My Cummins just stopped!

We were pulling into the Ft Myer Beach mooring field and my QSR 5.9 Cummins diesel just stopped. I quickly dropped the anchor and did some quick troubleshooting before calling TowBoatUS for a tow to a mooring. Engine would turn over, but no 'fire'.
After further inspection, I've found a blown 2 prong 25amp automotive type fuse, replaced it and it blew again, immediately. Looked on the port side of the engine near the ECM stuff, and found a 'plug in' that appeared to be burned, so unplugged it, took it apart, cleaned the connections and tried fuse again, it blew.
Now waiting until at least Thursday before a Cummins mechanic can get out here.
Anyone have any ideas?
I really understood my little Yanmar diesel on my sailboat, but this is a totally different animal, Lots more electronic stuff...

On mooring #57 at Ft Myers Beach mooring field
There could be worst places to be stuck.

Wm Mayberry
OPTIMYSTIQUE
Mariner 40

I recommend you subscribe to boatdiesel.com. Many knowledgeable Cummins professionals and experienced boaters on there. The answer may already be on there, otherwise you can get some informed opinions on your issue.

Boatdiesel is your best bet, but here is one thing you can check. I know that this "trick" will work on the mechanical 6B, but not sure about the all electronic QSB.


There is a run solenoid mounted near the injection pump that moves a lever on the pump that lets it run. If that solenoid isn't pulling in, then the engine won't start and if was running when it failed or lost power to it, the engine will stop.


You can manually pull up (or is it down?) the lever that the solenoid moves and see if it will start. If it starts, then you need to troubleshoot the power circuitry to that solenoid or the solenoid itself. But with a burned connector, it could be both.


My understanding of the electronic QSB is if a sensor detects something out of whack, the computer will limit revs and power but not shut down the engine- if the computer is ok. The run solenoid is one of the few things (other than the computer itself) that will keep the engine from running if it is bad or if it isn't getting power to it.


David

The QSR 8.3 is a conversion to a common rail set up as I understand, and yours may be the same. Blown fuses/ burned plug indicates to me a shorted circuit. I high $$ tech with a laptop is probably the best route. You would think it stored a fault code making locating the problem go quickly. Good luck!!


1983 Present 42 Sundeck
Twin Lehman 135's

Probably is a QSB 5.9. Full electronic common rail engine. Could be electric lift pump shorted out and that's blowing the fuse.

Yep, My bad, it is a QSB 5.9
Hopen to get some idea next Thursday when Cummins guy comes.
Good thing about diesel engines, they run and run as long as they have fuel and air, now I've got this electronic issues. Now I'm dead in the water.
Hopefully I can find a solution if this happens again away from civilization

Dang those new fangled diesels with electronics. Long live the ancient FL 120/135. Wmiii,I hope the issue can be speedily resolved.

Yea, that's the downside of electronic engines. EPA has mandated low emissions which requires electronic engines. But electronics fail. How much emissions are created recovering from such a failure? Towboat, shipping parts, mechanics traveling? And what is the emissions benefit from making trawler engines cleaner? Is it worth it??

Old skool engines just needed air, fuel, oil and cooling to stay running. Sad that elegance is disappearing.

Yup, very thankful for my mechanical 6B's. A Cummins mechanic will be your most expensive route.

Like others have said, check boatdiesel.com and get a heads up of what to do, then you can either try and fix it yourself or hire some one to fix it, but if you've done all the trouble shooting and you hire someone it will be quicken and cheaper. Buy the part before hand.

Good luck.

A blown fuse, 25 amps, multiple times is clearly a dead short. Since you have nothing to do until the Cummins guy comes, you may as well carefully inspect the wiring harness on this engine, look for possible chafe points to the block. If you find nothing untoward there have a careful look at the back of engine instrument panel(s) at he helm station(s). In my experience, blown fuses of this sort are rarely an engine induced issue, they are usually something related to the engine installation, wiring harness run or accessories connected to the engine instrument panel.

That fuse likely supplies power to the entire wiring harness, from the engine all the way to the key switch and instrument panel. A short anywhere along the way, or at the panel, could be the culprit. If the fuse is blowing as soon as you turn the key on, then it's something between the load side of the key switch and the engine, or on the engine itself, but not the starting/cranking circuit. If any work has been done along or near that wiring harness run, engine to instrument panel, or around the panel itself, I'd check there first.

While it would be nice, if the engine can't be powered up, i.e. power on with key switch on, before the fuse blows, a computer will do little good as the engine's ECU won't power up, the mechanic will have to use his experience and electrical troubleshooting skills. If it's something he's seen before, on the engine, he may go right to it, however, if it's in the boat's harness, that's a bit more challenging, so if you can identify it you'll save yourself some money, even if you can't fix it yourself.

Love your avatar Steve.

Thanks, Steve.
That should keep me occupied for a few dsys.
Appreciate the guidance

Wm Mayberry
OPTIMYSTIQUE
Mariner 40
Ft Myers Beach mooring field

Wm, be sure to let us know what you find.

Don't forget to check for a short in the key switch.

Hopefully, I have attached a picture of the port side of my engine and you can see the redish 'plug'. That is what appears to have burned or shorted out.

I can't tell anything by that picture. You need to get a hold of a service manual with a wiring diagram. As mentioned, go join boatdiesel.com

Wmiii said:

We were pulling into the Ft Myer Beach mooring field and my QSR 5.9 Cummins diesel just stopped. I quickly dropped the anchor and did some quick troubleshooting before calling TowBoatUS for a tow to a mooring. Engine would turn over, but no 'fire'.
After further inspection, I've found a blown 2 prong 25amp automotive type fuse, replaced it and it blew again, immediately. Looked on the port side of the engine near the ECM stuff, and found a 'plug in' that appeared to be burned, so unplugged it, took it apart, cleaned the connections and tried fuse again, it blew.
Now waiting until at least Thursday before a Cummins mechanic can get out here.
Anyone have any ideas?
I really understood my little Yanmar diesel on my sailboat, but this is a totally different animal, Lots more electronic stuff...

On mooring #57 at Ft Myers Beach mooring field
There could be worst places to be stuck.

Wm Mayberry
OPTIMYSTIQUE
Mariner 40

Click to expand...

What happens if you unplug that plug and replace the fuse? That should narrow down to engine side or boat harness side.
Sorry I missed reading this Friday morning, we were on ball #41.

We did that and still blew. I'm thinking the problem is on the part it plugs into.

We saw you here a couple of days ago.

Wm

Capt.Bill11 said:

I can't tell anything by that picture. You need to get a hold of a service manual with a wiring diagram. As mentioned, go join boatdiesel.com

Click to expand...

It appears to be the power supply to the ECM, I think. Found thst on line wiring diagram.

Is the fuse up stream or down stream of the plug?

I doubt I can help with specific advice on the electronic Cummins, but there's a trick I use in my shop to find shorts:

Get your multimeter and set it on "beep". Connect the black lead to ground with an alligator clip. Clip the red lead to the "load" side of the fuse. The meter will then "beep" continuously due to the short circuit.

Now go through the wiring and wiring harness, wiggling and moving all the components and wiring bundles. The instant the "beep" stops, you've found the place that the short is located.

Like the others, my hunch is you have a chafed wire someplace, probably in the instrument panel (do you have a panel on the flying bridge?) or the harness to the engine. The chances of a short in the harness that is integral to the engine is pretty low.

GOOD LUCK!

J.S.

Try Tony at tony@sbmar.com check out his web site Custom Cummins Marine Diesel Repower Specialists he knows all weaknesses of Cummins.

Bill:

How did you make out finding that short circuit?

Hopefully you've found it and now you're cruising in some exotic place that doesn't have internet service.

...it's always good to hope.

JS

Mechanic just left. Looks like a lot if corrosion on wiring harness connectors. He's taken ECM to shop to see what shape it is in.
No signs of water leaks, but even found some moisture in connector.
Now wait and see what's next.
It is what it is!

Wm

Could be from detailers washing engines. I've made a lot of money recovering from recently cleaned engines.

Expensive news!
Needs ECM and wireing harness.
Don't know where corrosion came from or when.
Should be good to go tomorrow (good news)

Wmiii said:

Expensive news!
Needs ECM and wireing harness.
Don't know where corrosion came from or when.
Should be good to go tomorrow (good news)

Click to expand...

So out of curiosity, how much does an ECM cost? I think this is a relevant general question because my reply to people that question the reliability of common rail engines is that you could carry a spare ECM. Is it so expensive as to be too costly to carry a spare?