My new to me '94 Cummins 2500 started doing something cute. You go to start it and it fires up right away but immediately dies. It seems if you stab the throttle at the right time it'll catch and stay running. Once it's running it runs fine, no hesitations, good power, etc. could it be the shut off solenoid? Lift pump?

ballast resistor

Lol, I wish, that's at least something I can relate to, this diesel stuff is pretty foreign to me. It also seems like 3rd times a charm. It usually starts and dies the first two but catches on the 3rd try with the throttle stab trick

does it have the deal where you turn on the key and wait for the start light to go out?

My bet is that the little rubber boot on your fuel shutoff solenoid has deteriorated and is jamming up the movement of the shutoff rod. That solenoid has two coils ... a big "Start" coil that is energized when you hit the starter. Once you release the starter, the solenoid drops to a second smaller "run" coil. With the rod boot jamming up the works, the start coil will yank open the fuel valve but the run coil isn't strong enough to hold it open so the fuel is cut off and the engine dies. That's what happened on my '97 Ram 2500 CTD. Geno's sells just the boot at https://www.genosgarage.com/product/sa-4153/fuel-system-accessories-replacement-parts

Yeah it's got the glow plugs, but I've waited for those to do their thing and it still does it. Also, it does it hot or cold, glow plugs are only needed when the motor is cold. I'm guessing it's shut off solenoid related.
One thing, I went on trip for a week recently and pulled the ignition relay and the fuel pump relay as an anti theft. Worked fine before I left. Come back home, replace relays and now this nonsense. Likely just coincidental but thought I'd mention it

They dont use glow plugs. What Rumblefish 72 said makes sense. I have even had the linkage off the fuel solenoid get rusty and stick where ssometimes the truck wont run and then sometimes it wont shut off. It has the two windings in the fuel cut solenoid as it kinda like a starter that has the pull-in and hold-in windings. But I have seen the ball sockets on the linkage that moves coming off the fuel cut solenoid get very rusty and stick. Ron

Yep, no glow plugs, they use a heater on the air intake. I have been in close to zero degree weather, never needed to wait on either of my Cummins, a 96 and 2000 24V. A cornbinder in a Ford, it will not start with out the glow plugs even at 70 degrees it seems.

Does it have a GSK in the pump? I have a 4000 rpm GSK on my 97 and I have to apply just a little pressure on the throttle to get it to start.
If the run solenoid is not working it will not start at If the lift pump is failing which is rare on a 12 valve it would start but run very poorly under load.

Nope, spark plugs.

Sorry, I knew they didn't have glow plugs and use a grid heater, I just use it as a common term (used to all the old tractors on the farm that had glow plugs). Truck is completely stock, and once it starts it runs perfectly. I talked to my uncle (who I bought it from) and he put a lift pump in it at some point so unlikely it's that. I'll pull the solenoid off and take a look

It'll run without the shut off solenoid. Just won't shutoff unless you manually pull the fuel lever down or stall it by covering the air intake at the turbo. Mine wore and got stuck. It would start but then had no power. Remove it and see what happens, couple of bolts. I know also that there is a check valve in the return side of the pump that can hang up and cause problems. It is replaceable on the vehicle.
Doug

You can disconnect the solenoid and wire the fuel shutoff lever in the run position, hit the key and see if it still acts the same.

This is my plan, I took a look at the solenoid and just noticed that it's held on with a pair of vice grips lol. Probably a good indication of my woes

too low of idle will do that. 750 in gear with a/c on.

It idles around 800+ rpm now

i think it's the coil wire or the muffler bearings. those clog frequently........

Got the fuel shut off solenoid mounted properly today and it solved the problem, starts right up

Sorry, I know crap diddly about diesels, my oldest daughter is the diesel expert in the family, she used to be a mechanic in the Army.

Hillbilly fix:
When I took my solenoid off I tested it and it worked fine but the boot was non existent. I could order a boot but it had to come from the US ($30-$40), which is no biggie but it takes awhile. I called Cummins and they want to sell you a whole solenoid assembly for $700! From the pics I saw of an oem boot it reminded me of those punchy balloons you could get as a kid. So I went to the party store, bought a pack and brought them home. They looked about the right size so I picked the least flamboyant color, cut the end off the body and slipped it on. Fits pretty decently lol! AND cost me about 50 cents! It's made of fairly heavy rubber so it should last abit hopefully