Onan MDK genny fault code 36?

[Nick_H]

Genny stopped underway, but restarted and seems to be running fine now. Last fault code registered is 3, and second tier code is 36. Anyone know what this fault code is? Genny is 2004 vintage.

 

[jimmy_the_builder]

On my MDKBH generator, fault code 36 is 'unknown shutdown', triggered by a transient loss of rpm. Looking at the manual it says

Corrective Action:
1. Reduce the number of loads on the genset.
2. Check fuel level and refill as necessary. (Note: The genset fuel pickups are probably higher than thepropulsion engine fuel pickups.)
3. Prime the engine fuel system for at least 30 seconds (p. 3-3).
4. Check all fuel fittings for fuel and air leaks, tighten as necessary and reprime.
5. Replace the fuel filters and reprime (p. 4-5).

 

[admillington]

Nick

https://www.dropbox.com/s/4ccthqyoveu0v7c/Onan%20Operator%20Manual.pdf?dl=0

The link contains the manual for my Onan 17.5KW unit - 36 seems to be a fault relating to a more than 0.5 second drop below 1000 rpm.

I have Onan's Senior Engineer coming to my boat next Tuesday - if the fault continues or you need more info I will ask him and et back to you.

-Andrew



-Andrew

Genny stopped underway, but restarted and seems to be running fine now. Last fault code registered is 3, and second tier code is 36. Anyone know what this fault code is? Genny is 2004 vintage.

 

[Nick_H]

Oops, I've just found they are listed in the back of my manual! :ambivalence:

It's "engine stopped without command by controller" with corrective actions broadly as per JTB's list above.

Seems I need to check the fuel system from start to finish

Thanks for the replies

 

[jfm]

Or ask J to turn off all the hairdryers and stuff, and that gyro!

Before spending time on fuel, consider this: on my boat, if the boat is stopped so that e/room ventilation kinda stops and the genset is sucking in warm engine room caused by recently shut down engines, a demand overload from too many loads causes the genset's engine to stutter/stall before the current overload breakers trip. If you look at the Kubota data sheets you see that the engine only makes something like 70% of its nominal BHP if breathing 70degrees C air. That's why I specked directed ducted air intake on my current boat, so the gensets breathe external air not e/room air, with fan assist. If this was your problem it's nothing to worry about

Also a lack of fuel supply has its own fault code doesn't it? I can't remember. Too hot intake air doesn't have a fault code (other than 36, as it were)

 

[Nick_H]

Or ask J to turn off all the hairdryers and stuff, and that gyro!

Before spending time on fuel, consider this: on my boat, if the boat is stopped so that e/room ventilation kinda stops and the genset is sucking in warm engine room caused by recently shut down engines, a demand overload from too many loads causes the genset's engine to stutter/stall before the current overload breakers trip. If you look at the Kubota data sheets you see that the engine only makes something like 70% of its nominal BHP if breathing 70degrees C air. That's why I specked directed ducted air intake on my current boat, so the gensets breathe external air not e/room air, with fan assist. If this was your problem it's nothing to worry about

Also a lack of fuel supply has its own fault code doesn't it? I can't remember. Too hot intake air doesn't have a fault code (other than 36, as it were)

Hmm, you may be onto something, though in my case I'm fairly sure it's not related to load as we had very little running.

Following the recent thread on here about engine fans, I disconnected my noisy extract fans on the basis that the engines shift loads of air anyway when they're running, and the fans stop shortly after the engines are stopped so do little for cooling after a trip, and the batteries are separately vented. Fans were definitely set to extract, not feed fresh air.

On the trip in question, as it was the first trip after anti fouling, once the engines were warm I did a short blast at WOT to check max speed with a clean hull and stern gear. Engines of course got hotter with more work being done (separate thread on that), and after a few mins I eased back to 800 rpm, 8 knots. Maybe the genny was then sucking in very warm air and despite having a low load, only the gyro running, that may have caused the shutdown.

That would explain why it has run fine since.

 

[ARE]

As you know fault code 36 is engine has stopped with command from controller, so either you have a fuel supply problem, combustion air supply problem or as JFM suggested the ambient air temperature has de-rated the engine output below the load on the generator and the engine has stalled.

If it restarted straight away with no cranking? I would suggest fuel is not your issue.

Regards Anthony

 

[Nick_H]

Thanks Anthony

It did need some cranking to restart, but has then run fine since. I've checked all the fuel system and can't see any leaks, and drained both fuel filters and changed the pre-filter for good measure. It had some black staining, but certainly looked serviceable so I doubt that was the issue. I've run it for quite a while in port now under different loads and still no further issue.

I need to get out and try it underway again to see if the problem re-occurs.

 

[Nick_H]

I'm rekindling this thread as I haven't managed to sort the problem yet, so was hoping someone may be able to help.

In summary, the genny starts OK, and will run fine under high or low load whilst at anchor or in port, but underway it keeps stopping. The fault code registers as "engine stopped without command from controller". It happens even at displacement speed in calm sea. The only change I've made recently is a new battery, and I've checked that the terminals are secure and that the alternator is charging OK while genny is running.

I've checked the whole fuel system and can't see any leaks, and I've changed the fuel filters.

Any ideas?

 

[admillington]

Nick

Have PM you the details of the senior engineer at Cummins Onan - he fixed my issue when no one could.

Andrew

 

[jrudge]

Looking at the fault code at the beginning of the thread

1. Reduce the number of loads on the genset.
2. Check fuel level and refill as necessary. (Note: The genset fuel pickups are probably higher than thepropulsion engine fuel pickups.)
3. Prime the engine fuel system for at least 30 seconds (p. 3-3).
4. Check all fuel fittings for fuel and air leaks, tighten as necessary and reprime.
5. Replace the fuel filters and reprime (p. 4-5).
Read more at http://www.ybw.com/forums/showthread.php?427918-Onan-MDK-genny-fault-code-36#U16FpyW8a4Cfjugo.99


The main message is "fuel".

So the boat will be (a) moving (b) the engine bay will be hot

I just wonder if either a or b is causing a fuel line crack to open slightly letting in air, hence causing the revs to dip and the code to appear?

The snag is even if I am right how on earth you go about finding the fault.

I assume the tanks are full? As per 2 above there could be fuel slosh, also letting in air. Above you say it needed some cranking to get going, and I believe they are all self priming so this would suggest to me air in the fuel.

I have had air in an engine fuel line once, and it showed no symptoms on a full tank, but as the tank fell lower and it would draw air. No idea if this is typical or not.

 

[ARE]

I'm rekindling this thread as I haven't managed to sort the problem yet, so was hoping someone may be able to help.

In summary, the genny starts OK, and will run fine under high or low load whilst at anchor or in port, but underway it keeps stopping. The fault code registers as "engine stopped without command from controller". It happens even at displacement speed in calm sea. The only change I've made recently is a new battery, and I've checked that the terminals are secure and that the alternator is charging OK while genny is running.

I've checked the whole fuel system and can't see any leaks, and I've changed the fuel filters.

Any ideas?

Hi Nick,

There could be a number of causes for this, basically the engine has stopped without the Control PCB asking it to.

So number one would be lack of fuel and the easiest way to test this is to run the generator from a separate fuel supply. We normally you a 25lt can secured in the engine room. if the generator runs fine it could be that you have a fuel hose collapsing on the inside when it gets warm or a air leak somewhere.

If the generator stop's on the auxiliary tank then you could have a faulty/intermittent electric fuel pump, these are mounted on the front of the engine next to the fuel filter. they are a shuttle pump and rattle with no fuel in them and quieten down when pumping fuel, so if you listen when the generator has stopped and you try to restart it you can tell if fuel is present.

Regards Anthony

 

[jfm]

Hi Nick,

There could be a number of causes for this, basically the engine has stopped without the Control PCB asking it to.

So number one would be lack of fuel and the easiest way to test this is to run the generator from a separate fuel supply. We normally you a 25lt can secured in the engine room. if the generator runs fine it could be that you have a fuel hose collapsing on the inside when it gets warm or a air leak somewhere.

If the generator stop's on the auxiliary tank then you could have a faulty/intermittent electric fuel pump, these are mounted on the front of the engine next to the fuel filter. they are a shuttle pump and rattle with no fuel in them and quieten down when pumping fuel, so if you listen when the generator has stopped and you try to restart it you can tell if fuel is present.

Regards Anthony

I think Anthony you can listen to the fuel pump if, after the genset has shut itself down, you turn everything in the engine room off and then hold the "prime" rocker switch on the genset. You'll hear whether the pump is smoothly pumping fuel, or rattling due to air

 

[ARE]

I think Anthony you can listen to the fuel pump if, after the genset has shut itself down, you turn everything in the engine room off and then hold the "prime" rocker switch on the genset. You'll hear whether the pump is smoothly pumping fuel, or rattling due to air

Absolutely correct.

Regards Anthony

 

[Nick_H]

Thanks gents, I'll try that in a couple of weeks when I'm next at the boat.

 

[Nick_H]

Genny engineer came today. The problem had increased so that genny would start and always cut out after 10 secs. The fault code also changed to 58, which is an exhaust temp alarm, but raw water was flowing ok, and anyway it couldn't overheat in 10 secs. Problem traced to a faulty temp sensor. I'm concerned that this would always have given a fault code 58, so doesn't explain the initial problem that gave code 36, but engineer is convinced that it could have, and that the new sensor will fix it.

Thanks again for all the input on this thread

 

[Hurricane]

Genny engineer came today. The problem had increased so that genny would start and always cut out after 10 secs. The fault code also changed to 58, which is an exhaust temp alarm, but raw water was flowing ok, and anyway it couldn't overheat in 10 secs. Problem traced to a faulty temp sensor. I'm concerned that this would always have given a fault code 58, so doesn't explain the initial problem that gave code 36, but engineer is convinced that it could have, and that the new sensor will fix it.

Thanks again for all the input on this thread

Thanks for posting the result, Nick - faults like this are always worth remembering.