Extreme ATV Enthusiast
Join Date: Mar 2011
Location: Shenandoah Valley,Virginia
Not familiar with kill switch issues.
As I understand it, pump comes on briefly with key on to build initial pressure then shuts off until engine is cranked and efi sees either a certain rpm and/or ANY rpm trigger from a sensor. Then turns back on.
Doesn't explain why it likes ether though.
Crank speed. Is battery up to snuff? If weak it may effect fuel pump and starter crank speed. Checked charge, connections and load tested battery?
Diesel engines sometimes get ether dependent when it is used unnecessarily. We call them ether babies. They wont start without it even when it is not needed.
Any reason to suspect low compression?
Have you checked for diagnostic fault codes?
2007 Sportsman 800
1500 miles, mostly at Hatfield-McCoy trails, WVa.