I have a 92 polaris 500efi that runs fine untill it hits 4000 rpm at which time the rpms kick down to about 3500 then back up to 4K back down to 3500 and so on at WOT. I am unsure of what to check or where to start. Any help would be much apreciated.
I have changed 1 of the 2 fuel filters so far and then blew out the other one. As for the cleaning the carbs this is an efi unit so I was under the impression that it didnt have a carb. Worth looking into though. Thanks for the input.
Check the variable resistor (TPS) on the intake. This componant will give the ECM the exact throttle position with a 0 - 5 volts reference. If the TPS gives out a bad value, the ECM will NOT activate the injectors accordingly to speed and throttle position.
P.S. : TPS can be checked with a voltmeter when engine is running or with Ohmeter when engine is OFF and sensor disconnected.
3 wires are connected to this sensor. 1 for Ground another for 5 volt and the other that sends the info to the ECM. That last one will make the voltmeter go between 0 to 5 volts depending on how much you are opening the throttle (when engine is running)