Class A 330 diesel won't shut off

usersmanual wrote:
Now Iam more interested to find out how a 7 pole trailer plug got wired to a diesel shut off solenoid and how that caused $15000 in damage.

Me too.

Over the years there have been several time where my engine will be slow to stop running after turning the key off... several seconds delay. Today it decided to not shut off at all while I was refueling and then when I got home after a eight week trip...I guess that's better than not running. Had to disconnected the neg battery terminals and the engine disconnect switch to get it to stop after pulling the fuse for the signal from the key in the back run box did not stop it.

Isolated the problem to a bad diode on the Bird board which was back feeding alternator voltage even though the key was turned off. When the alternator voltage gets to 13.3 the Bird activates the big boy to start charging the house batteries too. With solder joints this big on the bird board it's fairly easy to replace the diodes yourself which is what I plan on doing. Hopefully we will hear back from him.

Today I got around to putting in the $3 MR750 diode in the Bird board that was back feeding power so my engine would not shut off...this fixed the problem. I think the OP has the same problem and have talked to him about it.

Brett:

It was an F350, I think, maybe about 10 years old. It's a few years back and memory fades at my age!

I had a '78 VW Rabbit diesel that also developed the habit of burning the lube oil. It had well over 200,000 miles on it. If I got much over 60 mph it would start accelerating on its own. I would have to apply the brakes to bring it down below 40 mph and then it would stop burning lube oil and I could drive normally again.

The only way the work truck in the above post could have been stopped would have been to put it in gear (high gear if a stick) and with brake on hard let out on the clutch and hope that would do it. If an automatic, stand back so the pieces don't hit you. With my Duramax I can put an emergency air shut off on the engine if I so desire.

Detroit Diesel? when he said parked his work truck in the driveway I thought he meant like a 3/4 or one ton pick up type thing lol

Frank,

Was this on a Detroit Diesel Two stroke or a more modern diesel?

Always be very leery of diesels that won't shut down. A neighbor had that issue with his work truck (owned by his employer). He got home, pulled into the driveway and switched off. It kept running, and got going faster and faster. He even disconnected the fuel pump, but to no avail. Eventually, there was a big bang and the crankshaft appeared outside the engine, in bits.

The diagnosis was that the engine had started using its lube oil for fuel and only stopped when it had burned enough of it to starve the bearings and break the crank.

Now Iam more interested to find out how a 7 pole trailer plug got wired to a diesel shut off solenoid and how that caused $15000 in damage.

The OP has a 04 Diplomat, very close to my 04 Dynasty electrically. Mine would not shut off because of a bad diode on the Bird board back feeding 12V to the solenoid in the injection pump. The Bird uses 13.3 Volts from the alternator to know when to start charging the house batteries. Interestingly my ABS light has come on and the OP has the same problem too. Hopefully the ABS issue goes away when I replace the diode on the Bird. I have a MR750 diode on order...$3.

gatorcq wrote:
call cummins support.
All Class A Diesels engine are computer controlled PERIOD.
That being said, when you turn the key to off the computer then turns off a valve which is spring loaded. Thereby chocking the fuel off

Maybe you can enlighten me here.
I have a Ford type or standard solenoid back by the HEUI fuel pump, but also could be for the air compressor. Just trying to figure out, with what you're saying here and if this solenoid is what actually shuts off the fuel. If so and to work like you're saying, it would have to be a continuous duty type for holding the valve open when the engine is running. You can easily see it in some of these photos.
Cat engine pics
A better closeup of it here... Solenoid