My take on some Axys rpm/poer loss.

rx1tonofun · Dec 11, 2017

Just got back from a quick test ride. It will be going to the shop tomorrow! New tps and still does the same thing, full throttle low rpm back off and it runs up to 8300-8400 rpm. I tightened up the primary clutch and tried running a few different scenarios. I tried with/without det sensor installed in the head. I tried with/without slp resistor. I also tried a different relay for the power valve system. It pretty much ruined last season for me and has left a bad taste in my mouth for Polaris. I had a '14 pro that worked! I could have bought a '14 or '15 pro for substantially less than what I paid for this Axys and had twice the sled. I'd like to sell but I cant sell it, knowing it doesn't work. I'm hoping the dealer can fix it. I'm done with Polaris!

shortstuff · Dec 11, 2017

So I took mine to dealer last week they replaced all relays, did exhaust valve relearn, adjusted tps and throttle cable, they said i had a few exhaust valve codes but that was it. Took it up riding this weekend at 6000ft I normally ride 8000ft and up. Still only pulls 8000rpm on flat ground or I can go pull the steepest hill I can find at 10000ft and it will b 8000rpm. But now when I back off from full throttle it doesn't gain any more. Talk about frustrating!

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rx1tonofun · Dec 11, 2017

It's very frustrating!

Murph · Dec 11, 2017

rx1tonofun said:
full throttle low rpm back off and it runs up to 8300-8400 rpm.

How far are you backing off?

Have you tried limiting WOT on the throttle body itself? There is enough material there to drill and tap a set screw to limit the throttle valves opening.

rx1tonofun · Dec 11, 2017

I back off about a fifth or so. I checked that the blades were horizontal and they don't go past. I'm bummed it's coming to this, I just want it fixed!

rx1tonofun · Dec 11, 2017

How much do you limit the throttle valves from opening?

rx1tonofun · Dec 11, 2017

Murph. What if the intake boot is holding the throttle body at such an angle that when the plates are horizontal in the body they are actually blocking off the air flow to the reed blocks slightly? When you back off, the top of the throttle plate is elevated slightly and it's a straighter shot into the reeds. I've ridden other Axys sleds that kind of do the same thing, wot they drop off and then backing off they pick up rpm. Mine did it stock but was exaggerated when I started stage tuning it.

Murph · Dec 11, 2017

I’m not sure how far to reduce. My suggestion was only due to the fact that if you back off you get back to 8300 rpm. Only trying to get you back to full revs.

I believe the ECU does a parameter check when the engine is at 100% throttle. Maybe there is a sensor that is sending a signal that the ECU doesn’t like and it’s pulling timing or maybe at 100% throttle it’s going rich on the fuel table.

Is there an exhaust note change when you back off from 100% throttle to where you are picking rpm back up to 83-8400?

rx1tonofun · Dec 11, 2017

It sounds rich at wide open and leans out nicely when you back out of it. It's a noticeable difference and sound too.

rx1tonofun · Dec 11, 2017

I even tried to slack the throttle cable enough to limit the opening but I could never get it right. It's really touchy.

rx1tonofun · Dec 12, 2017

Found out that at full throttle that the tps values jump all over at wot when its running. Back off the throttle and it all levels out and revs up to 8500 rpm! This is with a new tps too. So! Either there's a loose pin fitting somewhere at the ecm or tps connector, or the tps is another bad one, or supply voltage drops enough to show the throttle is at a different position. At least now I feel pretty confident in which direction to go.

Murph · Dec 12, 2017

Good Find!!!

Loose pins have been known to happen, BUT....

What has been more common is a bad ground somewhere. Either the 5V input voltage or the return signal (both share the ground in the TPS sensor)

With the sled NOT running, are you seeing voltage fluctuations when holding throttle wide-open? Especially if you push back on the throttle pin--trying to de-activate the TSS switch.

rx1tonofun · Dec 12, 2017

All fluctuation is with the sled running and supplying its own power. With the machine off and a 12v supply its consistent. I'm sure the machine voltage fluctuates slightly and there's vibration that could contribute to the problem too. I'll check the stator, regulator and tps circuit later to figure something out.

rx1tonofun · Dec 12, 2017

I've also messed with the TSS while watching TPS voltage without a change. The TSS system works consistently.

Murph · Dec 12, 2017

rx1tonofun said:
All fluctuation is with the sled running and supplying its own power. With the machine off and a 12v supply its consistent. I'm sure the machine voltage fluctuates slightly and there's vibration that could contribute to the problem too. I'll check the stator, regulator and tps circuit later to figure something out.

We back fed 12V into a 2012 with a bad stator to limp it out of the backcountry. I wonder if you stabilize the voltage with a battery if you could eliminate your issue.

The stator is now 3 legs DC 14VDC, 14VDC, 16.5VDC.

Another culprit could be one of the multiple capacitors.

rx1tonofun · Dec 12, 2017

I was thinking about that too, a consistent 12v source. I'd rather fix it and know for sure what's going on, so others can get there sleds to work right too.

Murph · Dec 12, 2017

rx1tonofun said:
I was thinking about that too, a consistent 12v source. I'd rather fix it and know for sure what's going on, so others can get there sleds to work right too.

Understood and agree.

If you supply 12v with a battery and the symptom persists— it points toward a bad ground.

How do your grounds look? There is a big bundle of grounds up by the bumper mount. Are they secured and corrosion free?

rx1tonofun · Dec 12, 2017

Initially it all looks good but I'll be checking everything out.

rx1tonofun · Dec 12, 2017

Just checked my stator. It's out of spec for the 16VDC system power coil. Should only be 0.72ohm and it's at 1.2-1.4ohm reading. The other coils test fine. That's the coil that feeds the ECU/sensor circuits..the TPS!

rx1tonofun · Dec 13, 2017

rx1tonofun said:
Just checked my stator. It's out of spec for the 16VDC system power coil. Should only be 0.72ohm and it's at 1.2-1.4ohm reading. The other coils test fine. That's the coil that feeds the ECU/sensor circuits..the TPS!

Nope! It's fine, my meter was messing me up.

My take on some Axys rpm/poer loss.

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