Originally Posted by lr172
are you reading 9.8V while the solenoid is engaged and the engine is spinning via the starter motor? If so, 9.8V sounds about right. If you disconnected the main batt feed to the starter during this test, measure voltage at the solenoid and the input side of the 30A relay. That might help you narrow down where you are picking up the resistance problem. I would speculate that there is a problem with the winding in the solenoid that is providing incorrect resistance that is drawing too much power as well as not providing the proper magnetic field to move the plunger / contacts.
if you were getting 9.8V with the engine spinning, you're looking for the plunger / contacts hanging up inside the solenoid, due liekely to improper clean up of surfaces during installation if new or pitting contact surfaces if old.
Larry, thanks for the feedback! This is exactly what I did. The solenoid and relay used to be wired with #14 wire but were replaced with #10. the problem still persists to the same extent even know the voltage went up under load by about half a volt after the wire size change.
I think I'll swap out the solenoid today, I heard a Ford Crown Vic solenoid fits