1994 suburban will not keep charge from battery,

Once jumped n the jumper cables are removed it dies again. I would think it's not charging , alternator problem maybe .Is the battery light lit on the instrument cluster ?

I would suggest that you have a load test done on the existing battery as the indications are that it has several dead cells
the vehicle starts of the jumper battery but on removing the leads there is nothing with which to keep the ignition circuit operational
alternators need a current from the battery to start charging as they do not have residual magnetism in the stator so when you take the jumper leads off there is nothing to keep the alternator charging hence no power for the ignition circuit.

Either a shorting wire off a wiring loom somewhere in the electrics or a boot light or internal light not switching off.did you recently fit a new item to the vehicle as this could be part of the problem.

Both, the alternator is not charging the battery.

the battery light comes on to tell you there is a problem with the charging system.

Check the voltage at the battery with the vehicle running. You should see more than 14 volts. If its less than the alternator is likely not charging.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Is the suburban running? Sometimes a batery is so dead that it simply cannot be jumped off with another vehicle, even if you let it sit and "build a charge" It might be time to simply replace the battery. Napa will use a Midtronics teator and test the battery for you to let you know exactly how good or bat the battery is. Of course I assume that you are connected properly with the cables and the cables are not broken in any place or corroded.

If you havent replaced the battery I would start there. If the battery has a dead cell in it then it will effectively remove the charge that your alternator is putting out causing your vehicle to stop running because it has no power. I would jump start the car without the battery hook up and remove the cables and see if it runs that way. If it does you have a bad battery.

It sounds like an Alternator problem.
Remember the Battery only Starts the vehicle and runs nominal operations. The Alternator actually provides the electricity to run the Engine operations. With that being said: Start the vehicle, jump start it if you have to. Remove the Negative Cable from the Battery or remove the jumper cables. If the Engine dies after doing this, the Alternaotr is bad and needs to be replaced. When the Alternator begins to die, it starts draining the Battery. During normal operation it is the Alternator that sends a small trickle charge back to the Battery keeping it charged-up.
Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

test the battery make sure its good, also when it wont start does the engine spinor do you get nothing ?

if u cant find any info about the diode try a used alternator should b cheap fix