Cummins won't start

[Waterford]

I have a Cummins 5.9 in my Nordic Tug 32. My wife cranked it without turning the key and now it will not start at all. Seems fuel starved but cranks fine. Is there something on the injector pump that I need to reset? Filters are fine. Any suggestions are appreciated.

 

[No Mast]

As with anytime when you're cranking for long periods, start by shutting down the raw water intake. Then check your manual, there should be specific locations in the fuel line to open to bleed. Usually one of the injector lines will do, crack it open and crank till fuel come out. If the engine starts, open the raw water first, then tighten the fuel line.

That's what I would do, but i'm not a mechanic, proceed at your own risk or call a mechanic

 

[capt jerry]

As with anytime when you're cranking for long periods, start by shutting down the raw water intake. Then check your manual, there should be specific locations in the fuel line to open to bleed. Usually one of the injector lines will do, crack it open and crank till fuel come out. If the engine starts, open the raw water first, then tighten the fuel line.

That's what I would do, but i'm not a mechanic, proceed at your own risk or call a mechanic

if you have a lift muffler it might be full from cranking,that will stop it from starting because of back pressure, had that problem way back when,had to drain the muffler?

 

[Carolena]

Not sure of you year, but our 2001 NT 32 won't crank without the key on. Anyway, it may be just coincidence that it started acting up after cranking with the key off, but we have friends with the cummins 6bt (I'm assuming that is what is in your boat) and they have replaced two fuel stop solenoids in the past 10 years (its a twin and each motor has required one replacement). Unless you have a newer electronic motor, you should be able to manually hold the fuel open while someone cranks to see if it will start. I also suggest putting your question out to the NT owners forum (you should join if you have not already) and also perhaps check out BoatDiesel.com. I have a membership and find it is worth the $25 per year.

 

[Baker]

Not sure of you year, but our 2001 NT 32 won't crank without the key on. Anyway, it may be just coincidence that it started acting up after cranking with the key off, but we have friends with the cummins 6bt (I'm assuming that is what is in your boat) and they have replaced two fuel stop solenoids in the past 10 years (its a twin and each motor has required one replacement). Unless you have a newer electronic motor, you should be able to manually hold the fuel open while someone cranks to see if it will start. I also suggest putting your question out to the NT owners forum (you should join if you have not already) and also perhaps check out BoatDiesel.com. I have a membership and find it is worth the $25 per year.

I guess they could malfunction and cause the engine not to start. But generally, the solenoids are powered closed and fail open. IOW, the failure of a solenoid would prevent your engine from shutting down...not from starting.

I do have 6BTAs in my boat. Randomly my port engine is stubborn to start. It is not a compression issue. I mentioned this to the a cummins folks and there is something on the injection pump that needs to open to provide fuel. I do not remember if he said it was oil pressure powered....fuel pressure powered...or a mechanical linkage. I have recently got into the habit of exercising that throttle before starting and it has not hiccupped since. I honestly have no clue if that is doing anything or why but the results are good...

 

[DavidM]

Cummns uses a power to start fuel solenoid, not the more typical power to stop as on Yanmars. If the solenoid is not getting power it won't start. So first turn the key on and check for power at the solenoid. If not then you probably have an electrical problem. If you do have power, make sure it is traveling all of the way. You can hold it down mechanically and try to start or bleed the engine. If it starts then it is likely a bad solenoid.


And yes, turn off the raw water and dump the lift muffler before doing any more cranking.


David

 

[Carolena]

Our friends have older versions that we have in our boat and I know it has a different fuel setup (it is also a much higher HP version), but I know that whatever broke it would not allow it to start unless one of them went into the ER and held the thing open. Once they had it started it would continue to run, but I seem to recall that they had to put a wire or zip tie on it. It happened once when we were on a group cruise.

 

[Waterford]

I understand the bleeding process, but not the "why". How would air get into the lines in this situation? Filters were changed AFTER it would not start. I had not considered the exhaust and hope I don't have to go that far! Thanks for your help.

 

[Waterford]

OK, based on all your inputs, I'm going after the solenoid. Thanks.

 

[Baker]

Cummns uses a power to start fuel solenoid, not the more typical power to stop as on Yanmars. If the solenoid is not getting power it won't start. So first turn the key on and check for power at the solenoid. If not then you probably have an electrical problem. If you do have power, make sure it is traveling all of the way. You can hold it down mechanically and try to start or bleed the engine. If it starts then it is likely a bad solenoid.


And yes, turn off the raw water and dump the lift muffler before doing any more cranking.


David

Well dammit...I guess I learned something about the engines in my bilge. So you are saying electrical power is required to keep the solenoid open and therefore the engine will fail if power is lost to that solenoid? Sorry if this is a hijack....

 

[bayview]

Yes Baker, power required to run.

 

[bayview]

Waterford you don't say what model 5.9 The QSBs have an electric fuel pump.

 

[Ski in NC]

To help in troubleshooting: The Cummins 6bta solenoid is energized with the key, but the pull in circuit is powered by the starter. So it will not move with just turning on the key, got to bump the starter, then it will snap in.

To the OP, if you changed fuel filters as part of troubleshooting this, you will likely need to work the primer button on the fuel pump to purge enough air to start.

 

[Waterford]

It is a year 1999 6BT5.9. I spoke with my mechanic today, but he has not been to the boat yet. He is also suspicious of the solenoid. I'll check power to that tomorrow. Thanks for all the input!

 

[Maerin]

Backup plan

If the solenoid is on a CAV pump, check as a previous post advised for power to the solenoid. If the solenoid fails, it will shut the engine down, and it won't re-start. I've had one drop out a number of times but start right back up. Very unnerving.

If one fails and you're away from parts, all is not lost- the solenoid can be removed from the pump, and the plunger and spring removed from the solenoid, then the solenoid replaced. The engine will run. It won't shut off in response to the key or stop button, but it will run! To shut off the engine, simply close the spring loaded fuel shutoff valve on the top of the injector pump. No harm in running that way until parts arrive.

 

[Ski in NC]

The above post covers the 6bt 210/220 with CAV pump. Other posts deal with the external solenoid on the 6bta 260-370 with ND or Bosch pumps. Two completely different pump and solenoid layouts.