This thread and another on Cummins Forum at
https://www.cumminsforum.com/threads/fuel-shut-off-solenoid-fss.569868/ have been very helpful to me while troubleshooting the no start issue I've been having. I wanted to add to the conversation in case it might help someone else.
My truck (1996 Gen II 2WD, 358k on the clock) wouldn't start. I found that the boot that covers the plunger assembly had rotted away, apparently long ago. What happend in my case was that the adjustment portion of the plunger assembly had come out of it's socket, so that when I tried to start the engine, the plunger pulled up as usual but the adjustment rod end didn't follow along, keeping the fuel shut off. Initially I thought the issue was the missing boot but a new boot didn't fix the problem. As it turns out, there's a split ring spring that holds the adjustment rod inside the plunger. When the solenoid is assembled, the adjustment rod is pushed insied the plunger against an internal, very stiff, spring. The hole that the adjustment rod fits into has an internal taper followed by an internal groove. Pushing the adjustment rod into place causes the taper to compress the split ring spring until the spring encounters the groove, at which time the spring opens slightly, snapping into the groove and locking the adjustment rod inside the plunger.
Once I discovered this, I tried to get the split spring to snap back into it's groove to no success. I noticed that the split spring was worn on one side, so I carefully pulled the split spring from the adjustment rod & turned it over so the not worn side might engage with the groove and hold the assembly together...no joy.
So, it's off to O'Reilly Auto Parts for a new solenoid (
https://www.oreillyauto.com/shop/b/...utomotive-truck-1996-dodge-ram-2500#addToCart) . I guess with 358k on the odometer I can't complain about another $112 dollars.
I've uploaded photos to show what I'm describing above...I hope it's helpful.