2012 POLARIS 800 SWITCHBACK ASSSAULT, I CHANGED THE FUEL FILTER AND NOW IT STARTS BUT ONLY RUNS FOR A FE SECONDS AND THEN DIES, I THNK THAT THERE IS AIR IN THE FUEL LINES, RAIL, i APPLIED 12V TO THE FUEL PUMP AND UNHOOKED THE RETURN HOSE AND LET IT RUN FO R A FEW MINUTES, BUT THE SLED STILL WILL NOT STQAY RUNNING?

i gaurantee that it is the fuel pump ressistor up on the passenger side front behind head lamp assembly you will find the connector with two wires going to it. no need to remove old one install new one and connect wires to new one leave old in. dealer only part but not expensive. dont belive dealer when they try to talk you out of it. This is a kit to relocate a ressistor that has been installed in a poor location. I promise this will fix it. My wifes car did the same thing, took 20 minutes to fix and that is only because i am an electrician and am finicky about where to locate wires etc. the kit comes with installation instructions however they are a little vague. trust me. easy fix. my dealer tried to get me to leave car for repair and said it sounds like the theft detterent system. they were wrong and i was right. dont trust em

Sounds to me like the fuel pump is worn out. They DO wear out. And even though they seem to be working, the brushes in the electric fuel pump may not be contacting all the commutator, thus making the pump weak. It may start the motor but can't maintain normal running pressure (27-35psi). Have you run the car out of gas shortly before this problem surfaced? If you have then it's your fuel pump. It was damaged when the tank ran dry. Even though the pump may seem to be working, it's still badly damaged and needs to be replaced.
Just as Matmenzies has stated, get a fuel pressure gauge and test the pressure. I'd start with a complete check of all your vacuum lines. Check for cracks on the vacuum hose that connects to fuel pressure regulator on the fuel rail. Also, if you can, get a hand operated vacuum pump to check the regulator. If you can place a vacuum on the regulator and it holds, I'd say move on the fuel pump and check it.
BTW, if the fuel filter has been changed, you may want to check to see if it was installed backwards! Some fuel filters are valved and will cause symptoms like this. However, this is an immediately noticeable mistake and you haven't provided enough info for me to say more. I'd pull it and check that it has any flow at all. You could have sucked in a big dirt ball and blown it right into the new filter, effectively stopping fuel flow. Then I'd blow out the fuel lines, just to be sure.
Start with these 2 things and post what you find. We'll go from there.

Faulty fuel filter.

Fuel filter installed backwards.

Bent fuel line.

check fuel pressure to the fuel rail to see if you are recieving fuel to the fuel rail if so the injectors are suspect

Try pounding on the gas tank with a rubber mallet or similar tool. (careful not to dent the tank) Try starting it. If it runs, replace the fuel pump (it's nfg). I've diagnosed numerous fuel pumps this way. Remember the pump needs to be replaced, if you drive it, you don't know when it'll fail for good. Hope this helps. Please post the results.

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