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Discussion Starter · #1 ·
I purchased a 2006 Sportsman 500 EFI from a guy today. I got a good deal if I can get it to run right. When I contacted the guy he told me it didn't run right, it stumbled. He even made a video but his video didn't actually show it stumbling.

He told me the previous plug was white, he putzes with it and it runs good, then it doesn't. It starts, it idles, and it runs at high speed, but between it doesn't even want to keep going without fiddling. He brought it over for me to look at it. I drove it a couple of blocks, and it was a struggle the whole time to keep it running. Only when the throttle was opened up did it "clear up" and zoom away.

My instinct says it is running lean. I know to check the fuel flow to confirm it has good gas flow. I am new to EFI, so other than knowing it has fuel being supplied, I don't have the process to proceed. Is there a stickit for the problem-solving steps, and better yet, specific to the horrible stumbling I am getting?

I will be so appreciative of any help that will get me in the right direction and I will go from there.
Thanks,
Lew

ps: it is purple??? Supposedly the green camo turns purple?
 

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2008 800 ho efi, 2019 850 SP premium
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Font Line Window Pattern Automotive exterior
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Ball Automotive lighting Vehicle registration plate Font Gas
 

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2008 800 ho efi, 2019 850 SP premium
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You need to get a fuel pressure tester and check the fuel pressure in the fuel rail. You can borrow them at any auto parts store for a security deposit. Sounds like the fuel pump is going out. Its mounted in the fuel tank.
 
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Discussion Starter · #4 ·
You need to get a fuel pressure tester and check the fuel pressure in the fuel rail. You can borrow them at any auto parts store for a security deposit. Sounds like the fuel pump is going out. It is mounted in the fuel tank.
Thanks so much....I suspected a fuel flow issue. I thought I could do it like a carbureted system and simply disconnect the fuel line after the filter but before the EFI and measure the fuel flow, which I think is 25l/hour or something like that.

I don't have the service manual so I don't know where the port is. I did find a 2012 service manual which kind of glosses over the procedure. The fuel rail is supposed to be by the spark plug and for 2012, something like 35psi pressure.

Are there instructions about how to get to the rail and do the testing other than the rather oblique information in the 2012 manual?

I don't know what happened, but the seller gave me a second fuel tank and said the dealer replaced the tank. It appears to have a fuel pump in it. He might have gotten the fuel tank from the guy he bought it from, dunno. I do know that the seller is less mechanically proficient than I am and didn't know how to troubleshoot other than throwing parts at it.

Really appreciate your help!
 

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2008 800 ho efi, 2019 850 SP premium
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Fuel pressure is more important than flow on EFI systems
 
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Is there a sticky, video, or anything on how to locate and do the procedure? I have been searching for two hours and nada :(
Send Forum member latebird a private message including your email address, year, make and model, of your ATV, and he will send you a service manual if he has one
 
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Discussion Starter · #8 ·
Send Forum member latebird a private message including your email address, year, make and model, of your ATV, and he will send you a service manual if he has one
I noticed the sticky at the opening of this forum topic and contacted the person through there and got no reply, and then I found a 2012 service manual, but am not even sure that is the same engine.

Thanks
 

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Discussion Starter · #9 ·
Send Forum member latebird a private message including your email address, year, make and model, of your ATV, and he will send you a service manual if he has one
Got a manual..still a struggle. Turns out the fuel valve could either be on top of the intake or on the fuel line. Didn't find it yet....pulling gas tank next.

Thanks
 

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Discussion Starter · #10 ·
OK.... I don't have a Schrader valve on my fuel rail or fuel line. There is also another user on this forum that reported the same thing. To add confusion, I found the fuel line at Babbits and it shows the Schrader on the fuel line.


If I take that same part number, 252043, and look it up at Partszilla, it doesn't show the Schrader, and looks like mine.

Other than having a point for testing and relieving pressure, I am guessing mine and some others are also missing the Schrader valve.

I can replace the fuel pump and regulator as they are cheap and I have torn it apart that far. I also have the Wix fuel filter on order as well.

Something interesting....when I bought the ATV, he gave me an old tank. Knowing now that Polaris makes you replace the tank with the pump, I assumed that is what happened. So it seems I have the original tank with a part number that doesn't show up, made in USA. Then I have the installed tank with a slighting different Polaris part number, but made in China and appears to be the current part number. I also noticed that whenever the work was done, they never hooked up that little air tube at the top of the tank.

Thanks
 

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Fuel Pump Pressure - 39 psi ± 3
Yep, the fuel line with schrader valve must have only been a brief thing and is now discontinued.
Here is a video showing a DIY rig by a guy testing a Rhino. The procedure is the same when you have no scharader. You just need a gauge, some fuel line, small hose clamps and a bleeder to bleed the air out of the lines before testing and to bleed fuel pressure off when done.
 

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Discussion Starter · #12 ·
I picked up a Harbor Freight tester today. I am going to test the existing tank and the previous tank and see what I get. I did order a cheap replacement pump which I can install and pray. Thanks!
 

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Discussion Starter · #13 ·
Back again....my new el cheapo pump came in. To be clear, I have two tanks, two fuel pumps. The original I assume, and then the one on it that seems to be failing. I thought I would start by doing the fuel pump on what I assume was the original tank. Pulled out the 4 screws (one missing ground wire would have been on) and tried to get the pump out. No matter how hard I tried, and stood on my head, did contortions, I could not get it out.

The bigger surprise is that someone apparently worked on it previously as you can see in the picture. Based on how they "repaired" it, I decided I will abandon the original tank and move on to the one that was installed when I got the ATV recently.

However, won't I have the same problem getting it out of the tank?

Tire Wheel Hood Automotive tire Vehicle
 

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Discussion Starter · #14 ·

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Discussion Starter · #15 ·
OK... the fuel pump in the second tank, made in China for Polaris, part 2520539 is very different than the earlier version above.

If we are still assuming the pump is bad, what do I do? I was able to remove the second fuel pump, but my parts aren't for it although they are supposed to be, or am I wrong?

I gave you the link to the kit above that I bought, and you have a picture of what was probably the original fuel pumps that was Frankensteined, and I am attaching a picture of the new fuel pump.

Automotive tire Motor vehicle Automotive fuel system Hood Automotive design


At least I could get the second one out, but not easily. Under all that plastic, is it the same pump? Is it the same regulator?

If I could get the first one out of the tank, it would be easier to rebuild and seems to have parts matching my kit.

What do you guys think as I obviously need help.
 
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