bad things go, I'm down here in McCall for 3 days...yesterday when it dropped to 6800 was day 1...

So I ran into Mile High Powersports this morning to see if they could help me out. Real nice guys, they got me in a hooked the sled up to digital wrench. It had an exhaust valve position learning code. We changed the relays, changed the digital to analog converter and ran the exhaust valve learning function on digital wrench. It threw the same code, exhaust valve position learning failure or something of the sort...so according to the Polaris diagnostic chart, the servo motor has failed.

Interesting part of the deal is, while it was hooked up to digital wrench and doing to learning function, the valve actuator moved through the correct range and sequence, so the failure must be with the feedback side of the servo? Or potentially, and with how my luck is going, likely a failure with the feedback side of the wire harness? We shall see I suppose...they ordered me a servo motor, but I won't have it till end of next week.

Long story short, the garbage electronics on this over priced pile of garbage just caused me to ride my back up skidoo for a couple days...makes me wonder why I bothered to give them 14 grand

Has anyone else had a servo motor failure? Or something that caused the ecu to effectively lose track of the exhaust valve position and put the sled in limp mode? All with no engine light thrown?

TreeThrasher · Feb 25, 2017

Interesting side note for anyone interested. When the sled will only turn 6800 to 7200 rpm, it's not solely due to exhaust valve position. I pinned the valves open and ran it, turned the same rpm. So once the ecu loses track of exhaust valve position, all you get is that much rpm. Period.

TreeThrasher · Mar 4, 2017

Well I got my new exhaust valve actuator...no change. We have a hard rev limiter at right around 7000 rpm...

Does anyone have any insight here? I'm at a loss

ak · Mar 4, 2017

https://www.snowest.com/forum/showthread.php?t=407659

TreeThrasher · Mar 4, 2017

So I read that thread. Seems like his issue and my issue differ in that mine sounds like it is an actual rpm rev limiter.

But maybe similar cause? In that the ecu is not happy with some input? What a disaster. This thing is currently a 15k dollar paperweight.

TreeThrasher · Mar 4, 2017

Does anyone know what inputs into the ecu could make it not rev? For instance, if the tps voltage is wrong, will the ecu put it in a protection mode?

It's in a protect me mode somehow..

Red Mtn · Mar 5, 2017

How do your primary clutch rollers look? My sled did an abrupt loss of rpm a couple of weeks ago too. 6900 was all it would pull... I rebuilt the clutch and replaced the spring. Yesterday it was back up to 7800-7900, still not quite where it should be but rideable until I can track down that last 2-300 rpm.

damx · Mar 5, 2017

My buddy's 17 with 1600 miles was doing this, low rpm and had a bad bog. after we replaced the reeds it helped a bit, pulled the injectors and cleaned them, and sled pulled 8300-8400 all day yesterday. Look a the reeds and change or clean injectors might help you guys out.

Axys 6850 rpm, won't rev past

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