Polaris ATV Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Hello.

I'm pretty frustrated with this issue so I thought i'd try posting here. My local Polaris dealer was no help.

Here's a quick overview of the issue:
My machine has 700 miles on it. A while back it started bogging down when I let off the gas. It will sputter and now it's backfiring, sounds like a gun going off. My first indication of an issue was a melting rubber smell, when I looked the exhaust was glowing red. The exhaust will glow after about 3/4 of a mile at 25 mph. Once it warms up, when I let off the gas it will bog down and backfire. This machine only has 700 easy miles on it (mostly blacktop actually). It's never had ethanol or fuel older than a couple months in it.

What's been done so far:
- tried a different spark plug, first plug had chalky white substance on the tip, same issues with the new plug.
- checked for vacuum leaks by spraying carb cleaner around the intake gaskets. no change in rpm.
- air filter seems fine, clean.
- drained fuel, verified tank was clean, refilled with ethanol free premium gas.
- I tried cleaning the map sensor, but it looked really clean. ordered a new one because i'm really frustrated and they're cheap even though it doesn't sound like the issue.
- Replaced the fuel pump with an ebay aftermarket pump. it definitely ran better w/ the ebay pump, but exhaust was still glowing red. and still bogged down occasionally and sputtered a lot when I let off the gas.
- Brought in to Polaris they ran 4 miles and didn't notice an issue. said the exhaust wasn't glowing for them (I call BS, it happens every single time). They said it's fine.
- Called a 2nd Polaris dealer. They said the problem was most certainly the ebay fuel pump and happily sold me a $470 OEM pump. This fuel pump runs exactly like the original pump (bad). It bogs down, back fires, and dies once it's warmed up. It will start up again after a few seconds.

I think that's about it. I'm debating bringing it in to the dealer I bought it from but they're the folks that sold me the oem pump. So i'm not sure what to do.

Any suggestions would be incredibly appreciated!!!!

thanks you!!
 

·
Moderator
Joined
·
8,736 Posts
What is your idle speed when warm?
Showing any error codes?
I think I'd first check if the TPS is loose or appears to have moved and either check it yourself or try to find someone who knows how to recalibrate the TPS/throttle body voltage settings.
Sounds to me like either a throttle body/Tps miscalibration or the ECM needs flashed or both.
From what I'm finding, Polaris totally changed the style/type throttle body configuration on the 570 machines... Sportsman/Ranger/RZR starting along about 2015-2016+. I'd say that's where the problem lies and the reason some have a too lean problem and some don't.
Using the part number for the newer version TB like you have to do an ebay search shows dozens of them used for sale from relatively new machines and for very cheap. In my experience, this sorta tell tells me its a problem part that's being replaced frequently rather than being adjusted or recalibrated. :nixweiss:
Now this is all just speculation on my part, but if it were my machine or in my shop with the issue you describe that's where I'd start tinkering. With everything else you've tried without any change I'd probably even just fall back on the old "tune by ear" method of TPS adjustment to see if I could get any change if I couldn't find the specs for calibration. Sounds like you've spent a bundle with the dealer's trial and error and haven't gained much so far.
Did anyone you've paid so far hook it up and use the Polaris Digital Wrench software to try to diagnose the problem?
Keep us updated on what you find.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
Polman - thank you for the response. The TPS wasn't on my radar. Did some research and it doesn't seem too hard to at least check. I'll definitely look into it. thank you!

As far as I know it hasn't been plugged into Polaris Digital Wrench. No error codes / check engine light or anything. I probably should bring it in but i'm kind of determined to figure it out on my own at this point.

the Ranger is at my cabin and i'm now back at home so i can't check the idle speed until this weekend. It seems to idle fine though (the dealer said it sounded great). No surging or sputtering at idle. idle speed seems to have always been very consistent.

One other thing i should call out is that it does have problems starting too. It will start for a second and die a couple times before it stays running. Off and on I've had problems getting this thing started since day one. Last winter was really bad. I was told that i had "summer gas" in it and that gas is less flammable than "winter gas" and that Polaris machines are finicky about gas. who knows...but once i put fresh gas in it started better. That was in November/December and the gas was from around August.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #4
I cannot find the throttle position sensor. Is that the same as the pedal position sensor? The shop manual says the pedal position sensor operates as a throttle position sensor. I can't seem to find a way to test the pedal position sensor??

unless i come up with any more things to try i'm going to end up bringing it back to the dealer (a different dealer). I really want to avoid that so if you all have any other ideas or things to try please let me know.

thanks much!
 

·
Moderator
Joined
·
8,736 Posts
I cannot find the throttle position sensor. Is that the same as the pedal position sensor? The shop manual says the pedal position sensor operates as a throttle position sensor. I can't seem to find a way to test the pedal position sensor??

unless i come up with any more things to try i'm going to end up bringing it back to the dealer (a different dealer). I really want to avoid that so if you all have any other ideas or things to try please let me know.

thanks much!
Ah Ha! I've never actually worked on that aspect of the newer Ranger/RZR machines and was wondering about that weird looking throttle body and you just answered my questions. The newer machines are using an electronic throttle pedal to perform the same function as the older TPS setup on the throttle body butterfly. Does your service manual have any information about setting base voltage or calibration?
I just answered my own question about the manual. I was looking at the RZR 900 service manual which uses the same throttle body and pedal. If you read through from the ETC (section 4) I think that's your problem. You've either got an air leak, a faulty electronic pedal or the calibration is wrong.
Power Sports Nation has good used pedals for $85 if you wanted to try a different one and will refund you if it don't work. But if you have info on calibration I'd probably try that first or see if you can find a tech with Digital Wrench and knows how to use it.
Good luck and let us know what you find out.

https://www.ebay.com/itm/Polaris-Ranger-900-XP-EPS-18-Gas-Throttle-Pedal-4014989-21755/362783778282?epid=1578228158&hash=item54779925ea:g:Z~QAAOSw~MZdqKAL
 

·
Premium Member
Joined
·
7,405 Posts
He said no codes per the dealers digital wrench, :fragez::dunno:.
 

·
Premium Member
Joined
·
7,405 Posts
Well first I would test voltage at the battery with the machine running at 3,000rpm.

Then I would put an in line spark tester on the plug and look for a solid strong consistent fire.

Then I would do a fuel rail pressure test.

Then an injector pulse reading.

OP it's tough if the ECM isn't indicating and faults essentially pointing you in the right direction. Other then that its an educated guess or a high percentage seen it before this is the problem type issue.
 
1 - 9 of 9 Posts
Top