My guess is one solenoid is to "pull in" to allow fuel flow & other solenoid is "hold in" to maintain IP fuel flow to injectors OR 1 of the solenoid you're referring to is for "cold start" circuit. Did you check for any blown fuses?? I suggest you acquire/study a JD 5103 tech manual. My knowledge of JD tractors built after '87 when I ceased serving as a JD dealer SM is limited
Top solenoid is the fuel shut of solenoid I and is tied to cold start sensor. This is the common one individuals have an issue with and blowing the fuse. If I could post pictures I could post the fuel system and components to help better show what I知 talking about. Any idea how the numbering systems work for the tech manual? There seems to be a two letters followed by 4 numbers that determine the year models it is for.