Bus won't start. help

[usplusearth]

Hey guys. Im new to bus life and to this website so please bare with me. I have a 2001 Thomas Fright-liner, 5.9L Cummins engine with hydraulic brakes. The bus was running perfectly the other day and hasn't really given me any issues till this week. i went to start the bus and it wouldn't start. it turns over and makes a wir wir wir sound but wont start.

1. its in neutral, i tried switching gears several times and putting it back in n. didn't work.
2. emergency backdoor, roof, side windows and front door are all closed and locked.
3. I thought it might have something to do with the fuel injections so i replaced the pump on it and that didn't help.
4. i had a mechanic look at it today and he said the engine looks good and thinks it might be some kind of safety feature or electrical maybe?
5. when i have the key in, shows two symbols in red, but im not sure if those always pop up when you first put the key in or not.

Any thoughts or suggestions!? thanks

[family wagon]

It's a bit fuzzy, but the indicator on the left looks like a low oil pressure alarm and the one on the right is a parking brake applied warning. Both are normal to see when the engine isn't running.

My (very limited) experience with emergency exit interlocks has been that if the interlock is interrupted the starter motor won't spin. I wouldn't expect an interlock to kill a running engine, nor to interrupt fuel while cranking to start an engine. Since your starter/engine is spinning my guess is you don't have a safety/interlock problem.

Most likely then is fuel. Maybe you had a fuel challenge before, and you surely do after replacing the pump! I'm only familiar with the 24 valve ISB version of the 5.9 engine, so if yours is the 12 valve flavor, the following won't be of much help. Before you begin, put a charger on the battery and wait for it to get to a fully charged state.

Turn the key all the way to the start position, but only for a moment and then let it spring back into run. Listen for the lift pump to run. It should run about 30 seconds after bumping the starter. When it stops, turn the key off and repeat the process two more times. This ensures that the lift pump purges the air from the fuel lines and filter.

Next, crank the starter for 10-15 seconds and then let it rest (ie cool down) for 30-60 seconds. Do this 3-4 times if necessary. Usually on this engine it isn't necessary to loosen injector lines to bleed air out of them, it manages to push the air out on its own and the engine begins to sputter and stumble and then runs. Still, you could loosen one just to verify that the injection pump is pushing fuel if you wanted to. If after all these steps it's still not running, then I'd definitely loosen one injector connection to verify fuel.