2010 Polaris Sportsman 850 Service Manual, Page 60Get this manual
ELECTRONIC FUEL INJECTION Fuel Sender Test
If the fuel gauge reading on the instrument cluster is not working, or if the display reading differs in large comparison to the fuel in the tank, perform resistance test on the fuel senderDisconnect the fuel pumpsending unit connection and measure the resistance between the Purple and Brown wiresIf out of specification, replace the fuel pumptank assemblyPressure Valve
Locate the fuel pressure valve attached to the fuel rail
Fuel Sender Resistance Specifications: Full: Empty: 90 4.5 Fuel Pump Test
NOTE: The fuel pumptank assembly is nonserviceable assembly and must be replaced if determined to be faultyIf fuel delivery problem is suspected, make certain the pump is being activated by the ECU and EFI relay, all electrical connections are properly secured, the 20A EFI fuse is good, and minimum of 7.0 volts is being supplied3Remove the black cap and attach the fuel pressure gauge kit and adaptor to the pressure valveRoute the clear hose into portable gasoline container or the vehicle's fuel tankTurn on the key switch to activate the pump and check the system pressure on the gaugeIf system pressure of 43 psi is observed, turn the key switch "off" and depress the valve button on the tester to relieve the system pressureCAUTION