Engines won't stay running

[PJHoffnet]

Cummins 330 diesels ... will crank and run as long as they key is held in the start position, but engines stop as soon as key is released. Thoughts?

Thanks in advance.

[AaHubb]

You said engines, so problem is common to both? That would seem to be an electrical issue unless you have a single fuel source feeding both engines.
..Aaron

[PJHoffnet]

Both engines, same issue. Batteries were off charger for about five days post IRMA ... but have been back on charge since then. The fact they crank seems to lead me to thinking the batteries are ok (separate battery for each engine/starting).

[bud37]

I really know zero about your diesels,...but like some older cars there was always something that was bypassed when the key was in start position....perhaps you could see what are the bypassed items and focus there....seems that in run something is shutting down, but what, fuel related ???....not much help heh.but...again hope you find it.

[mjk1040]

You say batteries were off for 5 days. Did they discharge below say 10 volts? If so may have to reset computer that controls engine functions. May try just disconnecting all engine supply batteries for a minute and reconnecting to reset the computers. It's seems that when in the run position, 12volt power is not being supplied to the fuel injection pump solenoid thus shutting off the fuel supply to the engines just like you turned the keys off. Low voltage to the engine computers will screw them up. You may have to have the engine tech reset the computers with diagnostic machine. Good Luck, hope you find the issue soon and let us know what you found!

[Viper]

Test your batteries properly or do a voltage drop test while starting the engines. Don't know if your vintage is computer controlled but if they are, the ECM won't like a voltage drop.

When you say they "run" are you sure they're actually firing or are they simply being spun by the starter until you release the key? Can you throttle up with the key in the start position?

[PJHoffnet]

Thanks for all the inputs ... trouble shooting begins as soon as I can carve sometime for the boat. Will let you know what I find.

[Lyndon670]

The other issue could be your keyset. The keys to my 506 (Volvo) are smart chipped. I cant switch the keys from side to side or replace them with generic keys. I don't know about the Cummins, but perhaps if its similar you have lost a match?

[PJHoffnet]

Source of the post .

When you say they "run" are you sure they're actually firing or are they simply being spun by the starter until you release the key? Can you throttle up with the key in the start position?

Probably just being spun by the starter now that I think about it. I did try the throttle and had no change in sound while cranking.

[PJHoffnet]

Source of the post The other issue could be your keyset. The keys to my 506 (Volvo) are smart chipped. I cant switch the keys from side to side or replace them with generic keys. I don't know about the Cummins, but perhaps if its similar you have lost a match?

They are just simple, old, keys-no chips, but that was a good thought.